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FDS Assignments Course: VBRF16 – Simulation of Fires in Enclosures, Lund University

Supervisor: Linn Svegrup & Jonathan Wahlqvist Author: Anders Lynnér

April 8, 2014

[I]

Abstract This report is made in the intention of describing and presenting results of different individual assignments

carried out within the course VBRF16 – Simulation of Fires in Enclosures given at Lund University. The

assignments were to simulate with Fire Dynamics Simulator (FDS); a free burning plume, radiation between two

parallel plates and fire within a small compartment. In total there were 22 different simulations carried out, and

thereby a lot of results generated.

A great part of this report is dedicated to investigate results of the simulations, asking the frequent question:

“Why does it look like this?”. The conclusions are of a general manner, trying to answer this question and

establish things to think about when using FDS.

The conclusions derived from this report are:

The mesh of the burner and the burner specifics must be well defined in order to represent:

a. good enough deal of the turbulence structures

b. temperatures that have any correlation with reality

To do this, one has to do several simulations until grid independence is reached.

It is difficult to decide if the radiation model is sufficient, since a coarse grid may generate better results

with fewer solid angles than a fine grid with the same amount of angles. To know if it is sufficient, one has

to make sure that they have:

a. achieved grid independence

b. no scattering in their radiation patterns.

The grid sizes have an impact on the temperatures in the compartment, and thus an impact on the velocities

by the opening. A coarser grid gives a higher temperature, and wider bounds of the velocity profiles.

The radiative fraction is important to specify correctly when trying to achieve reality converging results.

It is important to compensate HRR if turning off radiation model, there will be large differences in the

results and reality otherwise.

Emissivity of the walls has in the LES application little or no effect on the temperature or velocity profiles.

[II]

Contents

1 Introduction ................................................................................................................................................... 1 1.1 Method ................................................................................................................................................... 1 1.2 Description of assignments .................................................................................................................... 1

2 SUB1 ............................................................................................................................................................... 3 2.1 Computational domain .......................................................................................................................... 3 2.2 Fire ......................................................................................................................................................... 3 2.3 Time step ............................................................................................................................................... 3 2.4 Devices .................................................................................................................................................. 4 2.5 Hand calculations .................................................................................................................................. 4 2.6 Results ................................................................................................................................................... 5 2.7 Observations and discussion .................................................................................................................. 6

3 SUB2 ............................................................................................................................................................... 8 3.1 Computational domain .......................................................................................................................... 8 3.2 Other specifications ............................................................................................................................... 8 3.3 Hand calculations .................................................................................................................................. 9 3.4 Results ................................................................................................................................................... 9 3.5 Observations and discussion ................................................................................................................ 10

4 LES1-4 .......................................................................................................................................................... 11 4.1 Assignment .......................................................................................................................................... 11 4.2 Computational domain ........................................................................................................................ 11 4.3 Burner and radiation related specifications.......................................................................................... 12 4.4 Devices ................................................................................................................................................ 13 4.5 Simulation time ................................................................................................................................... 13 4.6 Results ................................................................................................................................................. 14 4.7 Experimental data - simulations results ............................................................................................... 23 4.8 Observations and discussion ................................................................................................................ 24 4.9 General discussion ............................................................................................................................... 25

5 Conclusion.................................................................................................................................................... 27

6 Bibliography ................................................................................................................................................ 28

Appendix A .......................................................................................................................................................... 29 SUB1 Script ...................................................................................................................................................... 29 SUB2 Script ...................................................................................................................................................... 29 LES1-4 Script .................................................................................................................................................... 30

Appendix B .......................................................................................................................................................... 38 Radiation ........................................................................................................................................................... 38 Velocity ............................................................................................................................................................. 50 Temperature ...................................................................................................................................................... 52

1 Introduction This report is made in the intention of describing and presenting results of different individual assignments

carried out within the course VBRF16 – Simulation of Fires in Enclosures, Lund University. The aspects of how

the results came out as they did will be the main target of the discussion inside this report. The report will start

with a presentation of the different assignments, and then a deeper study of each and every one of them.

1.1 Method The assignments included:

Hand calculations of input data for computer simulations.

Hand calculations for results to use as comparisons with computer simulations.

Computer simulations. Program used for this was the computational fluid dynamics(CFD) program,

Fire Dynamics Simulator (FDS), version 6.

Presentation of data results in graphs.

Presentation of results by pictures rendered in the Smokeview(SMV) program, also version 6.

1.2 Description of assignments There were three different assignments, called SUB1, SUB2, LES1-4 which required respectively three, six, and

eight simulations. In this particular report, there had to be three more simulations made within the LES1-4

assignment and two more within the SUB2 assignment. This was required for the sake of comparability between

the different simulations. So in total there were 22 simulations performed. Below there will be a presentation of

the names of each assignment and its simulations, and a description of what they included.

1.2.1 SUB1

A simulation of a free burning plume with a heat release rate of 4850 kW was simulated. The three different

simulations were made with three different grid sizes – coarse, medium and fine. These simulations received the

names:

SUB1 Coarse

SUB1 Medium

SUB1 Fine

1.2.2 SUB2

The simulation included the incident heat flux from one 2x2 meters plate to another parallel plate with the same

area. In this case the distance between the plates were 9 meters and the different simulations were made with

three different grid sizes - coarse, medium and fine, and different radiation angles – min, mid and max. This

assignment required that two extra simulations were done, both with even lower number of angles, presented last

in the following list. The eight different simulations received the names:

SUB2 Coarse MIN

SUB2 Coarse MID

SUB2 Coarse MAX

SUB2 Fine MIN

SUB2 FineMID

SUB2 Fine MAX

SUB2 Fine NEW MIN

SUB2 Coarse NEW MIN

1.2.3 LES1-4

This assignment included simulations of a fire inside an enclosure in the size of a small room. This simulation

was made as comparison of the reality, which was provided through a report of experiments carried out by

[2]

Steckler et al. (1982). Results such as temperature-height and velocity-height in an opening of the room had to

be analyzed. Two different grid sizes (coarse and fine) were used. The assignment included four different sub-

assignments within the same room. In the first there was no radiation turned on in FDS. In the second there was

radiation model turned on. In the third there was also radiation, but the heat release rate was increased by 10%.

In the fourth, there was radiation turned on but the emissivity of the walls was reduced by 50%. After the review

of the reporting sheet of these assignments, there had to be two new simulations made. This was required since

the radiative fraction used didn’t reflect the real radiative fraction of the fuel that was used in the simulations.

Also a simulation with the default value of solid angles was simulated, only for the sake of comparability of the

radiation patterns. The simulations received the names:

LES1 Coarse

LES1 Fine

LES2 Coarse

LES2 Fine

LES3 Coarse

LES3 Fine

LES4 Coarse

LES4 Fine

LES2New Coarse

LES2New Fine

LES2New Coarse MIN

[3]

4

4

11

[m]

2 SUB1 In this chapter the SUB 1 and its eight different simulations will be specified further with focus on the input dat

and the hand calculations that led to the input data. There will also be comparisons made between hand

calculated results and simulations results. The results will be thoroughly discussed in the end of the chapter.

2.1 Computational domain The computational domain was chosen as a vertical room with the base of 4x4

meters and a height of 11 meters, in order to contain the whole flame. For

visualization see Figure 1.

2.1.1 Grid size

The grid sizes were chosen in an unorthodox fashion - the cells were chosen as

non-cubical. The reason for this was the aim of having a

for the different grid sizes, along choosing good mesh cell division numbers in

the I, J and K directions from the manual (McGrattan et al., 2013, p.31), and

also along sticking to the size of the computational domain . This resulted in a

slightly deviating height from the width and depth of the cells, hence the

resulting non-cubical cells.

In order to calculate , the equation (6.1) in the FDS manual was used, along

with standard ambient properties and a HRR of 4850 kW (McGrattan et al.,

2013, p.37).

The result of the different mesh grid sizes can be seen in Table 1.

Table 1. Grid sizes of the meshes used in SUB1.

Direction

Grid sizes [m]

SUB1 Coarse SUB1 Medium SUB1 Fine

X 0,444444444 0,148148148 0,111111111

Y 0,444444444 0,148148148 0,111111111

Z 0,458333333 0,135802469 0,114583333

2.2 Fire The area of the fire had to be of different sizes, due to the different cell sizes. This resulted in a choice of

different HRRPUA in every grid. The fuel used was default – propane. Also the radiation was default, so the

radiative fraction was too (McGrattan et al., 2013). The resulting HRRPUA and burner areas are presented in

Table 2. All of them result in a HRR of 4850 kW which was asked to simulate for the assignment.

Table 2. Burner area and HRRPUA of the different cases.

SUB1 Coarse SUB1 Medium SUB1 Fine

Fire area [m2] 1,777777778 2,19478738 2,086419754

HRRPUA [kW/m2] 2728,125 2209,78125 2324,556212

2.3 Time step As the author of this report was very new to the FDS-program (a novice if you may) when he carried out the

simulations, the time step was calculated manually and specified, which FDS does automatically otherwise. The

used time steps (calculated with equation from FDS manual (McGrattan et al., 2013, p.30)) are:

SUB1Coarse - 0.216128129 s

SUB1 Medium - 0.069269045 s

SUB1 Fine - 0.054032032 s.

Figure 1. Computational domain.

[4]

2.4 Devices The devices consisted of five thermocouples. They were supposed to be placed on 100, 125, 150, 175 and 200

percent of the hand calculated flame height. See following chapter for hand calculations. The first hand

calculated flame height that was used when placing devices in the simulations was wrong, so actually the

thermocouples were instead placed on 96, 120, 144, 168 and 192 percent of the correctly calculated Heskestad

flame height.

2.5 Hand calculations The flame height was calculated with the Heskestad plume equation and the temperatures on the different

heights of interest were calculated with the Heskestad equation for centerline temperature in plumes. Also the

virtual origin was included in the calculations. These equations can be found in the book by Karlsson &

Quintiere (2000).

Since the burner areas were deviating from case to case and it was only one graph sought for in the results, there

had to be made a compromise. This was done by averaging the areas when calculating the hydraulic diameter

required for the flame height equation.

The results of the hand calculations follow in Table 3, in an order of the calculation process.

Table 3. Hand calculated results for plume temperatures.

Average burner area 2.019661637 m2

Hydraulic diameter 1.603593796 m

Heskestad flame height, L. 5.368631404 m

Virtual origin, z0. 0.838192444 m

Height of the measure points in plume

96%

120%

144%

168%

192%

5.158671843 m (also the wrongly calculated flame height)

6.448339804 m

7.738007765 m

9.027675725 m

10.31734369 m

Plume temperatures on the different measure points

96%

120%

144%

168%

192%

433.3208634 oC

281.1856138 oC

199.5296587 oC

150.1463985 oC

117.7748935 oC

[5]

2.6 Results The result of the hand calculated Heskestad temperatures and the temperature of the different heights from the

simulations is shown in Chart 1 below.

Chart 1. Resulting height-dependent temperatures of SUB1.

Results from the simulations via pictures of flame height and examples of pictures that shows turbulences and

temperature gradients in the flame is presented in Figure 2 respectively Figure 3.

Figure 2. Flame heights of the three cases.

4.5

6.5

8.5

10.5

12.5

0 100 200 300 400 500 600

Height [m]

Temperature [C]

Centerline Temperature - Height Above Burner

Heskestad

Coarse

Moderate

Fine

Coarse Medium Fine

[6]

Figure 3. Examples of turbulences and temperature gradients of the three cases.

2.7 Observations and discussion As one can see there is a major difference between all of the results relating to the simulation SUB1 Coarse and

the other cases. The flame height of the coarse case is 3-4 meters. The others are about 5-6 meters. The SUB1

Coarse has a practically laminar flow, whilst the SUB1 Medium has more of a turbulent scheme. And the most

turbulence can be recognized in the SUB1 Fine.

Comparing the SUB1 Coarse temperature-height relation to the others in Chart 1, one can also notice a major

difference. The difference in temperature increases with the height. The higher above the flame the more

difference can be noticed between the SUB1 Coarse and the other cases. At the highest measure point, the

temperature of the SUB1 Coarse is equal to twice the other temperatures. However, in the flame region, the

temperatures are virtually the same. If one study the turbulence in Figure 2, it’s rather easy to give a reason for

this. The turbulence in the SUB1 Coarse case is of a smaller magnitude, thus concentrating the hot gases along

the centerline, resulting in higher temperatures along the measure points than in the rest of the cases.

The lack of turbulence in the SUB1 Coarse case results in a uniformly distributed temperature gradient. This is

not strange at all, since the grid is larger in the coarse case, thus resulting in an averaging of the temperature over

larger volumetric elements.

As one can see from Chart 1, the SUB1 Fine is the one that relates best to Heskestad. With that stated it would be

easy to draw the conclusion that SUB1 Fine is closest to reality. What has to be regarded is that neither

Heskestad nor the SUB1 Fine is the reality. They are only two different but fairly good estimates, and should be

regarded as such. What can be said is that SUB1 Fine has the best results if you compare to the other

simulations, because of its smaller grid size. A smaller grid size is always better, since FDS solves the Navier-

Stokes equations on a larger amount of cells on the same volume, giving a better “resolution” of the results, so to

speak.

It’s not safe to regard even the SUB1 Fine as good enough, since it might be that a simulation with an even finer

grid, could actually give a different result, and therefore a better result. This can be stated since the graphs of the

SUB1 Medium and SUB1 Fine case aren’t similar, especially not in the flame region, where the resulting

Coarse Medium Fine

[7]

temperatures of the two cases are varying with approximately 100 degrees. This is a result of the lack of

representation of the higher turbulence in the flame region (Petterson, 2002).

However, using three different burner areas and thereby three different HRRPUA may have made the different

results less comparable, hence it’s not safe to state that the medium grid is insufficient either. Also, this may be a

very big factor when looking at the coarse case, where the used HRRPUA was about 20 percent higher than in

the other cases.

Another thing contemplating to the worse resolution than expected in the coarse case may be the use of a fixed

time step. Using a fixed time step means that FDS may never adjust it to a better value – we’re stuck with the

default value. This may have resulted in a poor resolution in the time-factor, which means that the results might

have been too much averaged over time. This leads to the loss of too much of the instantaneous movements,

which are so sought for when using large eddy simulations.

Using non-cubic cells might also have negatively influenced the results. To know for sure, another simulation

with cubic sells should be carried through. The reason this being stated as a possible error source is that the

manual says that cubic cells are best (McGrattan et al., 2013, p.31).

[8]

3 SUB2 In this chapter the SUB2 assignment and its eight different simulations will be specified further with focus on the

input data. There will be comparisons made between hand calculated results and simulations results. The results

will be thoroughly discussed in the end of the chapter.

3.1 Computational domain The computational domain was specified as a horizontal corridor with open boundaries, except for the short

vertical sides. These sides, also known as “the plates” from now on, were of an area of 2x2 meters each. The

distance between the plates were specified as 9 meters, see Figure 4.

Figure 4. Computational domain (the plates are squares).

3.1.1 Grid size

The cells in the two meshes that were used were specified as cubic cells, and their dimensions follow below:

SUB2 Coarse – 0.2 meters.

SUB2 Fine – 0.1 meters.

3.2 Other specifications In this subchapter there will be a presentation of all the important specifications made in the script file.

3.2.1 Different solid angles

There were a number of different solid angles specified, in order to see the difference in results of the incident

radiation. These are presented for each of the simulations in Table 4.

Table 4. Solid angles. * - Extra simulations with the default value, made for comparability.

Simulation Number of solid angles

SUB2 Coarse MIN 400

SUB2 Coarse MID 4000

SUB2 Coarse MAX 8000

SUB2 Fine MIN 400

SUB2 FineMID 4000

SUB2 Fine MAX 8000

SUB2 Fine NEW MIN* 104

SUB2 Coarse NEW MIN* 104

3.2.2 Important scenario-specific settings

The temperature of hot plate was specified as 750 OC.

The cold plate had the default starting value of 20 OC.

The chosen output in FDS was incident heat flux.

The emissivity of the hot plate was 0.85.

[m]

[9]

Emissivity of the cold plate: 0.9 (default value, but it doesn’t matter really, since it’s incident heat flux

that’s being measured).

The convective heat transfer was turned off.

A device was placed in the middle of the cold plate, measuring incident heat flux.

The boundaries measured incident heat flux.

Simulation time was specified as 20 seconds, which was enough to reach steady state.

3.3 Hand calculations The hand calculations were an estimate of the same incident heat flux that in the simulations was represented

through a device placed on the cold plate.

The calculations were carried out through the method of a configuration factor. An equation was used, which is

presented in the book by Karlsson & Quintiere (2000), page 162.

The results of the hand calculations follow in Table 5, in an order of the calculation process.

Table 5. Hand calculated configuration factor and resulting incident heat flux.

Configuration factor, FHot plate – point. 0.01546465

Incident heat flux 0.816290273 kW/m2

3.4 Results The results in this subchapter will be presented as pictures of radiation pattern, rendered from the different

simulations and a table of the measured and calculated incident heat fluxes.

Figure 5. Patterns of the incident heat flux from the output of the different SUB2 simulations.

Table 6. Summary of the point value of the incident heat flux for the different simulations and hand calculated values.

Grid Theoretical

value [kW/m2]

NEW MIN

solid angles

[kW/m2]

MIN solid

angles

[kW/m2]

MID solid angles

[kW/m2]

MAX solid angles

[kW/m2]

Coarse 0,81629 0,692258

1,5378146 1,4714528 1,4706916

Finer 0,81629 0.47778720 1,5956477 1,3422738 1.3456397

[10]

3.5 Observations and discussion The results in Figure 2 show that the higher number of solid angles, the more realistic the results look. In the

NEW MIN case you can notice that the highest incident radiation is in the corners of the plates. This is a bad

representation of reality, since the further out from the middle of the plate, the lower the radiation should be.

This also applies for the MIN case. However, the most radiation in the MIN case is targeted in the middle, which

is a better representation. But you cannot say that it’s a good enough representation, since the radiation pattern is

scattered, and you don’t have a fine gradient decreasing with the distance from the middle.

In the MID and MAX cases the results become more representative. Here it becomes possible to state that the

results are a good enough estimate of reality, since they aren’t varying that much when the solid angles are

increased.

Another thing that makes the analyzing of the results more tricky is that; if one takes a look at the MIN cases in

Figure 5, it’s noticeable that using a coarser grid gives a better result, since the pattern looks more realistic. We

have learned that a finer grid always gives a better result, so why is that so?

It’s because the coarse grid requires less solid angles to make a good representation. This is because of the fact

that the coarse cells by the cold plate are in a higher extent (than in the fine case) “hit” by the rays that are

calculated from the cells by the hot plate, through every cell along their ways.

Looking at Table 6, one can see that the NEW MIN case has a lower incident heat flux than the theoretical value,

whilst the other cases have higher values than the theoretical value. But just as in SUB1 the theoretical value

isn’t reality, we’d have to make a full scale experiment to know for sure the correct answer. And then we can say

which result is the best. But even then we’d have to take the convection heat transfer in consideration in the

simulations and calculations.

However, the results in the MID and MAX cases are good, since they are quite insensitive to higher numbers of

solid angles. Even the coarse and fine values of the MID and MAX cases don’t vary much, less than 10 percent

from each other. However, the results might have become even better with use of an even finer grid size, and

most definitely worse with use of a coarser grid.

[11]

4 LES1-4 In this chapter the LES1-4 assignments and their ten different simulations will be specified further with focus on

the input data. There will be comparisons made between results from full scale experimental data (provided by

Steckler et al. (1982)) and simulations results. The results will be thoroughly discussed in the end of the chapter.

4.1 Assignment The assignment consisted of four different cases, simulated with two different grid sizes. The computational

domain consisted of a room with an opening, with a burner along the wall. The different cases were:

LES1 – Simulate the case without radiation model

LES2 – Simulate the case with radiation model

LES3 – Simulate the case with radiation model and 10% increased HRR

LES4 – Simulate the case with radiation model and with a reduced emissivity of the walls by 50%.

There had to be made three extra simulations, in order to achieve comparability between the results. These three

extra simulations referred to the LES2 case and therefore received the names LES2New Coarse/Fine and

LES2New Coarse MIN

As already stated, all the cases had to be simulated with two different grid sizes, the coarse grid with a well-

chosen cell size and the fine one with half the length of the coarse cells, in each dimension. Thus the coarse cases

had a number of N cells and the fine ones had a number of 8N cells.

The burner was placed in in the middle along the wall parallel to the opening. Its fuel according to Steckler et al.

(1982) was methane and the burner had a HRR of 62.9 kW.

4.2 Computational domain The two different computational domains were specified as follows:

&MESH IJK=64,44,44, XB=0.0,4.8,0.0,3.3,0.0,3.3,/ Coarse

&MESH IJK=100,80,80, XB=0.15,3.9,0.15,3.15,0.0,3.0/ Fine.

As one can see, the fine cases had a slightly smaller mesh in order to save computational time.

All boundaries except the floor of the computational domain were specified as open.

4.2.1 Grid size

Looking at the MESH-lines above and using a calculator or using way too much of one’s mental capacity, one

can see that the grid sizes for the coarse and fine cases were specified as 0.075 respectively 0.0375 meters. These

are reasonably good grid sizes, since they are within the range for , suggested by the FDS

manual (McGrattan et al., 2013, p.37).

The characteristic diameter, , was calculated with the equation from the manual (McGrattan et al., 2013, p.37).

With standard ambient properties and a fire HRR of 62.9 kW it resulted in meters.

Choosing the coarse value as resulted in

. So the fine cases had to be

4.2.2 Fire enclosure

As already mentioned the burner was placed inside a room. The dimensions of the room were in the best extent

possible reflecting the ones given in the Steckler et al. (1982) report. Hence to grid fitting the dimensions are not

exactly the same as in Steckler et al. (1982), but they are virtually the same and representing the dimensions

2.8x2.8x2.2 meters. The opening is in form of a window, with the height of 1 meter and the width of 0.75

meters.

[12]

The walls in the room were specified as lightweight concrete and fiber insulation board. This is a fair

approximation, since Steckler et al. (1982) only described the wall materials as lightweight and ceramic fiber

insulation board. The thicknesses of the two materials are specified as the thicknesses given by the experiment.

For a full presentation of the material data, walls and the computational domain see LES1-4 Script, in Appendix.

See Figure 6 for an overview of the computational domain and the enclosure of the coarse cases. The difference

with the fine cases are that the representations of the walls become thinner(since the cells are smaller) and the

volume above and in front of the room is smaller, as mentioned before. Also, more devices are placed in the fine

cases, since it’s interesting to measure values in every cell along an array of cells, when measuring temperature

and velocity profiles.

4.3 Burner and radiation related specifications Since different areas of the burner and different HRRPUA are used in the different coarse and fine cases, it is

important that these are specified. They are presented in Table 7 below. The reason for choosing different burner

areas was the aim at having the fire in the absolute middle of the room in all cases. Unfortunately this may have

resulted in incomparable results; therefore the LES2New had to be simulated with the same burner area, and a

for the fuel appropriate radiative fraction. Also, a presentation of the used number of solid angles for every

simulation is specified in Table 7.

Table 7. Fuel, burner and radiation specifics in different cases.

Simulation Burner area [m2] HRRPUA [kW/m

2] Radiative

fraction

Solid angles

LES1 Coarse 0.09 698.8888889 0.35b -

LES1 Fine 0.06890625 912.8344671 0.35 -

LES2 Coarse 0.09 698.8888889 0.35 4500

LES2 Fine 0.06890625 912.8344671 0.35 3500

LES3 Coarse 0.09 768.77777779a 0.35 4500

LES3 Fine 0.06890625 1004.11791381a 0.35 3500

LES4 Coarse 0.09 698.8888889 0.35 4500

LES4 Fine 0.06890625 912.8344671 0.35 3500

LES2New Coarse 0.09 698.8888889 0.20c 4500

LES2New Fine 0.09 698.8888889 0.20 3500

LES2New Coarse MIN 0.09 698.8888889 0.20 104b

a – The case with 10% increased HRR.

b – Value is default for FDS.

c – From (SFPE, 2002).

Figure 6. LES, computational domain.

[13]

4.4 Devices Devices such as thermocouples with default properties, as well as velocity probes were used. In one of the

corners of the room, about 0.3 meters from the walls there were placed thermocouples, along an array of cells

reaching from the floor to the ceiling. In the middle of the opening, reaching from the lower to the upper bound

of the opening, combined thermocouples and velocity probes were placed. Here also in every cell of the array.

See the green dots in the “Front” image of Figure 6, for a representation of these devices.

4.5 Simulation time The time simulated was different for the coarse and fine cases. Starting out with 3600 seconds with a time shrink

factor of 10, giving steady state at approximately half time resulted in a very unnecessarily time consuming

calculation. Thus having the option to reduce the simulation time to only simulate 1800 seconds in the fine cases

was an obvious choice that was picked, also here with the time shrink factor 10.

To shorten the calculation time further a time step increment was given when specifying the radiation model.

This means that the radiation equations are solved every 10th time step instead of every 3rd step, at the cost of

in a lower resolution of the instantaneously changing radiation patterns in the results (McGrattan et al., 2013).

The coarse cases had increments of 10 and the fine had 20.

Note: The LES3 Fine simulation crashed after about 1200 simulated seconds.

[14]

4.6 Results The results of the LES1-4 will be presented in; charts of height-temperature and height-velocity profiles,

transient conditions of temperature and velocity, pictures rendered from SMV. The presented data of choice in

the different charts intend to make it easier for the reader to follow the comparisons between and discussion of

results from different simulations.

4.6.1 Transient conditions

The transient conditions for the opening, the topmost thermocouples and velocity probes can be seen in

respectively Chart 2 and Chart 3.

0.00

50.00

100.00

150.00

200.00

0 200 400 600 800 1000 1200 1400 1600 1800

Temp [C]

Time [s]

Transiency for topmost opening thermocouple (FINE MESH)

LES1LES2LES3LES4LES2New

0.00

50.00

100.00

150.00

200.00

250.00

0 500 1000 1500 2000 2500 3000 3500

Temp [C]

Time [s]

Transiency for topmost opening thermocouple (COARSE MESH)

Chart 2. Fine and Coarse mesh transient temperature conditions of different cases.

[15]

-0.50

0.00

0.50

1.00

1.50

2.00

0 200 400 600 800 1000 1200 1400 1600 1800

Velocity [m/s]

Time [s]

Transiency for topmost opening probe (FINE MESH) Moving Average

LES1LES2LES3LES4LES2New

-0.50

0.00

0.50

1.00

1.50

2.00

2.50

0 500 1000 1500 2000 2500 3000 3500

Velocity [m/s]

Time [s]

Transiency for topmost opening probe (COARSE MESH) Moving Average

Chart 3. Fine and Coarse mesh transient velocity conditions of different cases.

[16]

4.6.2 Temperature-height profiles

The temperature-height profiles of the corner and the opening will be presented below. Also for each, there will

graphs for comparisons of the profiles between the different grid sizes.

4.6.2.1 The Corner

0

0.5

1

1.5

2

2.5

0.00 50.00 100.00 150.00 200.00

Height [m]

Temperature [C]

FINE Corner temperature profiles

LES1

LES2

LES3

LES4

LES2New

0

0.5

1

1.5

2

2.5

0 50 100 150 200 250

Height [m]

Temperature [C]

COARSE Corner temperature profiles

LES1

LES2

LES3

LES4

LES2New

0

0.5

1

1.5

2

2.5

0.00 50.00 100.00 150.00 200.00 250.00

Height [m]

Temperature [C]

Comparison LES2 and LES2New grid dependence (Corner)

LES2 Coarse

LES2 Fine

LES2New Coarse

LES2New Fine

Chart 4. Coarse and fine corner temperature profiles, with grid dependence comparison.

[17]

4.6.2.2 The opening

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0.00 50.00 100.00 150.00 200.00

Height [m]

Temperature [C]

FINE opening temperature profiles

LES1

LES2

LES3

LES4

LES2New

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 50 100 150 200 250

Height [m]

Temperature [C]

COARSE opening temperature profiles

LES1

LES2

LES3

LES4

LES2New

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0.00 50.00 100.00 150.00 200.00 250.00

Height [m]

Temperature [C]

Comparison LES2 and LES2New grid dependence (opening)

LES2 Coarse

LES2 Fine

LES2New Coarse

LES2New Fine

Chart 5. Coarse and fine opening temperature profiles, with grid dependence comparison.

[18]

4.6.3 Velocity-height profiles

Since the velocities were only measured in the opening, there are only one set of velocity-height profiles, for

graphs, see Chart 6 below.

4.6.4 Smokeview rendered results

The results from SMV will be presented here. That includes radiation patterns and velocity- and temperature

patterns from slices in the middle of the room. A very tenuous part of all pictures rendered in SMV will be

presented in this chapter, the rest can be found in Appendix B. The reason for this is that most of the results are

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

-1.00 -0.50 0.00 0.50 1.00 1.50 2.00

Height [m]

Velocity [m/s]

FINE opening velocity profiles

LES1

LES2

LES3

LES4

LES2New

0

0.5

1

1.5

2

-1.00 -0.50 0.00 0.50 1.00 1.50 2.00 2.50

Height [m]

Velocity [m/s]

COARSE opening velocity profiles

LES1

LES2

LES3

LES4

LES2New

00.20.40.60.8

11.21.41.61.8

-1.00 -0.50 0.00 0.50 1.00 1.50 2.00 2.50

Height [m]

Velocity [m/s]

Comparison LES2 and LES2New grid dependence (opening)

LES2 Coarse

LES2 Fine

LES2New Coarse

LES2New Fine

Chart 6. Coarse and fine opening velocity profiles, with grid dependence comparison.

[19]

to a great extent looking like one another, except that the colorbar scale may vary at mostly + 10 %, given the

approximately same pattern – indicating a possibility of a slight varying of the results.

4.6.4.1 Radiation

Figure 7. Radiation pattern of LES2 Fine.

Figure 8. Radiation pattern of LES2New Fine.

[20]

Figure 9. Radiation pattern of LES2New Coarse.

Figure 10. Radiation pattern of LES2New Coarse MIN.

Figure 11. Radiation pattern of LES4 Fine(reminder: emissivity of walls 50%).

[21]

4.6.4.2 Temperature

Figure 12 Temperature LES 1, coarse and fine (reminder: Radiation model off).

Figure 13. Temperature LES2New, coarse and fine(reminder: radiative fraction 0.2).

Figure 14. Temperature LES3, coarse and fine(reminder: HRR increased by 10%)

COARSE FINE

COARSE FINE

[22]

4.6.4.3 Velocity

Figure 15 Velocity LES 4, coarse and fine.

Figure 16. Velocity LES2NEW, coarse and fine.

COARSE FINE

[23]

4.7 Experimental data - simulations results In order to make comparisons with experimental data, it is wise to present these. This will be done in this

chapter. The results of the experiment will be presented in the same charts as the LES2New Fine simulation

results in order to make the comparisons easier. LES2New Fine was chosen as comparison data since it has the

most correct input data in terms of burner and radiation properties, see chapter 4.3 for explanation. The used

experimental data values are those of test number 622 in Steckler et al. (1982)

00.20.40.60.8

11.21.41.61.8

2

0 20 40 60 80 100 120 140 160 180 200

Height [m]

Temperature [C]

Comparison experimental data and LES2New Fine (opening temperature)

(Steckler et al., 1982)

LES2New Fine

0

0.5

1

1.5

2

2.5

0 20 40 60 80 100 120 140 160 180 200

Height [m]

Temperature [C]

Comparison experimental data and LES2New Fine (Corner temperature)


LES2New Fine

00.20.40.60.8

11.21.41.61.8

2

-1.5 -1 -0.5 0 0.5 1 1.5 2 2.5

Height [m]

Velocity [m/s]

Comparison experimental data and LES2New Fine (opening velocity)


LES2New Fine

Chart 7. Experimental data and LES2New for all measure points

[24]

4.8 Observations and discussion The observations and discussions will reflect back on the results presented. They will be divided in different

subchapters, referring to the subchapters in the results.

4.8.1 Transient conditions

Looking at Chart 2 with transient temperatures, one can notice that the coarse cases have definitely reached

steady state, since the graphs are entirely horizontal. However, looking at the graphs for the fine cases one can

make out a slight increase in temperature over time, thus making it unsafe to regard the fine cases as if they have

entirely reached steady state. This applies especially for LES3 Fine where the simulation crashed at 1200

seconds. The reason that the rest of the fine cases haven’t entirely reached steady state is the fact that they were

only simulated half the time, 1800 instead of 3600 seconds.

In Chart 3 where velocity transiency is presented, one can notice the same tendencies as in the temperature

transience. The differences are that the graphs are more fluctuating, even though every curve has been averaged

with a moving average over 11 point values.

The values of steady state are about 180-200 oC and 1.6-1.8 m/s in the coarse cases, and 170-180

oC 1.2-1.5 m/s

in the fine cases. The only one deviating from this is the LES1 which is visibly lower in both charts.

The uncertainty about transience in the fine cases makes it thinkable that there may be an increase of values

further down the simulation time. So maybe it is inappropriate to compare these results with the results from the

coarse cases just because of the simple reason that they are most likely lower than the steady state values. The

question is how much lower the values of the fine cases are when looking at the grid independence. Another

thing that makes the fine and coarse results inappropriate to compare is the usage of different burner areas and

HRRPUA. Flames with greater areas receive different characteristic than the ones with smaller. An extreme

example is the “Thomas plume” which applies for very large fire areas, which have been found to have other

empirical relations than the traditional cylindrical plume cases (Karlsson & Quintiere, 2000).

The reason for the lower values in the LES1 is what follows when the radiation model is turned off. When the

radiation model is turned off, the HRR of the fire is being decreased with the same value as the radiative

fraction. In this case it was 0.35, which is actually a lot in this case. It is a lot because the radiative fraction

should have been around 0.2 - given the fuel was methane.

4.8.2 Temperature-height profiles

Looking at Chart 4 and Chart 5 one can see that the corner profiles have more bending in their curves than the

ones in the opening. This ought to be because of the concentration of the cold and hot gasses by the

thermocouples placed in the heights above and below the opening, in the corner.

All the LES1 cases have a curve located more to the left, indicating lower temperatures on all measure points

than in the rest of the cases, as they should, because of the turned off radiation model.

Looking at Chart 4 (the corner values) it is clearly visible that the coarse cases have generally higher

temperatures. In some extent this is also visible in Chart 5 (the opening values) although it is not as pronounced

as in chart 4. This may be to some extent because of the transience problem, but more likely the greater part of it

is because that is the way it turns out when using a coarser grid. The tendency that greater grid sizes tend to

generate results with higher temperatures is confirmed in a report by Petterson (2002). Also, looking at the

curves of the fine cases transient conditions, they are very close to steady state, which makes it unlikely that lack

of steady state in the fine results is the reason.

4.8.3 Velocity-height profiles

Chart 6 shows that the velocities inside the opening never extend below -0.95 and never exceed 1.95 m/s. There

is a clear difference between LES1 and the rest cases. LES1 has a more narrow profile, which never extends

beyond the boundaries of any other case. Its neutral plane is higher up than any other simulations, and the curve

is steeper, indicating less spread in velocity over the height. Again it is because of the turned off radiation model

– less HRR indicates lower burning rate and thus a lower production of gasses.

[25]

The coarse cases except LES1 have an irregularity around the height of the neutral plane, which the fine cases do

not have. The fine cases instead have an irregularity along the highest measure point, which is adjacent to the

soffit. This, the coarse cases do not have. An educated guess would be that these irregularities have something to

do with the way FDS handles near-wall flows. One general problem is that no shear stress of the velocity, by the

wall can be recognized, because of the nature the cells. However, this is in FDS resolved using a model called

Werner-Wengle (McGrattan et al., 2013). In this report there is no room to investigate the errors that may be

present using this model. Another simpler reason for the irregularities may be because of insufficient averaging

of the data used for the plots.

Except from the irregularities, the coarse and fine cases are very alike; both in the placement and in the shape of

the curves, see grid comparison in Chart 6.

4.8.4 Smokeview rendered results

Observations of SMV outputs will be presented and discussed below.

4.8.4.1 Radiation

The structures of the different results are almost lookalikes, except for in one case; the LES2New Coarse MIN,

where default value of solid angles were used. Here it is possible, due to the lower number of solid angles, to

distinguish a slight scattering in the pattern, which you cannot see in any other case. The reason for scattering is

explained in the discussion of SUB2.

The thing that distinguishes the cases from one another is a slight variation in the width of the colors in the

gradients, as well as the different numbers set on the boundaries of the color bars. For figures with patterns see

chapter 4.6.4.1 or Appendix B.

4.8.4.2 Temperature

In the temperature slices, the LES1 once again makes itself noticed by deviating from the other results. It has a

clear structure that resembles the stratified case. The LES2-4 and the “new” cases, have higher temperatures in

the whole compartment, which resembles the well mixed case to a greater extent. It is hard to make out

differences between the other results.

For pictures of the temperature slices, see chapter 4.8.4.2 or Appendix B.

4.8.4.3 Velocity

It is hard to notice any difference in the velocity slices. They have the same structures, though the areas of the

different colors may differs a little, indicating a small variation in velocities. LES2New cases have higher values

on its color bar bounds, indicating it may have higher gas velocities. For a velocity comparison one would have

to refer to the charts, the pictures aren’t telling much. Yet, pictures can be seen in chapter 4.6.4.3 or Appendix B.

4.8.5 Experimental data from Steckler et al. (1982)

Looking at Chart 7 one can distinguish even more bent temperature profiles in the experimental data for the

corner than in the simulation results. The opening temperature profiles on the other hand have a strikingly

similar shape. However, the temperatures are higher in the simulations than in the experimental data in both the

corner and the opening. This may be due to insufficient grid convergence, but may also be a result of bad

representation of fuel, wall material and radiation properties.

The velocity profiles are not as alike as the temperature profiles. The experimental data has a wider span of

velocities over the same height. This is contradictive due to the fact that the temperatures in the room were lower

in the experiment, yet still it has higher velocities in both directions.

4.9 General discussion Topics not being fit to discuss in chapter 4.8 will be discussed in this part.

The problem with using wrong radiative fraction in all cases except the “new” ones is that less part of the fire is

producing gasses, thus the results from these simulations aren’t trustworthy enough to compare to the

[26]

experimental data. The more gasses produced the higher the velocities are and ultimately neither the

temperatures nor velocities will be comparable to experimental data. Although they are good for a discussion on

how FDS varies in results with different inputs.

Looking at LES4 results, where the emissivity was reduced, little or no variation from LES2 cases can be seen.

This is indicating that radiation from the heated walls to the gasses isn’t a big factor.

The LES3 results are generally higher in temperature and have wide velocity profiles. This is for the same reason

that the LES1 results are lower and narrower, only it is the other way around.

Using such a high amount of solid angles was not motivated. That is safe to state when looking at the results.

Even the default value of 104 angles gave almost acceptable results. Due to the longer computational time, the

use of many angles leads to compromising in other areas such as the transience.

[27]

5 Conclusion The conclusions derived from the different assignments are:

The mesh of the burner and the burner specifics must be well defined in order to represent:

a. good enough deal of the turbulence structures

b. temperatures that have any correlation with reality

To do this, one has to do several simulations until grid independence is reached.

It is difficult to decide if the radiation model is sufficient, since a coarse grid may generate better results

with fewer solid angles than a fine grid with the same amount of angles. To know if it is sufficient, one has

to make sure that they have:

a. achieved grid independence

b. no scattering in their radiation patterns.

The grid sizes have an impact on the temperatures in the compartment, and thus an impact on the velocities

by the opening. A coarser grid gives a higher temperature, and wider bounds of the velocity profiles.

The radiative fraction is important to specify correctly when trying to achieve reality converging results.

It is important to compensate HRR if turning off radiation model, there will be large differences in the

results and reality otherwise.

Emissivity of the walls has in the LES application little or no effect on the temperature or velocity profiles.

[28]

6 Bibliography Karlsson, B. & Quintiere, J.G., 2000. Enclosure Fire Dynamics. Boca Raton: CRC Press.

McGrattan, K. et al., 2013. NIST Special Publication 1019 Sixth Edition- Fire Dynamics User's Guide. Manual.

Baltimore, Maryland: U.S. Department of Commerce NIST.

Petterson, N.M., 2002. Assessing the Feasibility of Reducing the Grid Resolution in FDS Field Modelling. M.E

Degree thesis. Christchurch, New Zealand: University of Canterbury School of Engineering, University of

Canterbury.

SFPE, 2002. SFPE Handbook of Fire Protection Engineering. 3rd ed. Quincy, Massachusetts: NFPA.

Steckler, K.D., Quintiere, J.G. & Rinkinen, W.J., 1982. Flow Induced by Fire in a Compartment. Washington,

DC: U.S. Department of Commerce National Bureau of Standards.

[29]

Appendix A Deviations in the scripts are notified with different colors.

SUB1 Script SUB 1 Anders Lynnér - Free burning fire temperature measures and comparisons (Standard Combustion model & Fuel)

HRR: 4850

&HEAD CHID='SUB1-Coarse',Title='free burning - 4850 kW Model:Default'/

SUB1-Medium

SUB1-Fine

&MESH IJK=9,9,24, XB=0.0,4.0,0.0,4.0,0.0,11.0/

SUB1-Medium:27,27,81

SUB1-Fine:36,36,96

&TIME T_END=60.0, DT=0.22/

SUB1-Medium:0.069

SUB1-Fine:0.054

&SURF ID='FIRE', HRRPUA=2728.125, COLOR='RASPBERRY'/

&OBST XB= 1.333333333,2.666666667, 1.333333333,2.666666667, 0.0, 0.0, SURF_IDS='FIRE','INERT','INERT'/

SUB1-Medium: 1.481481481,2.962962963, 1.481481481,2.962962963,

SUB1-Fine: 1.444444445,2.888888890, 1.444444445,2.888888890,

&DEVC ID='ThermoCouple 100', XYZ=2.0,2.0,5.158671843, QUANTITY='TEMPERATURE'/





&VENT XB=0.0,0.0,0.0,4.0,0.0, 11.0, SURF_ID='OPEN'/




&VENT XB=0.0,4.0,0.0,4.0,11.0,11.0, SURF_ID='OPEN'/

&SLCF PBY=2.0, QUANTITY='TEMPERATURE'/

&TAIL/

SUB2 Script SUB 2 Anders Lynnér - Radiation Between Plates HotSurfTemp 750, Distance 9m

&HEAD CHID='SUB2-Coarse1',Title='Radiation Between Plates, 750C, 9m'/

SUB2-Coarse-NEWMIN

SUB2-Coarse-MIN

SUB2-Coarse-MAX

SUB2-Fine-NEWMIN

SUB2-Fine-MIN

SUB2-Fine-MID

SUB2-Fine-MAX

&MESH IJK=10,45,10, XB=0.0,2.0,0.0,9.0,0.0,2.0,/

Coarse:10,45,10

Fine:20,90,20

[30]

&TIME T_END=20/

&RADI NUMBER_RADIATION_ANGLES=104/ (NEWMIN)

MIN:400

MID:4000

MAX:8000

&SURF ID='HOT PLATE', TMP_FRONT=750.0, EMISSIVITY=0.85, H_FIXED=0.0, TRANSPARENCY=0.0,

COLOR='RED'/

&SURF ID='COLD PLATE', H_FIXED=0.0/

&OBST XB= 0.0,2.0,0.0,0.0,0.0,2.0, SURF_ID='HOT PLATE'/

&OBST XB= 0.0,2.0,9.0,9.0,0.0,2.0, SURF_ID='COLD PLATE', BNDF_OBST=.TRUE./





&DEVC ID='IHFLUX', QUANTITY='INCIDENT HEAT FLUX', XYZ=1.0,9.0,1.0, IOR=-2/

&BNDF QUANTITY='INCIDENT HEAT FLUX'/

&MISC BNDF_DEFAULT=.FALSE./

&TAIL/

LES1-4 Script Example script

(Marked in red = Fine Mesh, Marked in grey = Coarse Mesh, Turquise =LES2New Coarse/fine,

Black = LES2NewCoarseMIN. The rest of the deviations of the code are resembled as different colors of marking, no

rules apply.

LES 62,9 kW Full window location C

&HEAD CHID='LES1_Coarse' TITLE='ComparisonStecklerC,62.9kW,FullWindow’/ 1_Fine, 2_Coarse, 2_Fine.. etc

&TIME T_END=3600.0, TIME_SHRINK_FACTOR=10.0/ -Cp of MATL reduced by factor 10-

1800

&MESH IJK=64,44,44, XB=0.0,4.8,0.0,3.3,0.0,3.3,/

&MESH IJK=100,80,80, XB=0.15,3.9,0.15,3.15,0.0,3.0/

&OBST XB=0.15,3.15,0.15,3.15,0.0,0.075, COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall-' /GOLV

&OBST XB=0.15,3.15,0.15,3.15,2.25,2.325,COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall+' /TAK

&OBST XB=0.15,0.225,0.15,3.15,0.075,2.25, COLOR='BLUE',TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall-'

/vägg mittemot öppning &OBST XB=0.225,3.075,0.15,0.225,0.075,2.25,COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall+'

/vägg till vänster om öppning facing öppning

&OBST XB=0.225,3.075,3.075,3.15,0.075,2.25,COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall-' /vägg till höger --||--

&OBST XB=3.075,3.15,0.15,3.15,0.075,2.25,COLOR='BLUE',TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall+'

/Dörrvägg &HOLE XB=2.5,3.5,1.275,2.025,0.375,1.725/

&OBST XB=0.1875,3.1125,0.1875,3.1125,0.0,0.0375, COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall-' /GOLV

&OBST XB=0.1875,3.1125,0.1875,3.1125,2.2125,2.25,COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall+'

/TAK &OBST XB=0.1875,0.225,0.1875,3.1125,0.0375,2.2125, COLOR='BLUE',TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall-'

/vägg mittemot öppning

&OBST XB=0.225,3.075,0.1875,0.225,0.0375,2.2125,COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall+' /vägg till vänster om öppning facing öppning

[31]

&OBST XB=0.225,3.075,3.075,3.1125,0.0375,2.2125,COLOR='BLUE', TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall-'

/vägg till höger --||--

&OBST XB=3.075,3.1125,0.1875,3.1125,0.0375,2.2125,COLOR='BLUE',TRANSPARENCY=0.15, SURF_ID='InsulatedLWWall+' /Dörrvägg

&HOLE XB=2.5,3.5,1.275,2.025,0.375,1.725/

&VENT MB='XMAX', SURF_ID='OPEN'/

&VENT MB='XMIN', SURF_ID='OPEN'/

&VENT MB='YMAX', SURF_ID='OPEN'/ &VENT MB='YMIN', SURF_ID='OPEN'/

&VENT MB='ZMAX', SURF_ID='OPEN'/

=============================

=====Corner Devices=====

============================= &DEVC ID='CornerTemp 1 ', XYZ= 2.775,2.775, 0.1125

, QUANTITY='THERMOCOUPLE'/

&DEVC ID='CornerTemp 2 ', XYZ= 2.775,2.775, 0.1875 , QUANTITY='THERMOCOUPLE'/

&DEVC ID='CornerTemp 3 ', XYZ= 2.775,2.775, 0.2625

, QUANTITY='THERMOCOUPLE'/ &DEVC ID='CornerTemp 4 ', XYZ= 2.775,2.775, 0.3375



































========================

=====Window Devices=====

[32]

========================

==VELO==

&DEVC ID='Window,Uvelo 1 ', XYZ= 3.1125, 1.65, 0.4125 , QUANTITY='U-VELOCITY'/

&DEVC ID='Window,Uvelo 2 ', XYZ= 3.1125, 1.65,

0.4875 , QUANTITY='U-VELOCITY'/ &DEVC ID='Window,Uvelo 3 ', XYZ= 3.1125, 1.65,

0.5625 , QUANTITY='U-VELOCITY'/





















==THERM== &DEVC ID='WindowTC 1 ', XYZ= 3.1125, 1.65,

0.4125 , QUANTITY='THERMOCOUPLE'/ &DEVC ID='WindowTC 2 ', XYZ= 3.1125, 1.65,

0.4875 , QUANTITY='THERMOCOUPLE'/

&DEVC ID='WindowTC 3 ', XYZ= 3.1125, 1.65, 0.5625 , QUANTITY='THERMOCOUPLE'/

&DEVC ID='WindowTC 4 ', XYZ= 3.1125, 1.65,




















=======================

[33]

====Corner Devices=====

=======================


















































[34]





























================== ==WINDOW DEVICES==

==================

==Velocity==

&DEVC ID='Window U-Velo 1 ', XYZ= 3.09375,1.65, 0.39375 , QUANTITY='U-VELOCITY'/

&DEVC ID='Window U-Velo 2 ', XYZ= 3.09375,1.65,

0.43125 , QUANTITY='U-VELOCITY'/ &DEVC ID='Window U-Velo 3 ', XYZ= 3.09375,1.65,















[35]
































==Therm==

&DEVC ID='Window U-Temp1 ', XYZ= 3.09375,1.65, 0.39375

, QUANTITY='THERMOCOUPLE'/ &DEVC ID='Window U-Temp2 ', XYZ= 3.09375,1.65, 0.43125


&DEVC ID='Window U- Temp 3 ', XYZ= 3.09375,1.65, 0.46875 , QUANTITY='THERMOCOUPLE'/

&DEVC ID='Window U- Temp4 ', XYZ= 3.09375,1.65, 0.50625

, QUANTITY='THERMOCOUPLE'/ &DEVC ID='Window U- Temp5 ', XYZ= 3.09375,1.65, 0.54375


&DEVC ID='Window U- Temp6 ', XYZ= 3.09375,1.65, 0.58125 , QUANTITY='THERMOCOUPLE'/


0.61875 , QUANTITY='THERMOCOUPLE'/ &DEVC ID='Window U- Temp8 ', XYZ= 3.09375,1.65, 0.65625


&DEVC ID='Window U- Temp9 ', XYZ= 3.09375,1.65, 0.69375 , QUANTITY='THERMOCOUPLE'/

&DEVC ID='Window U- Temp10 ', XYZ= 3.09375,1.65, 0.73125

, QUANTITY='THERMOCOUPLE'/ &DEVC ID='Window U- Temp11 ', XYZ= 3.09375,1.65, 0.76875



[36]

&DEVC ID='Window U- Temp 13 ', XYZ= 3.09375,1.65, 0.84375




, QUANTITY='THERMOCOUPLE'/ &DEVC ID='Window U- Temp 16 ', XYZ= 3.09375,1.65, 0.95625




























============ ====FIRE====

============

&REAC FUEL='METHANE' ID = 'METHANE'

SOOT_YIELD=0.01

IDEAL=.TRUE./ &SURF ID='BURNER', HRRPUA=698.8888889, COLOR='RASPBERRY' /

HRRPUA=912.8344671

HRRPUA=768.77777779 (LES3_Coarse) HRRPUA=1004.11791381 (LES3_Fine)

HRRPUA=698.8888889 (LES 2New, Coarse & Fine)

&OBST XB= 0.225,0.525,1.5,1.8, 0.075, 0.075, SURF_IDS='BURNER','INERT','INERT' / 0.1725,0.435,1.5375,1.8, 0.0375, 0.0375

0.225,0.525,1.5,1.8, 0.075, 0.075 (LES2New Coarse)

0.1725,0.4725,1.5375,1.8375, 0.0375, 0.0375 (LES2New Fine)

=============

==Materials==

============= &MATL ID='LWConcrete'

CONDUCTIVITY=0.15

DENSITY=500.0 SPECIFIC_HEAT=0.1/

[Properties from: Tab 6.1 Enclosure Fire Dynamics, Karlsson & Quintiere]

[37]

&MATL ID='CFIB'

CONDUCTIVITY=0.041 DENSITY=229.0

SPECIFIC_HEAT=2.09/

(CFIB=CeramicFiberInsulationBoard) [Properties from Fiber Insulation Board:Tab 6.1 Enclosure Fire Dynamics, Karlsson & Quintiere]

====================

=Boundary Condition= ====================

&SURF ID='InsulatedLWWall+'

MATL_ID='CFIB','LWConcrete' BACKING='EXPOSED'

COLOR='GRAY'

THICKNESS=0.05,0.15/ EMISSIVITY=0.5

EMISSIVITY_BACK=0.5/ (LES4)

&SURF ID='InsulatedLWWall-'

MATL_ID='LWConcrete','CFIB'

BACKING='EXPOSED' COLOR='GRAY'

THICKNESS=0.15,0.05/

EMISSIVITY=0.5 EMISSIVITY_BACK=0.5/ (LES4)

&BNDF QUANTITY='RADIOMETER'/

=============

====SLICES=== =============

&SLCF PBY=1.65 ,QUANTITY='U-VELOCITY'/

&SLCF PBY=1.65 ,QUANTITY='TEMPERATURE'/

===============

=Radiation OFF= ===============

&RADI RADIATION=.FALSE./ -HRR is now reduced to 40,8850000065 kW- (LES1)

RADI NUMBER_RADIATION_ANGLES=4500.0, TIME_STEP_INCREMENT=20/ -Fewer updates- (LES2,LES3,LES4)

3500 10

RADI NUMBER_RADIATION_ANGLES=4500.0, TIME_STEP_INCREMENT=20, RADIATIVE_FRACTION=0.2/ -Fewer updates-

104.0 10 (LES2New Coarse & Fine)

&TAIL/

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Appendix B This appendix consists of SMV rendered output of radiation, velocity slices and temperature slices.

Radiation

Figure B. 1. Coarse LES2 Floor.

Figure B. 2. Coarse LES2 Walls.

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[40]



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Figure B. 7. Fine LES2 Floor.

Figure B. 8. Fine LES2 Walls.

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[43]



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Figure B. 13. Fine LES2New Floor.

Figure B. 14. Fine LES2New walls.

[45]

Figure B. 15. Coarse LES2New floor

Figure B. 16. Coarse LES2New Walls.

[46]

Figure B. 17. LES2New Coarse Ceiling

Figure B. 18. LES2New Fine Ceiling

[47]

Figure B. 19. LES 2 Ceiling Coarse

Figure B. 20. LES2 Ceiling Fine

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Figure B. 21. Coarse LES3 Ceiling

Figure B. 22. Fine LES3 Ceiling

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Figure B. 23. Coarse LES4 Ceiling

Figure B. 24. Fine LES4 Ceiling

[50]

Velocity

Figure B. 25. Velocity LES1, N and N grid cells.

Figure B. 26. Velocity LES 4, N and 8N grid cells.


Coarse Fine

Coarse Fine

Coarse Fine

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Coarse Fine

Coarse Fine

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Figure B. 30.. Velocity LES2NEW, N and 8N grid cells.

Temperature

Figure B. 31. Temperature LES 1, N and 8N grid cells.

Figure 17 Temperature LES 2, N and 8N grid cells.

Coarse Fine

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Figure B. 34. Temperature LES2New, N and 8N grid cells.

Coarse Fine

Coarse Fine

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