an engineering tool for discharge calculations
TRANSCRIPT
1 PRESLHY dissemination conference, 5-6 May 2021
Pre-normative REsearch for Safe use of Liquid HYdrogen
An engineering tool for discharge
calculations
PRESLHY dissemination conference, 5-6 May 2021, online event
Alexandros Venetsanos, NCSRD
2 PRESLHY dissemination conference, 5-6 May 2021
Outline
− Models
− Implementation
− Validation
− Application
− Conclusions
− Acknowledgements
Models - Implementation - Validation - Application – Conclusions - Acknowledgements
3 PRESLHY dissemination conference, 5-6 May 2021
Models – Physical properties
− Substances: n-H2, p-H2, CH4, H20, CO2, NH3
− EoS: HFE, 3rd-order RKMC, Abel-Noble, Ideal gas
− Phase change: HEM and various HNEM
− Spinodal line calculations
− Various state definition modes (P,T,x) or (P,h) or (P,s) or (P,ρ) etc. +
Multiple states definition from files
− States visualization on TS, PT and PV charts
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
4 PRESLHY dissemination conference, 5-6 May 2021
Models – Release calcs
− Storage Tank
− Either:
− Given tank: (real rank stagnation conditions with time from files) OR
− Modelled tank: Transient mass + energy balance (either entropy or
internal energy) with / without wall heat transfer + thermal equilibrium +
homogeneous or stratified conditions + release from top or bottom
− Isentropic change from tank stagnation state to discharge line inlet
− Discharge line
− Discharge line composed of a user defined number of pipe elements with
discretization for each element + High resolution near min cross section line
where Ma = 1 is expected.
− Steady momentum equation with friction, area change, extra resistances
(fittings) + energy equation with / without wall heat transfer.
− Fictitious nozzle
− 7 different models from literature
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
5 PRESLHY dissemination conference, 5-6 May 2021
Implementation
− Numerics
− Brent’s iterative root finding algorithms
− Golden section min-maximization algorithms
− PIF algorithm for choked flow calculations (Ma = 1 is output not input
condition).
− Machine precision (10-16)
− Simulation time: few seconds for PIF algorithm and order of minutes for a full
blow-down.
− Programming
− Fortran dynamic link libraries
− Python interface (using ctypes+tkinter)
− Early version implemented in NetTools / eLab
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
https://www.youtube.com/watch?v=3iTAt3HdAWI
6 PRESLHY dissemination conference, 5-6 May 2021
Validation (1/5)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
NASA CLH2 critical flow experiments (22 tests) with elliptical
converging-diverging nozzle @ P0 = 12.9-58.9 bar, T0 = 27.2-32.3 K
Simoneau and Hendricks (1979).
Venetsanos, Homogeneous non-equilibrium two-phase choked flow modelling, Int. J. of Hydrogen
Energy, 43 (2018), 22715-22726
P0=12.9bar, T0=30.7K
7 PRESLHY dissemination conference, 5-6 May 2021
Validation (2/5)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
Super Moby Dick experiments for liquid water,@ 20 bar, 212.3 C,
Jeandey et al., Report TT-163, (1981),
CEA, Grenoble.
Venetsanos, Choked two-phase flow with account of discharge line effects, ICHS-8, 2019
8 PRESLHY dissemination conference, 5-6 May 2021
Validation (3/5)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
INERIS CGH2 experiments, @ 900 bar, ambient temperature
25 dm³ type-IV tank, 10 m line, 10mm ID ending to a 2 mm ID nozzle
Proust et al., IJHE, (2011)
Venetsanos et al., Cryogenic and ambient gaseous hydrogen blowdown with discharge line effects,
ICHS-9, 2021
9 PRESLHY dissemination conference, 5-6 May 2021
Validation (4/5)
Models - Implementation - Validation - Application - Conclusions - Closure
DISCHA CGH2 experiments, @ 200 bar, cold (80 K) and warm
(ambient temp.), 2.815 dm³ steel tank, 39 cm line, 9 mm ID ending to
0.5, 1, 2 and 4 mm ID nozzles,
Friedrich et al. PRESLHY D3.4 (2019)
Venetsanos et al., Cryogenic and ambient gaseous hydrogen blowdown with discharge line effects,
ICHS-9, 2021
10 PRESLHY dissemination conference, 5-6 May 2021
Validation (5/5)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
HSE LH2 experiments, @ 2 and 6 bara (sub-cooled),
23 m line, 1 inch ID and 1, 1/2, 1/4 inch ID nozzles
Lyons et al. PRESLHY D3.6 (2020)
Venetsanos et al., Discharge modeling of large scale LH2 experiments with an engineering tool,
ICHS-9, 2021
Nozzle
diameter
(mm)
2 bara 6 bara
Const
densityHNEM HEM
Const
densityHNEM HEM
25.4 3.4 3.3 1.9 9.0 8.5 7.1
12.7 11.6 11.5 7.9 0.1 -0.3 -3.3
6.35 13.4 12.7 9.6
Relative error (%) between predicted and experimental mass flow
rate (positive for overestimation)
11 PRESLHY dissemination conference, 5-6 May 2021
Application – HFE versus ABN (1/3)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
Abel-Noble (ABN) implemented with cp(T) of ideal gas and ABN
enthalpy both at stagnation and nozzle.
P (bar) HFE Abel-Noble Error %
10 618.49 618.25 -0.04
100 6125.72 6105.03 -0.34
200 12112.90 12046.82 -0.55
350 20819.48 20680.72 -0.67
500 29198.51 29011.84 -0.64
700 39891.43 39700.58 -0.48
900 50087.74 49963.19 -0.25
1000 55017.12 54949.99 -0.12
P (bar) HFE Abel-Noble Error %
10 1126.31 1113.99 -1.09
100 11738.09 10736.63 -8.53
200 23383.71 20697.64 -11.49
350 38885.18 34494.43 -11.29
500 52267.89 47203.46 -9.69
700 67834.88 62829.07 -7.38
900 81611.04 77259.51 -5.33
1000 87998.65 84103.33 -4.43
T=100 K
T=298.15 K
Choked conditions (orange dots)
Stagnation conditions (blue dots)
12 PRESLHY dissemination conference, 5-6 May 2021
Application – Discharge line effects (2a/3)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
• Line length effect
• Nozzle size effect
Predicted H2 mass flow rate (HFE EoS)
13 PRESLHY dissemination conference, 5-6 May 2021
Application – Discharge line effect (2b/3)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
Distribution of physical variables along the 15m line, 4mm ID line, 700bar, 280 K
HFE, EoS
14 PRESLHY dissemination conference, 5-6 May 2021
Application – Fictitious nozzle (3/3)
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
Model
idMach=1
Momentum
balanceAdiabatic
Ambient
temperatureIsothermal Isentropic
1
2
3
4
5
6
7
7 fictitious nozzle models
Venetsanos et al., PRESLHY D3.1 (2019)
Stagnation (S) P=100 bar, T=293.15, 80 and 50 K, Nozzle (N)
15 PRESLHY dissemination conference, 5-6 May 2021
Conclusions / Future work
− The developed tool can be applied for:
− Consequence assessment (input to dispersion codes)
− Design of experiments / systems
− Research / Education
− Future work topics
− Further validation
− HNEM modeling
− Tank heat transfer
− Boiling heat transfer (tank+line)
− Two-layer two-phase tank modeling
− Interface + algorithms optimization
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
16 PRESLHY dissemination conference, 5-6 May 2021
The PRESLHY project has received funding from the Fuel Cells and
Hydrogen 2 Joint Undertaking under the European Union’s Horizon 2020
research and innovation program under the grant agreement No 779613.
Models - Implementation - Validation - Application - Conclusions - Acknowledgements
Acknowledgement