theory 1 27 forfabrication and analysis of “mist fan”

FABRICATION AND ANALYSIS OF MIST FAN

CHAPTER-1INTRODUCTION

Misting systems work by forcing water via a high pressure pump and tubing through a brass

and stainless steel mist nozzle that has an orifice of about 5 micrometers, thereby producing a

micro-fine mist. The water droplets that create the mist are so small that they instantly flash

Evaporate. Flash evaporation can reduce the surrounding air temperature by as much as 35 °F

(20 °C) in just seconds. For patio systems, it is ideal to mount the mist line approximately 8 to 10

feet (2.4 to 3.0 m) above the ground for optimum cooling. Misting is used for applications such

as flowerbeds, pets, livestock, kennels, insect control, odor control, zoos, veterinary clinics,

cooling of produce, and greenhouses.

1.1 MIST FAN:

On a hot summer's day, a misting fan can be your best friend. It works on the same principle

of a humidifier. A fan blows a fine mist of water into the air and if the air isn't humid,

the mist evaporates, taking heat from the air with it. This allows the misting fan to work like an

air cooler. In a dry climate, a misting fan can work very well outdoor. Misting fans come in

many different styles, from industrial strength, to small portable battery-operated fans that

consist of an electric fan and a hand-operated water spray pump. You will want a larger model to

get any sort of benefit. They use the cooling power of evaporating water, so they are all natural

and good for the environment.

Use of misting fan

At home: Of course this is the logical choice. Think of how nice it will be to have a misting

fan at home, helping you cool when the weather begins to heat up. With it forecasted to be the

hottest summer on record this year, having a misting fan can be a cheap alternative to an air

conditioner, especially in terms of the energy being used.

Festivals: If you are hosting a festival, you want people to be comfortable. Well-placed misting fans on a hot summer day can become the most popular attraction of the festival, and there may be line-ups to enjoy them.

NRCM,Department of Mechanical Engineering 1


Sports: Any time you have outdoor sports, you have people sitting for long periods of time watching. Having a misting fan on-hand can help keep them cool, and help protect them from the dangers of heat stroke and dehydration

Pool Parties: While being in the pool is great to cool off; sometimes sitting by the pool is nice. To make the experience even nicer, you can have a misting fan set up so that your guests who aren’t in the pool, are still enjoying the cooling feeling of water on their bodies.

Benefits

The heat is not just uncomfortable, it is downright dangerous. In 2003, Europe had its hottest summer since 1540. During that summer, when temperatures reached record levels, 70,000 people died from the heat. In France, they had seven days of 40ºC temperature, something never seen there, resulting in 14,000 deaths.

Having a convenient way to cool is important. Humans sweat, and that sweat forms beads on our skin. When a breeze passes over that, it cools the water and helps us cool down. This is why something like a misting fan can be so important. It creates beads of cool water in the air, which falls on those around it, helping keep them cool without having to use the energy of an air conditioner. So, who can benefit from having a misting fan?

Children: Protecting your children is important and when they are playing outside, having a misting fan will keep them cool when the temperature begins to rise. Sometimes children forget to get something to drink when they are having fun, and that can lead to health problems such as dehydration. To prevent that from happening, have them play near a misting fan, so they can keep cool and hydrated while they play.

Pets: Your pets don’t sweat like you do. For example, dogs burn heat off their bodies by panting, or through their paws. This is why it is important that you have a misting fan set up for your outside pets, along with water bowls and shade. That way, they can keep cool and comfortable, and you won’t have to worry about.

Them becoming ill or even dying from the heat. The same goes for horses. While horses do sweat, you can have a misting fan set up in the horse stables so that while your horses are resting, they are keeping cool.

Workers: If you have employees outside, or in a warehouse where the temperature can get high, having a misting fan will protect those people. It also keeps workers comfortable. A comfortable person is a person who is productive. Any time workers are battling the heat, they are not doing their job at full capacity, and that is going to cost additional money.



BASIC PRINCIPLE:

Misting fan reduces the temperature of air using the principle of evaporative cooling,

unlike typical air conditioning systems which use vapor-compression refrigeration or

absorption refrigerator. It is the addition of water vapor into air, which causes a lowering of

the temperature of the air. The other principle of this system is that the cold water flows into

the environment that absorbs the heat from the hot air and it maintain the cool temperature as

compare to other place.

CHAPTER-2



LITERATURE REVIEW

Misting systems work by forcing water via a high pressure pump and tubing through a brass and stainless steel mist nozzle that has an orifice of about 5 micrometres, thereby producing a micro-fine mist. The water droplets that create the mist are so small that they instantly flash evaporate. Flash evaporation can reduce the surrounding air temperature by as much as 35 °F (20 °C) in just seconds. For patio systems, it is ideal to mount the mist line approximately 8 to 10 feet (2.4 to 3.0 m) above the ground for optimum cooling. Misting is used for applications such as flowerbeds, pets, livestock, kennels, insect control, odor control, zoos, veterinary clinics, cooling of produce, and greenhouses.

Evaporative coolers lower the temperature of air using the principle of evaporative cooling, unlike typical air conditioning systems which use vapor-compression refrigeration or absorption refrigerator. Evaporative cooling is the addition of water vapor into air, which causes a lowering of the temperature of the air. The energy needed to evaporate the water is taken from the air in the form of sensible heat, which affects the temperature of the air, and converted into latent heat, the energy present in the water vapor component of the air, whilst the air remains at a constant enthalpy value. This conversion of sensible heat to latent heat is known as an adiabatic process because it occurs at a constant enthalpy value. Evaporative cooling therefore causes a drop in the temperature of air proportional to the sensible heat drop and an increase in humidity proportional to the latent heat gain. Evaporative cooling can be visualized using a psychrometric chart by finding the initial air condition and moving along a line of constant enthalpy toward a state of higher humidity.

A simple example of natural evaporative cooling is perspiration, or sweat, secreted by the body, evaporation of which cools the body. The amount of heat transfer depends on the evaporation rate, however for each kilogram of water vaporized 2,257 kJ of energy (about 890 BTU per pound of pure water, at 95 °F (35 °C)) are transferred. The evaporation rate depends on the temperature and humidity of the air, which is why sweat accumulates more on humid days, as it does not evaporate fast enough.

The term bacteria as used herein, is a chemical agent which prevents multiplication of bacteria. Evaporative coolers have heretofore employed hygroscopic evaporative cooler pads such as those made of wood excelsior and have utilized recirculating pumps to pump water drained from the pads back to an elevated position at the upper portions of the pad so that water 'is continuously used. In such evaporative coolers, bacteria tends to grow during warm weather and create serious problems. One unpleasant conditon arises when the bacteria multiplies to such an extent that the cool air is laden with bacteria and unpleasant due to the odor of the bacteria. Accordingly, it is an object of the invention to provide a bacteria proof evaporative cooler having hygroscopic pads which are treated with a bacteriostat which prevents the multiplication of bacteria in an evaporative cooler.


https://en.wikipedia.org/wiki/Perspiration

https://en.wikipedia.org/wiki/Psychrometric_chart

https://en.wikipedia.org/wiki/Adiabatic_process

https://en.wikipedia.org/wiki/Enthalpy

https://en.wikipedia.org/wiki/Latent_heat

https://en.wikipedia.org/wiki/Sensible_heat

https://en.wikipedia.org/wiki/Absorption_refrigerator

https://en.wikipedia.org/wiki/Vapor-compression_refrigeration

https://en.wikipedia.org/wiki/Vapor-compression_refrigeration

https://en.wikipedia.org/wiki/Flash_evaporation

https://en.wikipedia.org/wiki/Micrometre


Another object of the invention is to provide an evaporative cooler wherein the evaporative cooler pads are treated with a bacteriostat and operated at a relative humidity of 75 percent or greater, thereby causing the bacteriostat to become sufficiently active to kill bacteria. Understanding evaporative cooling performance requires an understanding of psychrometrics. Evaporative cooling performance is variable due to changes in external temperature and humidity level. A residential cooler should be able to decrease the temperature of air by 3 to 4 °C(or in Fahrenheit scale by 5 to 7 °F).

It is simple to predict cooler performance from standard weather report information. Because weather reports usually contain the dewpoint and relative humidity, but not the wet-bulb temperature, a psychrometric chart or a simple computer program must be used to compute the wet bulb temperature. Once the wet bulb temperature and the dry bulb temperature are identified, the cooling performance or leaving air temperature of the cooler may be determined. For direct evaporative cooling, the direct saturation efficiency, measures in what extent the temperature of the air leaving the direct evaporative cooler is close to the wet-bulb temperature of the entering air.

A nozzle is a device designed to control the direction or characteristics of a fluid flow (especially to increase velocity) as it exits (or enters) an enclosed chamber or pipe. A nozzle is often a pipe or tube of varying cross sectional area, and it can be used to direct or modify the flow of a fluid (liquid or gas). Nozzles are frequently used to control the rate of flow, speed, direction, mass, shape, and/or the pressure of the stream that emerges from them. In a nozzle, the velocity of fluid increases at the expense of its pressure energy.


https://en.m.wikipedia.org/wiki/Gas

https://en.m.wikipedia.org/wiki/Liquid

https://en.m.wikipedia.org/wiki/Pipe_(material)

https://en.m.wikipedia.org/wiki/Fluid

http://research.omicsgroup.org/index.php/Psychrometric_chart

http://research.omicsgroup.org/index.php/Relative_humidity

http://research.omicsgroup.org/index.php/Dewpoint

http://research.omicsgroup.org/index.php/Psychrometrics


CHAPTER-3DESIGN AND FABRICATION

3.1 DESIGN OF MIST FAN:

Fig 1 line diagram of mist fan

The working of mist fan is very simple. The suction pipe is connected with the collecting

tank which takes the water from the tank, and delivers it to the nozzle by the delivery pipe. The

nozzle is inserted at end of the delivery pipe by which water is passes with high velocity and

discharged water and gives fine spray toward direction of air flow, the air flow with high

velocity is strike the water droplet and sprinkle it to the surrounding in the form of mist and cool

the environment.

3.2PERFORMANCE OF MIST FAN:

The mist fan performance requires an understanding of psychometrics. It performance is

variable due to changes in external temperature and humidity level. A residential fan should

be able to decrease the temperature of air by 3 to 4 °C(or in Fahrenheit scale by 5 to 7 °F). It

is simple to predict mist fan performance from standard weather report information. Because

weather reports usually contain the dew point and relative humidity, but not the wet-bulb



temperature, a Psychometric chart or a simple computer program must be used to compute

the wet bulb temperature.

3.3 EQUIPMENT OF MIST FAN

Table no:1

SL.NO. NAME OF THE EQUIPMENTS

1 Collecting tank

2 Centrifugal pump

3 Pipe

4 Nozzle

5 Regulator

6 Electric fan

3.3.1 COLLECTING TANK:

In the water collecting tank, the fresh water in the tank whose capacity (10 -20 lit) of

water. The size of collecting tank is in any shape such as rectangle, square, cylindrical etc. In the

tank there should not be any leakage.

3.3.2 PUMP:A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by

mechanical action. Pumps can be classified into three major groups according to the method they

use to move the fluid: direct lift, displacement, and gravity pumps.

Pumps operate by some mechanism (typically reciprocating or rotary), and

consume energy to perform mechanical work by moving the fluid. Pumps operate via many

energy sources, including manual operation, electricity, engines, or wind power, come in many

sizes, from microscopic for use in medical applications to large industrial pumps.

Mechanical pumps serve in a wide range of applications such as pumping water from

wells, aquarium filtering, pond filtering and aeration, in the car industry for water-

cooling and fuel injection, in the energy industry for pumping oil and natural gas or for

operating cooling towers. In the medical industry, pumps are used for biochemical processes in



developing and manufacturing medicine, and as artificial replacements for body parts, in

particular the artificial heart and penile prosthesis.

3.4 DIFFERENT TYPES OF PUMP:

Positive displacement pumps Impulse pumps Velocity pumps Gravity pumps

3.4.1 Positive displacement pumps :

A positive displacement pump makes a fluid move by trapping a fixed amount and

forcing (displacing) that trapped volume into the discharge pipe.

Some positive displacement pumps use an expanding cavity on the suction side and a decreasing

cavity on the discharge side. Liquid flows into the pump as the cavity on the suction side

expands and the liquid flows out of the discharge as the cavity collapses. The volume is constant

through each cycle of operation.


https://en.wikipedia.org/wiki/Pump#Gravity_pumps

https://en.wikipedia.org/wiki/Pump#Velocity_pumps

https://en.wikipedia.org/wiki/Pump#Impulse_pumps

https://en.wikipedia.org/wiki/Pump#Positive_displacement_pump


Fig. 2 Centrifugal pump

Positive displacement types :

A positive displacement pump can be further classified according to the mechanism used to

move the fluid:

Rotary-type positive displacement

Reciprocating-type positive displacement

Linear-type positive displacement

A simple type of rotary pump where the liquid is pushed between two gears.


https://en.wikipedia.org/wiki/Pump#Positive_displacement_pump


Rotary vane pumps:

Similar to scroll compressors, these have a cylindrical rotor encased in a similarly

shaped housing. As the rotor orbits, the vanes trap fluid between the rotor and the casing,

drawing the fluid through the pump.

Reciprocating positive displacement pumps:

Reciprocating pumps move the fluid using one or more oscillating pistons, plungers, or

membranes (diaphragms), while valves restrict fluid motion to the desired direction.

Pumps in this category range from simplex, with one cylinder, to in some

cases quad (four) cylinders, or more. Many reciprocating-type pumps are duplex (two)

or triplex (three) cylinder. They can be either single-acting with suction during one direction of

piston motion and discharge on the other, or double-acting with suction and discharge in both

directions. The pumps can be powered manually, by air or steam, or by a belt driven by an

engine.

This type of pump was used extensively in the 19th century—in the early days of steam

propulsion—as boiler feed water pumps. Now reciprocating pumps typically pump highly

viscous fluids like concrete and heavy oils, and serve in special applications that demand low

flow rates against high resistance. Reciprocating hand pumps were widely used to pump water

from wells. Common bicycle pumps and foot pumps for inflation use reciprocating action.

Gear pump:

This is the simplest of rotary positive displacement pumps. It consists of two meshed

gears that rotate in a closely fitted casing. The tooth spaces trap fluid and force it around the

outer periphery. The fluid does not travel back on the meshed part, because the teeth mesh

closely in the center. Gear pumps see wide use in car engine oil pumps and in various hydraulic

power packs.

NRCM,Department of Mechanical Engineering10


Fig.4 Gear pump

Screw pump:

A screw pump is a more complicated type of rotary pump that uses two or three screws

with opposing thread — e.g., one screw turns clockwise and the other counterclockwise. The

screws are mounted on parallel shafts that have gears that mesh so the shafts turn together and

everything stays in place. The screws turn on the shafts and drive fluid through the pump. As

with other forms of rotary pumps, the clearance between moving parts and the pump's casing is

minimal.

Fig.5 Screw pump



Progressing cavity pump:

Widely used for pumping difficult materials, such as sewage sludge contaminated with

large particles, this pump consists of a helical rotor, about ten times as long as its width. This can

be visualized as a central core of diameter x with, typically, a curved spiral wound around of

thickness half x, though in reality it is manufactured in single casting. This shaft fits inside a

heavy duty rubber sleeve, of wall thickness also typically x. As the shaft rotates, the rotor

gradually forces fluid up the rubber sleeve. Such pumps can develop very high pressure at low

volumes.

Fig.6 Progressive cavity pump

3.4.2 Impulse pumps:

Impulse pumps use pressure created by gas (usually air). In some impulse pumps the gas

trapped in the liquid (usually water), is released and accumulated somewhere in the pump,

creating a pressure that can push part of the liquid upwards.



Conventional impulse pumps include:

Hydraulic ram pumps – kinetic energy of a low-head water supply is stored temporarily

in an air-bubble hydraulic accumulator, then used to drive water to a higher head.

Pulse pumps – run with natural resources, by kinetic energy only.

Airlift pumps – run on air inserted into pipe, which pushes the water up when bubbles

move upward

Instead of a gas accumulation and releasing cycle, the pressure can be created by burning

of hydrocarbons. Such combustion driven pumps directly transmit the impulse form a

combustion event through the actuation membrane to the pump fluid. In order to allow this direct

transmission, the pump needs to be almost entirely made of an elastomer (e.g. silicone rubber).

Hence, the combustion causes the membrane to expand and thereby pumps the fluid out of the

adjacent pumping chamber. The first combustion-driven soft pump was developed by ETH

Zurich.

Hydraulic ram pumps:

A hydraulic ram is a water pump powered by hydropower.

It takes in water at relatively low pressure and high flow-rate and outputs water at a higher

hydraulic-head and lower flow-rate. The device uses the water hammer effect to develop

pressure that lifts a portion of the input water that powers the pump to a point higher than where

the water started.

The hydraulic ram is sometimes used in remote areas, where there is both a source of

low-head hydropower, and a need for pumping water to a destination higher in elevation than the

source. In this situation, the ram is often useful, since it requires no outside source of power other

than the kinetic energy of flowing water.

3.4.3 Velocity pumps:

A centrifugal pump uses an impeller with backward-swept arms.

Rotodynamic pumps (or dynamic pumps) are a type of velocity pump in which kinetic

energy is added to the fluid by increasing the flow velocity. This increase in energy is

converted to a gain in potential energy (pressure) when the velocity is reduced prior to or as



the flow exits the pump into the discharge pipe. This conversion of kinetic energy to pressure

is explained by the First law of thermodynamics, or more specifically by Bernoulli's

principle. Dynamic pumps can be further subdivided according to the means in which the

velocity gain is achieved.

These types of pumps have a number of characteristics:

1. Continuous energy

2. Conversion of added energy to increase in kinetic energy (increase in velocity)

3. Conversion of increased velocity (kinetic energy) to an increase in pressure head

A practical difference between dynamic and positive displacement pumps is how they

operate under closed valve conditions. Positive displacement pumps physically displace fluid, so

closing a valve downstream of a positive displacement pump produces a continual pressure build

up that can cause mechanical failure of pipeline or pump. Dynamic pumps differ in that they can

be safely operated under closed valve conditions (for short periods of time).

Radial-flow pumps:

Such as pump is also referred to as a centrifugal pump. The fluid enters along the axis or

center, is accelerated by the impeller and exits at right angles to the shaft (radially); an example

is the centrifugal fan, which is commonly used to implement a vacuum cleaner. Generally, a

radial-flow pump operates at higher pressures and lower flow rates than an axial- or a mixed-

flow pump.

Axial-flow pumps:

These are also referred to as all fluid pumps. The fluid is pushed outward or inward and

move fluid axially. They operate at much lower pressures and higher flow rates than radial-flow

(centripetal) pumps.

Mixed-flow pumps:

Mixed-flow pumps function as a compromise between radial and axial-flow pumps. The

fluid experiences both radial acceleration and lift and exits the impeller somewhere between

0 and 90 degrees from the axial direction. As a consequence mixed-flow pumps operate at

higher pressures than axial-flow pumps while delivering higher discharges than radial-flow



pumps. The exit angle of the flow dictates the pressure head-discharge characteristic in

relation to radial and mixed-flow.

3.4.4 Gravity pumps:

Gravity pumps include the Syphon and Heron's fountain. The hydraulic ram is also

sometimes called a gravity pump; in a gravity pump the water is lifted by gravitational force.

3.5 APPLICATIONS:

Pumps are used throughout society for a variety of purposes. Early applications includes

the use of the windmill or watermill to pump water. Today, the pump is used for irrigation, water

supply, gasoline supply, air conditioning systems, refrigeration (usually called a compressor),

chemical movement, sewage movement, flood control, marine services, etc.

Because of the wide variety of applications, pumps have a plethora of shapes and sizes:

from very large to very small, from handling gas to handling liquid, from high pressure to low

pressure, and from high volume to low volume.

3.6 NOZZLE:

A nozzle is a device designed to control the direction or characteristics of a fluid flow

(especially to increase velocity) as it exits (or enters) an enclosed chamber or pipe.

A nozzle is often a pipe or tube of varying cross sectional areas, and it can be used to

direct or modify the flow of a fluid (liquid or gas). Nozzles are frequently used to control the rate

of flow, speed, direction, mass, shape, and/or the pressure of the stream that emerges from them.

In a nozzle, the velocity of fluid increases at the expenses of its pressure energy.



3.7 TYPES OF NOZZLE:

3.7.1 Jet nozzle

3.7.2 High velocity nozzle

3.7.3 Magnetic nozzle

3.7.4 Spray nozzle

3.7.5 Propelling nozzle

3.7.6 Shaping nozzle

3.7.1 Jet nozzle:

A gas jet, fluid jet, or hydro jet is a nozzle intended to eject gas or fluid in a coherent

stream into a surrounding medium. Gas jets are commonly found in gas stoves, ovens, or

barbecues. Gas jets were commonly used for light before the development of electric light. Other

types of fluid jets are found in carburetors, where smooth calibrated orifices are used to regulate

the flow of fuel into an engine, and in jacuzzis or spas.

Another specialized jet is the laminar jet. This is a water jet that contains devices to smooth out

the pressure and flow, and gives laminar flow, as its name suggests. This gives better results

for fountains.

The foam jet is another type of jet which uses foam instead of a gas or fluid.

Nozzles used for feeding hot blast into a blast furnace or forge are called tuyeres.

Jet nozzles are also use in large rooms where the distribution of air via ceiling diffusers is

not possible or not practical. Diffuser that uses jet nozzles are called jet diffuser where it will be

arranged in the side wall areas in order to distribute air. When the temperature difference

between the supply air and the room air changes, the supply air stream is deflected upwards, to

supply warm air, or downwards, to supply cold air.



Fig. 7 Jet nozzle

3.7.2 High velocity nozzle:

Frequently, the goal of a nozzle is to increase the kinetic energy of the flowing medium at

the expense of its pressure and internal energy.

Nozzles can be described as convergent (narrowing down from a wide diameter to a smaller

diameter in the direction of the flow) or divergent (expanding from a smaller diameter to a larger

one). A de Laval nozzle has a convergent section followed by a divergent section and is often

called a convergent-divergent nozzle ("con-di nozzle").

Convergent nozzles accelerate subsonic fluids. If the nozzle pressure ratio is high enough,

then the flow will reach sonic velocity at the narrowest point (i.e. the nozzle throat). In this

situation, the nozzle is said to be choked.

Increasing the nozzle pressure ratio further will not increase the throat Mach

number above one. Downstream (i.e. external to the nozzle) the flow is free to expand to

supersonic velocities; however Mach 1 can be a very high speed for a hot gas because

the speed of sound varies as the square root of absolute temperature. This fact is used

extensively in rocketry where hypersonic flows are required and where propellant mixtures

are deliberately chosen to further increase the sonic speed.

Divergent nozzles slow fluids if the flow is subsonic, but they accelerate sonic or

supersonic fluids.



Convergent-divergent nozzles can therefore accelerate fluids that have choked in the

convergent section to supersonic speeds. This CD process is more efficient than allowing a

convergent nozzle to expand supersonically externally. The shape of the divergent section also

ensures that the direction of the escaping gases is directly backwards, as any sideways

component would not contribute to thrust.

3.7.3 Magnetic nozzle:

Magnetic nozzles have also been proposed for some types of propulsion, such as VASIMR, in

which the flow of plasma is directed by magnetic fields instead of walls made of solid matter.

Fig. 8 Magnetic nozzle



3.7.4 Spray nozzle:

Many nozzles produce a very fine spray of liquids.

Atomizer nozzle are used for spray painting, perfumes, carburetors for internal

combustion engines, spray on deodorants, antiperspirants and many other similar uses.

Air-Aspirating Nozzle uses an opening in the cone shaped nozzle to inject air into a

stream of water based foam to make the concentrate "foam up". Most commonly found

on foam extinguishers and foam hand lines.

Swirl nozzles inject the liquid in tangentially, and it spirals into the center and then exits

through the central hole. Due to the vortexing this causes the spray to come out in a cone

shape.

Fig.9 Spray nozzle



3.7.5 Propelling nozzle:

A jet exhaust produces a net thrust from the energy obtained from combusting fuel which

is added to the inducted air. This hot air passes through a high speed nozzle, apropelling

nozzle, which enormously increases its kinetic energy.

Increasing exhaust velocity increases thrust for a given mass flow, but matching the

exhaust velocity to the air speed provides the best energy efficiency. However, momentum

considerations prevent jet aircraft from maintaining velocity while exceeding their exhaust

jet speed. The engines of supersonic jet aircraft, such as those of fighters and SST aircraft

(e.g. Concorde) almost always achieve the high exhaust speeds necessary for supersonic

flight by using a CD nozzle despite weight and cost penalties; conversely, subsonic jet

engines employ relatively low, subsonic, exhaust velocities and therefore employ simple

convergent nozzle, or even bypass nozzles at even lower speeds.

Rocket motors: maximize thrust and exhaust velocity by using convergent-divergent

nozzles with very large area ratios and therefore extremely high pressure ratios. Mass flow is at a

premium because all the propulsive mass is carried with vehicle, and very high exhaust speeds

are desirable.

Fig.10Propelling nozzle



3.7.6 Shaping nozzle:

Some nozzles are shaped to produce a stream that is of a particular shape. For

example, extrusion molding is a way of producing lengths of metals or plastics or other materials

with a particular cross-section. This nozzle is typically referred to as a die.

Fig.11Shaping nozzle



Table 2: Nozzle size at different pressure

Table 3: Droplet size at different pressure



3.8 Regulator:

The main function of the regulator is to control the flow of water into the nozzle. With

the help of regulator it will increase or decrease the flow of water.

Fig .12Regulator

3.9 Electrical fan:

A fan is a machine used to create flow within a fluid, typically a gas such as air. The fan

consists of a rotating arrangement of vanes or blades which act on the fluid. The rotating

assembly of blades and hub is known as an impeller, a rotor, or a runner. Usually, it is contained

within some form of housing or case. This may direct the airflow or increase safety by

preventing objects from contacting the fan blades. Most fans are powered by electric motors, but

other sources of power may be used, including hydraulic motors and internal combustion

engines. Fans produce flows with high volume and low pressure (although higher than ambient

pressure), as opposed to compressors which produce high pressures at a comparatively low

volume. A fan blade will often rotate when exposed to a fluid stream, and devices that take

advantage of this, such as anemometers and wind turbines, often have designs similar to that of a

fan.

Fig.13 Electric fan



CHAPTER-4

MODEL CALCULATIONS

4.1 Sample calculations:

Given data:-

Power of the motor =15 watts

Diameter at inlet section -1 (D1) =10 mm

Diameter of outlet section -2 (D2) =5mm

Solution:-

Area of section -1 ( A1)=πx(10)²/4=78.53

Area of section -2 (A2) =πx(5)²/4=19.63

Water discharge Q=0.681 lit /min ( 374 w=17 L, 1w=17/374)∵

15w= 17x15/374=0.681L/m

Water discharge (Q)=A1xV1

0.681=78.53xV1

V1=8.67mm/min

Volume of cylindrical tank (V)=πr²h

=78539.81mm³ ans.

Mass (m) =ρxv

=0.001x78539.81

=78.539 gram.

Pressure (p) = w/t = (fxds)/t

P1 = (mxv²)/t

=78.53 x (8.67)²

=5903.01 N/mm²



A1xV1=A2xV2

Volume of pipe (V2) =A1xV1/A2

=78.53x8.67/19.63

=34.68 mm/min

V2²/2g + V1²/2g = p1-p2/ρg (From Bernoulli’s equation)

34.68²/2x2.725 + 8.67²/2x2.725= 5903.01-P2/0.001x2.725

P2=5902.37 (pressure at section -2) Ans.

4.2 Advantages:

Estimated cost for installation is about half that of centralrefrigerated air conditioning.

It reduces the temperature of the surrounding very fast.

Power consumption is limited to the fan and water pump. Because the water vapor is not

recycled.

The only two mechanical parts in most basic misting fan are the fan motor and the water

pump.

Construction of the evaporative cooler is simple.

4.3 Disadvantages:

Misting fan require a continuous supply of water to wet the systems.

The water supply line may need protection against freeze bursting during off-season,

winter temperatures.

In this mechanisms water is supply in the tube so rusting takes place. So after few months

it should be chance.

CHAPTER-6NRCM,Department of Mechanical Engineering25


FUTURE SCOPE AND CONCLUSION

6.1 Future Scope:

In the advance technology the Misting fan is similar to the cooler which is used in

summer season, But it work in both direction in horizontal and vertical direction. It

requires less space and we can fit this fan anywhere such as home, office. We can use this

fan for large space because the cooler is able to cool the environment. In the party we

want to keep the surrounding in good condition clean we can mix perfume into the water

so the people feel good smell.

This system can also use in Athletes events. On the side of the road we can fit the

mist fan so athletes feel cool while they all are running on the road.

6.2 Conclusion:

We conclude that this misting fan cool the surroundings in summer session. Other

fan only gives the air but it does not dry the sweat. But this fan gives the air with cool

fine spray which reduces the temperature of the surrounding because it increases the

humidity of the air.

We also conclude that other fan accept mist fan is not possible to adjust or fitted

at anywhere. But mist fan is fitted at any place such as in office on the corner of the wall

and on the near the road while the athletes run on the road it feels cool.

References:



1. Kheirabadi, Masoud (1991). Iranian cities: formation and development. Austin, TX:

University of Texas Press. p. 36. ISBN 978-0-292-72468-6.

2. Zellweger, John (1906). "Air filter and cooler". U.S. patent 838602.

3. Bryant Essick (1945). "Pad for evaporative coolers". U.S. patent 2391558.

4. Scott Landis (1998). The Workshop Book.Taunton Press. p. 120. ISBN 978-1-56158-

271-6.

5. Gutenberg, Arthur William (1955). The Economics of the Evaporative Cooler

Industry in the Southwestern United States.Stanford University Graduate School of

Business. p. 167.

6. "Jet nozzles, Type DUK" from TROX Company, retrieved 15th October 2013 from

7. GFC Rogers, and Cohen, H. Gas Turbine Theory, p.108 (5th Edition), HIH

Saravanamuttoo.


https://books.google.com/books?id=uq1EAAAAIAAJ

https://books.google.com/books?id=uq1EAAAAIAAJ

https://en.wikipedia.org/wiki/Special:BookSources/978-1-56158-271-6


https://en.wikipedia.org/wiki/International_Standard_Book_Number

https://books.google.com/books?id=bs7I7qf5cUQC&pg=PA120&dq=evaporative+cooler+%22squirrel+cage%22+southwest+popular

http://www.google.com/patents?id=Z2BKAAAAEBAJ&pg=PA1&dq=excelsior+evaporative-cooler&as_drrb_is=b&as_minm_is=1&as_miny_is=1900&as_maxm_is=1&as_maxy_is=1950&num=30&rview=1&source=gbs_selected_pages&cad=0_1#PPA1,M1

http://www.google.com/patents?=04pHAAAAEBAJ&printsec=abstract&zoom=4&dq=cooling+excelsior&as_drrb_is=b&as_minm_is=1&as_miny_is=1799&as_maxm_is=1&as_maxy_is=1910&num=30#PPA2,M1


https://en.wikipedia.org/wiki/International_Standard_Book_Number