Heat Pipe Final2..

8/10/2019 Heat Pipe Final2..

1/16

1

Rajesh v pati l rode

Mechanical dept.

D .Y . Patil college of engg. & tech

Guided By:

Prof. R.G. Benni


2/16

Heat pipe is a simple device that can

quickly transfer heat f rom one point to

another. They are often referred to as

the " superconductors" of heat as theypossess an extra ordinary heat transfer

capacity & rate with almost no heat

loss. I t is a device of high thermal

conductance

2


3/16

Very high effective thermal conductance

An isothermal sur face of low thermal impedance

Abil i ty to act as a thermal f lux transformer

3


4/16

Idea of heat pipes was first suggested by R.S.Gauglerin 1942.Grover was interested in development of hightemperature heat pipes, employing liquid metalworking fluids, & suitable for supplying heat to

emitters of thermionic electrical generators & ofremoving heat from collectors of this device. Shortlyafter Grovers publication, work was started on liquidmetal heat pipes by Dunn & Neu. At the same timeCotter published paper on heat pipe giving betterunderstanding of heat pipe theory. Then its

remarkable properties were appreciated & seriousdevelopment was begun

4


5/16

The three basic components of a heat pipe are:

working fluid

wick or capillary structure

container

5


6/16

The prime requirements are compatibility with wick and wall materials wettability of wick and wall materials acceptable freezing or pour point low liquid and vapor viscosities good thermal stability vapor pressure not too high or low over the operating

temperature range high latent heat

high thermal conductivity

6


7/16

The prime purpose of wick is to generate capillarypressure to transport working fluid from the condenser

to evaporator. It must also be able to distribute liquidaround evaporator section to any areas where heat islikely to be received by heat pipe. Other necessaryproperties of the wick are compatibility and wettability.

7


8/16

Selection of the container material depends on following factors: Compatibility (both with working fluid and external

environment)

Strength to weight ratio

Thermal conductivity Ease of fabrication, including welding, machineability and

ductility

Porosity

Wettability

8


9/169


10/16

Heat pipe is activated by temperature difference and therefore

no consumption of energy.

Because there are no moving parts, there is no maintenance

and nothing to break.

Very high effective thermal conductance

They possess an extra ordinary heat transfer capacity & rate

with almost no heat loss

10


11/16

Length of heat pipe is limited.

Design is complicated.

Undesired increase in point-to-point temp. differentialalong the heat pipe can to damage to evaporator

section.

11


12/16

Space Technology

Spacecraft temperature equalization

Component cooling, temperature control and radiator design

in satellites.

Other applications include moderator cooling, removal of heat

from the reactor at emitter temperature and elimination of

troublesome thermal gradients along the emitter and collector

in spacecrafts

12


13/1613


14/16

The use of heat pipes has been mainly limited to spaceapplication until recently, due to cost effectiveness andcomplex wick construction of heat pipes., Laptops, airconditioner, PCB, dehumidifier and many more other fieldswhere heat pipes can be applied more effectively. More &

more research is going on to overcome the limitations of heatpipe. In future we will see heat pipes to be used for heattransfer instead of other conventional heat transfer devices. In

future heat pipe will create its own position in every field ofscience.

14


15/16

Books

Heat & Mass TransferS.C.Arora

Heat TransferPavaskar

Websites

www.google.com

www.heat pipe.com

www.wikipedia.com

15
http://www.google.com/http://www.google.com/


16/16

THANK YOU

16

Heat Pipe Final2..

Documents

Transcript of Heat Pipe Final2..