Flow and heat transfer characterization of liquid-vapour osculating flow in pulsating heat pipe working with base fluid's

This is my new project work

Abstract:-
1.Pulsating heat pipe can be an efficient solution for thermal management of micro electronics's system.
2.These device are simply to be constructed and can be utilized effectively for different practical application.
3.In the present work,experimental investigation would be carried out and the pulsating motion in pulsating heat pipe will be analyzed.

Introduction:-
1.It is a simple device and used to the transfer from heat one place another place ie;evaporator to condenser.
2.It was 1st proposed Akachi as a passive cooling device.
3.Pulsating heat pipe (php) are one of latest developments in the area of the heat transfer.
3.Pulsating heat pipe can have extremely high thermal conductivity in steady state operation.

LITERATURE SURVEY:-
1.Piyanum charoesawan metal:-
                                                          Using the copper tubes comprising 1mm internal diameter and 2mm outer diameter were used in fabrication of closed loop in pulsating heat pipe.
#  They observed that the flow of characteristics such as slug velocity, the overall pressure drop in Php had impact of the selection of working fluid.
#  They noticed that the bubble nucleation, their shape,growth,collapse and bubble pushing action were affected the selection of working fluid.

2.Khandekar metal:- Presented an experimental study on a close loop PHP made of copper tubes 5 turns and 2,3mm inner and outer diameters
# They experiments were performed with the varying fill ratio 0-100% using water and ethanol as working with fluid.
# He was identified that 0% fill ratio indicates bare PHP without the working fluid inside of it.
The heat transfer through the PHP was due to pure conduction processing higher thermal resistance.
# At 100% fill ratio no pulsation of the working fluid.
# True PHP only in the fill ratio of range 20%-80%.

3Qingjuncai etal;-
                              studied the effect of heat input on the performance of php.
#  The experimental findings showed that the temperature difference across the evaporator and condenser increases with the increase in the the heat input.

OBJECTIVE;-

• This project attempts to describe the effect of working fluid,heat input,fill ration as primary design parameters on the performance of php.
• The transient and steady state experiments are connected for various heat loads,working fluid,fill ratio.
• Here we find out the heat transfer coefficient and thermal resistance and we compare the different base fluid heat transfer performance.

WORKING PRINCIPLE;-

• Php works on the principle of fluid pressure oscillation that are the created by means of differential pressure across vapour plugs from evaporator to condenser and back.
• The vapour formed at the evaporator is pushed towards the condenser.
•   the vapour gets condensed at the condenser releasing the latent heat of vaporization and returns to the evaporator to complete cycle.
• The thermal performance of an actual PHP depends upon the thermal gradient exist between the evaporator and the condenser section.

PARTS REQUIRED;-

1. U-shape brass tube
2. Boro silicate rubber tube
3. silicon rubber tube
4. temperature data logger 
5. wire heater 
6. syringe
7. thermo couple
8. glass wool

EXPERIMENTAL PROCEDURE ;-

• Before filling the fluid in the php it is ensured that no traces of working fluid used in previous cycle of experimentation  is available.
• The required amount of working fluid is then filled using a syringe by opening the one end valve such that fluid directly enters the evaporator section.
• Now the air is filled through the filing valve provided on the brass tube using another syringe.This is done to ensure simultaneous formation of liquid slug and vapour bubble.
• The display unit is ON and required voltage is set using the power supply unit in the present experimentation.
• The cooling water is allowed to pass the condenser section of PHP for condensing vapour.
• The transient experiments are conducted and the temp at various locations of the php are recorded from the temp data logger.

APPLICATIONS ;-    

 

Result ;-

CONCLUSION ;-

• 70% fill ratio is found to be the optimum for php operation giving heat trasfer more in the form of sensible heat.
• Due to absence of gravity in horizantal mode of operation ,the pressure pulsating caused due to the temp difference are enough to push the liquid slugs and vapour bubble.
• As the movement of the fliud is very slow at lower heat input the temp difference increases at low heat input.
• Increase in heat input decrease the thermal resistance and better transfer rates are observed .
• It is provide from the couple of experiments conducted that acetone exhibits superior heat transport capability compared to any other fluids with lesser temp difference of 19 0c between the evaporator and condenser.
• The flow visualization studies revealed the existence of slugs flow at lower heat inpunt annular flow at higher heat inputs in a PHP.
• At a heat inputs in php  
• At a heat input of 10w ,the heat transfer coefficient and thermal resistance obtained for acetone was 990w/m2k and 1.02k/w respectively.