Closed Loop Pulsating Heat Pipe: Heat Transfer Characteristics of a Closed Loop Pulsating Heat Pipe with Fin and Wire Insert

Pulsating heat pipes (PHP) have created a newer arena and promising possibilities as passive devices for heat transfer applications, especially suited for thermal management of electronics. A closed loop pulsating heat pipe (CLPHP) made of copper with 2.5 mm ID and 3 mm OD with fin in the condenser section is used in the present work to evaluate the heat transfer performances where the evaporation section is 50 mm, adiabatic section is 120 mm and condensation section is 80 mm. The attempt is to analyze and compare the effects on the heat transfer performances of CLPHP with finned, fin-inserted and un-finned condenser section with inclination angle of 0⁰ (vertical), 30⁰ and 45⁰. Methanol and Ethanol are used as working fluids with 50% filling ratio in CLPHP with 8 loops during the experimentation. The experimental results indicate a strong influence of gravity and thermo physical properties of the working fluid on the performance of the CLPHP studied with different orientation and heat load. The results demonstrate the effect of fin and fin-insert used in condenser section, the input heat flux, inclination angle orientation and physio-chemical properties of the working fluid.