Performance Comparison of Fluids in a Closed Loop Pulsating Heat Pipe

Abstract

The pulsating heat pipe is the advent of avid progression for the rise of heat transfer technology, which in a plethora of modern techniques has risen automatically to the forefront of microelectronics cooling. Recent advances in electronics design and manufacturing resulted in significant increases in heat flux density through miniaturization of components and a simultaneous increase in power requirements associated with increased product functionality. As a result, production of microelectronics cooling devices will be of optimal importance in the face of scientific development. A PHP or pulsating heat pipe is essentially a non-equilibrium heat transfer device whose performance success depends on continuous maintenance of nonequilibrium conditions within the system. A pulsating heat pipe also promises alternatives for the removal of high localized heat fluxes to provide necessary level of temperature uniformity across the components that need to be cooled. The heat is thus transferred not only by latent heat transfer like in other types of heat pipe, but also by the sweeping of the hot walls by colder moving fluid and vice versa. This phenomenon is the reason of high efficiency of PHPs in comparison with other heat pipes. The aim of this research paper is to better understand the operation of PHP through experimental investigation and obtain comparative results with better for different parameters. A series of experiments are conducted on a closed loop PHP with 8 loops of copper capillary tube of 2mm internal diameter. Initially only ethanol was taking as working fluid, later a blend of ethanol and methanol are used as working fluid and the corresponding effects on the process parameters are measured. The operating conditions are the heat input, filling ratio. For both the working fluid, the filling ratios were taken separately, measure of them being 50%,60%,70%,80%. This paper, shall primarily demonstrate the effect of different parameters on the closed looped system and from where the effects of this parameters on the basic heat transfer properties changes in tis value of the content which is the required or specific target of the experiment. Important insights of the operational of CLPHP are obtained and optimum performance and its variation with different working fluid is identified and studied. To conclude, PHP or CLPHP will remain one of the foremost technology for heat transfer at low weight and cost.