The effect of substrate conduction on the thermal performance of a flat plate pulsating heat pipe

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Pulsating Heat Pipes (PHPs) are proposed as one of promising cooling techniques of high heat flux devices. PHPs can be classified into two groups, tubular PHPs made from a capillary tube bent into many turns and Flat-Plate PHPs (FP-PHPs) which have channels engraved on a base plate. The biggest difference between two PHPs is the heat conduction through the solid wall of FP-PHP, while the conduction effect in tubular PHPs is negligible. Therefore, there are two main heat transfer paths in FP-PHPs, axial conduction through the solid wall and heat transfer by rapid self-sustained oscillation of working fluid. However, there also exists transverse conduction between neighboring channels through thin channel wall. The transverse conduction influences on the heat transfer by working fluid, since it reduces the thermally created oscillating motion of working fluid. By restricting the transverse conduction, the thermal performance of FP-PHPs was enhanced by more than 30% due to larger amplitude oscillation of working fluid. Moreover, early start-up and smaller fluctuation in evaporator temperature were obtained by confining the transverse conduction.