Heat Transfer Analysis of Flat Heat Pipe With Enhanced Microchannel Shape

Abstract

Flat heat pipe has many excellent characteristics such as high thermal conductivity, reversibility of heat flow direction and so on. In this paper, a flat heat pipe model with multiple microchannels is established, and the effects of different microchannel shapes and different materials on the heat transfer efficiency of flat heat pipe are studied. Then, based on the general rectangular and inverted trapezoidal microchannel shape, the enhancement is carried out. That is to fill a number of materials in the bottom of the microchannel to change the bottom shape of the microchannel. In the steady-state thermal simulation of flat heat pipe, the axial temperature of the flat heat pipe with enhanced microchannel shape is lower than that of the flat heat pipe with general microchannel, which shows that the enhanced microchannel shape is helpful to the heat dissipation of flat heat pipe. The fluid simulation results show that the enhanced rectangular microchannel shape can accelerate the current velocity of working fluid. Therefore, the flat heat pipe with enhanced microchannel shape has better heat transfer performance. In order to obtain the local temperature of flat heat pipe quickly, the transient analytical solution is provided. In this paper, the temperature field calculated by using transient analytical solution is compared with that simulated by COMSOL. The results show that the maximum error between the results of discrete heat source model and continuous heat source model calculated by transient solution and COMSOL simulation results is less than 2%.INDEX TERMS Flat heat pipe, microchannel shape, heat dissipation, analytical solution.

Simulation and Experimental Study on Vacuum Negative Pressure Infusion of Working Fluid for Micro Heat Pipes

“…For example, due to the low thermal resistance and high capillary force of flat plate heat pipe (FPHP), the highest temperature of FPHP integrated with a 120W LED module could be decreased by 28%, as compared to a commercial substrate [3]. Especially, micro heat pipe (MHP) which differs from a conventional heat pipe has been attracting more and more attention, because it does not contain a wick instead of the sharp edges of microgrooves or is in form of a single closed serpentine tube to circulate the working fluid [7], [8]. A novel skew-grooved structure was proposed for MHPs to improve the capillary force of the grooved wick and then promote the return of the condensate to the evaporator [9].…”