Heat Transfer Performance Study Of The Flat Heat Pipe

Recently,with the development of Electronic Science and Technology,The trend of electronic components to put toward the high-frequency, high-speed integrated and modular, and the consequences of this trend is caused by the thermal control of electronic components hinder technological development has become more and more difficult.Efficient cooling device is essential for the progress of the electronics industry to continues.Micro flat heat pipe is a vacuum with working fluid, which can transfer of heat from the heat source to the heat sink by the phase transition(evaporation and condensation of liquid),Therefore,it has small scale,strong heat transfer capacity,good thermal control, good thermal gradient and and low environmental requirements.It’s very popular in the thermal design of electronic equipment.In this paper,we design and produce a micro flat heat pipe with rectangular channel in it,and then do some numerical simulation about phase transition and the temperature gradient,at last we have some experimental tests about the main factors affecting the heat transfer performance.The main contents are as follows:First,some basic research for the flat heat pipe, heat transfer and thermal design had been done.After the research of flat heat pipe heat transfer limit,calculate and get the capillary limit is the main parameter to limit flat heat transfer performance.Then, using numerical simulation software Fluent for flat heat pipe phase transition.By analyzing the simulation results found that the number of bubbles, bubble temperature and velocity is affected by the positions of heat source.When the heat source is placed in the middle of the plate heat pipe,we can get the best result.Calculated the surface temperature distribution of both thermal diffusion,flat heat pipe compared to pure aluminum heat spreader for better heat transfer capability and temperature gradient.Next, calculate the parameters and materials of the micro flat heat pipe.Following the design, after machining, cleaning, welding and leak detection, vacuum and liquid injection processes,we successful get the test piece with deionized water as the working fluid.Finally,through the performance experimental of the flat heat pipe,the result shows:flat heat pipe has the best performance when the power of heat source is 60 W ~ 90 W,Meanwhile, the test piece with rectangular channel channels performances better than vacuum chamber without channels,small changes in the rate of filling can also cause a great impact on the performance of a flat heat pipe,In this experiment, the best filling rate is 30%,heat source is placed in the best location in the middle of the plate heat pipe, in which case the minimum diffusion resistance, the best performance.