Research On Heat Transfer Performance Of Flat Micro Heat Pipe

The amount of heat generated by a chip in an electronic product per unit area is increasing,and thermal management has become a very attractive research direction in the electronic product industry.Either the local high temperature of the electronic device or the high temperature of the electronic device as a whole can affect the workability of the electronic product and bring about a large thermal stress.Therefore,it is very important to effectively reduce the temperature of electronic devices in a narrow space.Therefore,we need thinner and more efficient cooling devices.The micro heat pipe is one of the most promising solutions for heat dissipation of electronic products,especially in high power electronic devices such as LED lighting or portable game PCs.As an efficient heat-conducting device,micro-plate heat pipe has more advantageous in the thermal control system of a compact device with limited space,but there is still room for improvement in performance.In this paper,silicon is used as the substrate material of the micro flat heat pipe,Pyrex 7740 glass is used as the glass cover plate,the silicon substrate of the micro heat pipe is aligned with the glass cover plate,the finished product heat pipe is electrostatically bonded.The micro heat pipe infusion system is set up to adopt peristaltic motion and the pump performs micro-infusion of the micro heat pipe.A pulsating micro-heat pipe and a micro-heat pipe without a steam chamber structure are designed and manufactured.The steam chamber structure connects the top space of the micro-heat pipe,increases the circulation space of the steam,and reduces the shearing force and the friction force in the process of circulating the working fluid.the heat transfer capability improved.The test platform was used to test the heat transfer performance of the finished heat transfer device.20°C circulating cooling water equipment used as cooling device and The micro flat heat pipe was tested in a vacuum environment.Test results for the pulsating heat pipe,when the input power is 1 to 6 W,the temperature when the micro pulsating-heat pipe with the horizontal direction channel reaches the equilibrium state is 33.6° C.,49.6° C.,67.2° C.,83.1° C.,101° C.,117 respectively.°C;The temperature of the pulsating micro-heat pipe with the lateral direction channel reaches the equilibrium state is 31°C,46.4°C,63.4°C,81.7°C,95.6°C,111.8°C,respectively.A 20% ethanol solution will increase the heat transfer efficiency of the horizontal pulsating heat pipe.At the same power,the equilibrium temperature of the heat pipe with the steam chamber is lower than the equilibrium temperature of the heat pipe without the steam chamber.With the increasing of the power,the temperature difference between the micro-heat pipe with the steam chamber and the micro heat pipe without steam chamber is also increasing,indicating that the micro-heat pipe in the steam chamber has better application effect under higher power.The theoretical analysis of the effect of W-channel,triangular channel and rectangular channel on the capillary force is performed.The theoretical analysis shows that the capillary force of the channel structure with the channel?s width of 150 ?m and the channel wall?s width of 100 ?m is larger than the capillary force with the channel?s width of 175 ?m and the channel wall?s width of 75 ?m.The capillary force with the channel?s width of 175 ?m and the channel wall?s width of 75 ?m.is larger than the capillary force with the channel?s width of 200 ?m and the channel wall?s width of 50 ?m,and the simulation analysis of deionized water flowing in the W channel is performed.The simulation analysis results are in accordance with the theoretical analysis results.And designed a mask of W-channel structure.Through the above-mentioned theoretical and experimental research,the micro plate heat pipe has excellent performance,and the specification parameters of the heat pipe are modified according to the limitations of actual working conditions,and can meet the heat dissipation requirements of more electronic products.