Design And Thermal Analysis Of Double-Sided Plate Heat Pipes With Micro-Rectangular Channels

At present,micro-rectangular channel plate heat pipe becomes the focus of research and development. It’s using the principle of phase change heat transfer and having high thermal conductivity. So the heat of internal high flux electronic equipment can be quickly taken away to avoid partial overheating problem. Nowadays, there are many studies about this technology,but the results remain to be turned over because it lacks available system to verification. At the same time, it lacks the influence factor analysis of start-up performance and heat transfer performance. In this paper, design and thermal analysis of a double-side micro-rectangular channel plate heat pipe has been operated. And it lays the foundation for its application on electronic equipment.(1)This paper introduces the design methods and manufacturing processes of plate heat pipe. And the main limitation of heat transfer performance of plate heat pipe is Capillary limitation through checking.(2) The flow in micro-plate heat pipe has a stronger size effect because its channel is small. The result has a huge bias between the finite element analysis software and experiment. So the mode of a plate heat pipe has been established based on the theory of evaporating thin film. And it solved by fourth step Runge-Kutta algorithm. the axial and radial distribution of gas and liquid in micro channel, thickness of evaporating thin film, distribution of heat flux and temperature have been got. These have a good agreement with experiment.(3) Through testing the thermal performance of double-side micro-rectangular channel plate heat pipe. It is found that the thermal performance is better if the heat pipe is horizontal instead of vertical, while its start-up performance is terrible. The mainly reason is that the thermal performance has been enhanced by the gravity accelerates the flow of liquid in the heat pipe when it’s vertically. Meanwhile, the gravity will accelerates the accumulation of liquid in the heat pipe at the end of evaporation to affect the start-up performance of the heat pipe. So the heat pipe cannot be started under a small heat transfer. It starts must be in a large heat transfer and a high hot end temperature. In this process, the temperature is jumping between hot and cold side. The temperature of the hot end is decreased rapidly and the cold end increases rapidly. The heat pipe can be started quickly without temperature jump between the hot and cold side when its horizontally.(4) The influence factors of thermal performance and start-up performance of the micro-plate heat pipe has been analyzed. The result shows that the filling ratio, angle of slope, heating power, heating position, vibration and the initial distribution of the liquid have a larger influence to the thermal performance.