Theoretical Analysis And Experimental Study Of Thermal Ground Plate

The heat transfer performance of Thermal Ground Plate (TGP), which is based on the heat transfer of phase change of liquid in micro-channels, is investigated experimentally and theoretically in this paper. The main contents are stated as following:Firstly, the micro-channel structural TGP is designed. The outside dimensions of TGP are 100mm×30mm×7mm (Length×WidthxHeight). The inside vapor channels dimensions are 90 mm×20 mm x2 mm. Forty six micro-channels with dimensions of 90mm×0.2mm×0.6mm (LengthxWidthxDepth) are machined as the passages of liquid flow.Secondly, a set of experimental system for the heat transfer of TGP is build up, which includes thermal ground plate, orientation regulator, electrical heater, cooling water circulator, thermal couples, data acquisition system and so on. The heat transfer experiments of TGP in different tilt angles, different liquid charging and evaporation pressure are carried out.Then, based on the theory of classic heat pipe and the characteristics of TGP, the equations are generalized and amended to make it suitable for theoretical calculation of flat heat pipe. The heat transfer performance of TGP is calculated and analyzed by the modified equations. According to the dimensions of TGP and the transfer of vapor-liquid in channels, the operational parameters of TGP are worked out by the calculation of resistance of vapor, resistance of liquid, gravity force and the capillary force.Lastly, the following points are concluded according to the experimental results, (a) As the increasing heat flux, the wall temperature of TGP, the temperature difference, equivalent thermal conductivity and the ratio of thermal conductivity to density all increase. (b) With the increasing of heat flux under the different evaporative pressure, the ratio of wall temperature and temperature difference of TGP charged with 1 ml alcohol increase, but the equivalent thermal conductivity ratio decreases. (c) Under the optimized operation condition, the maximum wall temperature of thermal ground plate is 40.87℃, the working temperature difference is 17.92℃, equivalent thermal conductivity is 1150W/(m·K), the ratio of thermal conductivities is 3.86 and the ratio of thermal conductivity and density is 4.91.