【書報討論 2022/11/17】《第十週》 場次二
講者：國立陽明交通大學機械工程研究所 孫建宏博士生
講題：Investigation of centrifugal force on maximum heat transfer of the heat pipe
時間：2022/11/17 (周四) 3:30 pm - 5:30 pm
地點：工程五館 B1 國際會議廳

摘要：
In this study, experiments were conducted to examine the effect of rotation (centrifugal force) and inclination angle on the performance of a 6.0 mm diameter heat pipe. Experimental tests were carried out under static a nd dynamic conditions, respectively. The tube wall of the heat pipe is made of pure copper material, the internal capillary structure is made of sintered copper powder, and the working fluid is deionized water. The static test ranges from 1.0g to 1.0g, an d the thermal resistance value and maximum heat transfer of the test heat pipe are affected by the inclination angle. Dynamic tests range from 1.75g to 1.75g. The g force is provided by the centrifugal force generated by the rotating platform. For static testing, the inclination angle has little effect on the thermal resistance value of the heat pipe, provided that dry out does not occur. The main effect of the inclination angle on the performance of the heat pipe is the maximum heat transfer before dry ou t. With the change of the inclination angle of the heat pipe, it is found that the maximum power of the heat source evaporator placed at the bottom is about five times that of the heat source positioned at the top. Additional centrifugal force was introduc ed during the dynamic test rotation, which may play an important role in changing the maximum heat transfer capacity of the heat pipe. The test results show that when the centrifugal force is lower than 0.38g, there is no significant difference in the maxi mum heat transfer between the static and dynamic tests. With further increases in centrifugal force, the data for both tests began to increase in deviation. Under the tested gravity condition of 1g, the maximum heat transfer rate of the dynamic test exceed s 70.1% of that of the static test. For the heat pipe operating under static conditions, the existing theoretical prediction formula can reasonably predict the maximum heat transfer amount of the heat pipe under different inclination angles. However, the e xisting theoretical prediction formulas cannot provide good prediction values when the g of the dynamic test exceeds 0.38 g. During the analysis, it is found that the flow velocity of the working fluid inside the heat pipe in the capillary structure is low , which is not in the linear state of Darcy flow, but in the nonlinear state of Darcy flow in the past. By considering the second order effect of Darcy's equation, the theoretical prediction formula, combined with the accurate measurement of the permeabili ty value of the former Darcy flow state and the correction of the evapotranspiration rate, the result of predicting the maximum power in the dynamic test can be more accurate