Experimental Study On Heat Enhancement Of Gravity Heat Pipe With Single-line Internal Helical Microfin

Heat pipe as an efficient heat transfer components,has been widely used in engineering applications,scientific research,energy development and other fields.In recent years,with the country’s attention to the issue of energy consumption,enhancing heat transfer performance of heat pipe technology to become an important part of the study.In this paper,by referring to the references,understanding the research status of heat pipe heat exchangers at home and abroad,this research divides them into three categories as different heat source supply ways,dealing with the inner wall of the shell and improving the inner components and working fluid.In order to investigate the effect of heat treatment on the inner wall of the shell,by the way to arrange single-line internal helical microfin,this research designed the gravity heat pipes with different internal helical microfin distributions and the smooth gravity heat pipe.By analyzing the heat transfer model of gravity heat pipe and the basic theory,the relative heat transfer limit is calculated.The heat transfer process of heat pipe and the heat transfer enhancement mechanism of internal helical microfin structure are discussed.In this research,the experiment system is set up,the experimental data processing method is given,and the error analysis is carried out.The comparison of the heat transfer characteristics between the smooth gravity heat pipe and the gravity heat pipe with internal helical microfin shows that the starting performance of the gravity heat pipe with internal helical microfin is better than that of the smooth gravity heat pipe.Under different heating conditions,the internal helical microfin structure makes the heat transfer of the gravity heat pipe be strengthened,the transmission power is increased,the equivalent convective heat transfer coefficient is increased,and the total thermal resistance is reduced.When the two kinds of gravity heat pipes are placed in the small inclination angle,the effect of improving the equivalent convective heat transfer coefficient is not as good as the big inclination angle.When the oil bath temperature is 150 ℃,the best inclination angle is 75°.The effect of single-line internal helical microfin distributions on the heat transfer enhancement of the heat pipes is studied.It is found that the starting characteristics of the gravity heat pipes with different single-line internal helical microfin distributions are better than the smooth gravity heat pipe at the same oil bath temperature.And the gravity heat pipe with all single-line internal helical microfin has the best effect.At the different oil bath temperature,the arrangement of internal helical microfin can effectively reduce the heat pipe operating temperature.The calculation results of convective heat transfer coefficient show that,the experimental selection of internal helical microfin arrangement in the adiabatic section and the condensation section has the best effect on heat transfer enhancement.In the experiment,the effect of heat transfer enhancement about internal helical microfin arrangement in the adiabatic section is not good.According to the analysis of two aspects on the internal helical microfin strengthening factor and the filling rate,it is concluded that the main influencing factor is the filling rate.