Synergy investigations for the thermal transportation performance of a coaxial gravity heat pipe with internally finned in evaporator section

Abstract

Heat pipe has great potential in the field of building and industrial energy exploitation due to high-efficiency heat transfer capability. In order to enhance the thermo-hydrodynamic performance of a coaxial gravity heat pipe (CGHP), the thermal transport behaviors of CGHP have been fully analyzed. In present research, firstly, the theoretical model and experiment tests of the internal flow and heat transfer of a CGHP is established when it is in a thermo-hydraulically stable operation mode. Subsequently, a coaxial gravity heat pipe was fully investigated to test its effects of thermal transport performance, including input powers, flow velocity, and the number of fins. The results show that mean reductions of overall thermal resistance achieved about 4.93% and 13.43% for fins nf = 4 and nf = 12, respectively. Moreover, the influence of internal fins of evaporator section on the liquid-vapor flow has been comprehensively obtained, including the steam disturbance, generation of bubbles and nucleate boiling. The CFD results reveal that the down fins number ndf = 0 causes bubbles to adhere to the evaporator surface, thereby reducing the heat transfer capability, whereas a ndf = 3 case causes bubbles to easily depart the evaporator surface, enhancing heat transfer capability. Current theoretical and CFD results agreed well with experimental data within mean error being no more than 10%.