Enhancing the Experimental Performance of Axially Rotating Wickless Heat Pipe Using Annular- and Longitudinally Finned Condensers

This paper investigates the impact of longitudinal- and annular-finned condensers on the steady-state thermal performance of a horizontally rotating wickless heat pipe. The parameters investigated include two fin types (longitudinal and annular) for different numbers of longitudinal (6, 12, and 18) and annular fins (15, 30, and 45) at a constant rotating speed of 1500 rpm and heat fluxes from 2090 to 16,700 W/m². A heat pipe was designed, constructed, and commissioned with seven condenser sections. The heat pipe is charged with water as a working fluid, filling 35% of the internal pipe volume. The results indicated that fins significantly enhance the performance of the rotating heat pipe. The longitudinally finned condenser with 18 fins achieved the highest performance among the condenser configurations. Specifically, at a heat flux of 2090 W/m², the temperature difference between the condenser and evaporator decreased by 71.2% compared to the plain condenser. Additionally, the effective thermal conductivity of the heat pipe exhibits a remarkable enhancement of 3.47 times over the plain heat pipe at the same heat flux. This enhancement highlights a substantial effect of the longitudinally finned condenser on the axially rotating heat pipe performance.