Heat Transfer Characteristics of Taper Radially Rotating Heat Pipe Using R-11 as Working Fluid

Abstract

This research was to study the effects of inner taper, inclination angles, rotational acceleration and aspect ratios on heat transfer performance of a taper radially rotating heat pipe. The tested heat pipe was made of copper tube with an outside diameter of 25.4 millimeters. The aspect ratios were 2, 4 and 6 respectively. The inner taper heat pipes were 0.5, 1, 1.5 and 2 degrees respectively. The inclination angles were 0 and 90 degrees. The rotational acceleration was 3g, 7g, 10g and 20g (g=9.81 m/s 2 ). R-11 was used as the working fluid with a filling ratio of 60 percent of the volume of the evaporator section, and the evaporator was heated using a heater. The adiabatic section was well insulated to protect heat loss in which heat is released to the ambient air by natural convection. From the experimental results, it could be concluded that, when the inner taper heat pipe was increased from 0.5 to 2 degrees, the heat transfer rate also slightly increased. This seemed to be the trend of all the inner taper heat pipes. When the aspect ratio was increased from 2 to 6, the heat transfer rate slightly decreased. The inclination angle of 0 degrees gave a greater heat transfer rate than an inclination of 90 degrees. When the rotational acceleration was increased from 3g to 20g, the heat transfer rate also slightly increased. This seemed to be the trend of all the inner taper heat pipes as well. In conclusion, when the inner taper was 2 degrees with an aspect ratio of 2 and an inclination angle of 0 degrees, it was found that the maximum heat transfer rate was 20,163.6 watts per square meter .