An experimental comparison of thermal performance: Smooth and inner-grooved closed loop pulsating heat pipes in different angles

Abstract

Abstract Pulsating Heat Pipes are ideal for compact cooling applications such as electronic cooling. In this experimental research, the thermal performance of Inner-Grooved Pulsating Heat Pipes (IGPHP) and Smooth Pulsating Heat Pipes (SPHP) compared using distilled water in different angles. The inclination angles of 0o, 5 o, 15 o, 30 o, 50 o, 70 o, and 90 o, and the input heat range of 50-300\xa0W were studied. The results show that the optimum filling ratio is 60% for IGPHP and SPHP. The study shows that in constant Input heat, the thermal resistance of IGPHP is lower than SPHP and the effective thermal conductivity of IGPHP is higher compared to SPHP. The average reduction of the thermal resistance of IGPHP compared to SPHP was found 21% across all angles and input heat powers; however, the average reduction was 49% for the angle of 5 o across all input heat powers. The dryout phenomenon for IGPHP took place at 0o and the input heat of 100\xa0W, while for SPHP, this occurred at 5o and 250\xa0W. The overall comparison shows that IGPHP is an even better alternative to SPHP in higher capacity applications.