Numerical Investigation of the Effect of Pulses on the Performance of Axially Rotating Heat Pipe

This paper numerically simulated a heat pipe to investigate the effect of combined rotation and pulse on the performance of rotating heat pipes (RHPs) where transverse or longitudinal pulses may occur during abnormal operations. A three-dimensional numerical model of the axial rotating heat pipe was developed. The investigation includes analyzing one pulse and continuous pulses to reveal their effect on the heat pipe performance. Specifically, the time needed for the heat pipe to stabilize for the single or continuous pulse signal. In addition, the effects of the continuous pulse amplitude and frequency on the heat pipe performance are explored. The simulation results showed that single and continuous transverse pulses at 0.1 Hz applied in the X and Y directions do not affect RHP performance compared to the rotation-only case. However, the single longitudinal pulse in the Z-direction improved the RHP performance by 7.1%. The effective thermal conductivity of rotating heat pipes at 10 Hz is higher than that at 0.1 and 1 Hz by 190.4% and 199.1% during pulses and lower by 14.4% and 5.7% after pulses, respectively. At a pulse amplitude of 2mm, the effective thermal conductivity is higher than at 1 and 4mm amplitudes by 12.6% and 25.0%, respectively. Thus, the best RHP performance is at 2mm amplitude and deteriorates as the pulse amplitude increases or decreases.