Steady-Periodic Acceleration Effects on the Performance of a Loop Heat Pipe

Abstract

The objective of this research is to experimentally investigate the transient operating characteristics of a titanium-water loop heat pipe subjected to a combined steady-state evaporator input heat rate and a steady-periodic acceleration field. For this experimental investigation, a steady-periodic acceleration field, in the form of a sine wave, was generated using a centrifuge table. Radial acceleration peak-to-peak values and frequency of the sine wave were defined prior to conducting each experimental run and ranged from and , respectively. Evaporator input heat rate and condenser cold plate coolant temperature were varied, and , respectively. In some cases, acceleration driven forces complimented the thermodynamic forces, improving loop heat pipe dynamical performance. However, the converse was also true in that transient acceleration driven forces also appeared to counter thermodynamic forces or excite natural frequencies of the loop heat pipe. This resulted in immediate failure of the loop heat pipe to operate, delayed failure, or in some cases, the loop heat pipe operated in a stable manner but in a degraded condition.