Depriming/rewetting of arterial heat pipes - Comparison with Share-II flight experiment

Abstract

Utilizing several previously developed analytical expressions, a combined analytical and numerical model was developed to analyze the deprime and reprime/rewetting characteristic s of two high-capacity external artery heat pipe designs undergoing externally induced accelerations. The analysis considered three distinct phases of the deprime and reprime/rewetting process: 1) the effect of longitudinal accelerations on the depriming, 2) the time required for reprinting of the liquid artery once the longitudinal acceleration had been terminated, and 3) the rewetting characteristics of the circumferential wall grooves. Combining these three processes, a technique was developed by which the effect of external accelerations on the operational characteristics of the external artery heat pipes could be predicted. The results of this analysis were then compared with the experimental results obtained from acceleration tests on these two heat pipe configurations conducted aboard STS-43 in August 1991. The depriming analysis indicated the importance of frictional effects on the liquid configuration during an external acceleration. In addition, the evaporator recovery time of the heat pipe was found to be dominated by the liquid artery reprime/rewetting characteristic s as opposed to the characteristics of the circumferential wall grooves. Overall, this technique compared favorably with the microgravity flight results and confirmed the accuracy of the analytical techniques.