An Oscillating Heat Pipe with Check Valves (CVOHP) is a two-phase thermal control device that is thin thickness, lightweight and has a large heat-receiving surface. In addition, a CVOHP has high heat transfer performance because it transfers heat using latent heat and sensible heat. Therefore, a CVOHP is attracting attention as a novel thermal control device for spacecraft. This study aims to clarify the optimal number and orientation of check valves to maximize the heat transfer performance of the CVOHP. The experiments were conducted using four types of 15-turn CVOHP with different numbers of check valves: every turn, every two turns, every five turns, and no check valves. The effect of the orientation of the check valves was also investigated in two cases. One was a case where the check valves allowed flow from the cooling section to the heating section (forward orientation), and the other was the opposite (backward orientation). The result showed that in the forward case, the thermal resistance decreased as the number of check valves increased. On the other hand, in the case of the backward case, the thermal resistance increased as the number of check valves increased, and the maximum heat transfer capability deteriorated significantly compared to the forward orientation. Based on the results of this study, it is recommended to install check valves at each turn in the forward orientation to maximize the heat transfer performance.
Kawaguchi et al. (2024) studied this question.