Constrained Vapor Bubble Experiment for International Space Station: Earth's Gravity Results

Abstract

The constrained vapor bubble experiment scheduled to fly aboard the International Space Station in the near future promises to give us new insight into the fundamental science of interfacial thermophysics. The evaporating meniscus formed at the corner of the vapor bubble is expected to behave in a significantly different manner in the microgravity environment as compared with the Earth's gravity environment. Since the constrained vapor bubble can also behave as a micro heat pipe, it will additionally help in gaining a technical understanding of the performance of a micro heat pipe in a space environment. Earth-based experiments have been conducted for the past two decades to gain a better knowledge of the rich phenomenon observed in the relatively simple constrained vapor bubble setup. Here, some recent Earth's-gravity-environment-based data obtained on a 30-mm-long constrained vapor bubble have been presented. The data were fitted to a model, and a self-consistent value of the inside heat transfer coefficient was obtained. The external convective and radiative heat transfer coefficients were also determined. These ground-based experiments form a calibration against which the future data from space-based experiments will be compared.