Experiment and Modeling of Cryogenic Spray Chilldown Heat Transfer of a Metal Plate in Martian Gravity and Microgravity

Abstract For the past eighty years, cryogenic chemical propulsion has played a major role in space missions, and it will continue to be an indispensable unit in a spacecraft. The development of cryogenic rocket engines for space missions and the planned space fuel depots for deployment in the Lower-Earth-Orbit (LEO) for lunar and Mars future missions all start with the research of cryogenic propellant thermal-fluid management systems. One of the key elements is the chilldown of the propellant storage tank from room temperature to cryogenic liquid temperature during tank-to-tank propellant transfer in space. Based on that need, the current authors have conducted research to develop an emerging method to maximize the chilldown efficiency and minimize propellant consumption during propellant storage tank chilldown process. In this paper, we report on the experimentation of a spray quenching process of a circular metal plate with low-thermal conductivity coating in Martian gravity and microgravity conditions. Additionally, detailed mathematical modeling is presented on the quenching film boiling regime and Leidenfrost temperature with respect to system parameters such as spray cooling flow rate, spray fluid thermal properties, and specific location on the test plate. This paper presents the first Martian and microgravity cryogenic storage tank chilldown experimental data and empirical correlations for chilldown film boiling heat transfer coefficient and rewet temperature (Leidenfrost point). To quantitatively evaluate the spray quenching effectiveness, a chilldown efficiency is defined and used to distinguish the effects of gravity and plate surface coating.