An Experimental Study of Boiling in Reduced and Zero Gravity Fields

Abstract

One of the most important environmental changes which man encounters as he leaves the earth is the change in the gravity field. In free space or in an orbiting satellite, the gravitational field may closely approach zero. On the surface of the moon or the inner planets of our solar system, the gravitational field is less than that on earth. Heat-transfer processes such as free convection, condensation and boiling depend on the gravitational body force, and hence will be affected by this new environment. As yet, to the authors’ knowledge, there has been no experimental heat-transfer information available for reduced gravity fields. Hence any design calculations for this range must be based upon extrapolated theories which contain a gravity parameter, but which have only been checked experimentally at normal gravity. For very low gravity fields, these theories may become inaccurate, since forces such as surface tension, which are sometimes neglected, become increasingly important as the body force is reduced. In a previous photographic study of boiling in the absence of gravity,1 the authors demonstrated the importance of gravity in the pool-boiling mechanism.