Experimental study of bubble behavior and local heat flux in pool boiling under variable gravitational conditions

This paper presents the results of a nucleate boiling experiment performed in the framework of the 42nd European Space Agency parabolic flight campaign. Nucleate boiling of FC-72 was established at a single artificial cavity on a thin stainless steel heating foil. The bubble shape and the temperature distribution of the heating foil were measured via high-speed imaging and infrared thermography at different gravity levels and during transition phases between these levels. The influence of gravity on bubble frequency and departure diameter was evaluated. The transient heat flux distribution was calculated by applying an energy balance at each pixel of the infrared temperature image. This heat flux distribution is presented for a complete bubble cycle (growing, detachment and rise), bubble coalescence, and satellite bubble merger