NUCLEATE AND FILM BOILING IN REDUCED GRAVITY FROM HORIZONTAL AND VERTICAL WIRES

摘要

Nucleate boiling was studied experimentally from electrically heated hori¬zontal and vertical wires (0.0197-in. diam.) in water, ethyl alcohol, and 60-percent-by-weight aqueous sucrose solution in gravity fields of 0.014 and 1.0 times Earth gravity. The fluids were at their saturation temperatures at atmospheric pressure. The gravity reduction to 0.014 times Earth gravity caused a shift of only a few degrees in the curve of heat flux as a function of the difference between surface and saturation temperatures.nFilm boiling of ethyl alcohol was observed at Earth gravity and at several reduced gravity fields down to 0.014 times Earth gravity. For both the hori¬zontal and the vertical orientations, the gravity field and the circumferential surface tension at the interface of the vapor film surrounding the thin wire proved to be very important for the determination of the vapor removal pattern. As gravity was reduced, the vapor film behavior for the vertical orientation approached that for the horizontal position. A motion picture film is avail¬able that illustrates the boiling behavior in reduced gravity.