Saturated film boiling at various gravity levels under the influence of electrohydrodynamic forces

Abstract

The present work is focused on the analyses of the bubble growth and heat transfer characteristics in saturated film boiling at various levels of gravity. In addition to this, the occurrence of self-similarity in interface structures during the bubble growth is examined. The phenomenon of bubble growth is strongly influenced by the buoyant forces due to gravity and its dominant effect is found to be replaced by the electrohydrodynamic forces in reduced gravity conditions. The decrease in gravitational acceleration results in increasing the characteristic wavelength and time scale. The bubble volume and maximum height before pinch-off thus increase enormously as the gravity value is reduced. The bubble pinch-off velocity is found to be decreased significantly in the case of reduced gravity condition. Heat transfer rate deteriorates in reduced gravity conditions which can be recovered by the externally imposed electric field. The dominance of electric field on the heat transfer rate is found to be more in reduced gravity condition. However, as the value of imposed electric field is enhanced, the difference in the effect of increasing heat flux tends to reduce.