Microgravity: Effect of a Moving Local Heater on Liquid Film Structure

Abstract

The paper presents theoretical analysis of a moving local heater effect on the structure of a thin liquid layer on horizontal substrate or under the zero-gravity condition. The 2-D problem is considered with use of long-wave approximation. For the case of small Reynolds numbers the steady-state equation is derived for description of the liquid film deformation in the accompanying frame of reference. The obtained equation can be applied in particular at microgravity condition or for horizontal substrate orientation. The results of presented simulations describe the film thickness, pressure and liquid velocity at a given temperature distribution on a free surface. The dependencies of viscosity and density on the temperature are neglected in the model; heat, mass and momentum transfer between the liquid and gas phases at the free surface are also disregarded. It is shown that under the zero-gravity condition the motion of local heater provides the existence of steady-state regime without film breakdown and dry spot formation. As outcome we have theoretical background for new scheme of experiment on the study of phenomena in non-isothermal liquid films under the microgravity conditions.