To study the mechanism of evaporation and dynamics of the joint motion of a thin liquid film and the co-current vapor flow in a microchannel at local heating, a new three-dimensional non-stationary two-sided mathematical model has been proposed. The model takes into account the deformable gas–liquid interface, transfer of heat by liquid and vapor flow, heat loses due to evaporation, thermal conductivity in layers, as well as the temperature dependence of surface tension and liquid viscosity. Assuming the lubrication theory to be valid, the problem has been reduced to four governing equations for the film thickness, temperature fields in the vapor and liquid, and vapor pressure. The significant effect of heater length in the longitudinal direction on the film deformations and evaporation is shown numerically. The calculations show that there is an essentially nonlinear dependence of the minimum film thickness and maximum temperature on the length of the heater at the vapor–liquid interface. It has been found that the average evaporation intensity in all areas of the calculations may practically depend linearly on the length of the heating element.
|Журнал||Interfacial Phenomena and Heat Transfer|
|Состояние||Опубликовано - 1 янв 2017|