Dynamics of propagation of a self-sustained evaporation front on the flat and cylindrical heaters

Abstract

The paper presents the results of experiments on freons R21 and R114 and their mixtures. The variation range of volatile component concentration is 0 <C <1. The propagation velocity of a self-sustaining evaporation front was studied. The experiments were carried out under the conditions of free convection at a temperature of saturation. The stainless steel tubes with the diameters of 3 and 8 mm and a flat section of 25 x 50 mm were used as the working sections. The experimental results showed that in the field of development of hydrodynamic instability of a vapor front, a higher velocity of front propagation corresponds to a higher concentration of volatile component. Experiments with different heater geometry showed that dependence of the evaporation front velocity on the temperature head for a cylindrical heater with a diameter of 3 mm almost coincides with the dependence for a flat heater. In the region of temperature heads corresponding to the loss of hydrodynamic stability of the evaporation front interface, an earlier development of instability is observed on a heater with a diameter of 8 mm.