EFFECT OF GAS MASS FLUX ON TWO-PHASE FLOW HEAT TRANSFER COEFFICIENTS IN A FLAT MICROCHANNEL UNDER LOCAL HEATING USING HIGH-SPEED SCHLIEREN VISUALIZATION

This article presents data of two-phase flow in a flat microchannel with schlieren high-speed visualization to investigate the effect of gas mass flux on heat transfer coefficients in the gas mass fluxes range from 0.074 to 14.89 kg/m<sup>2</sup>s. A dielectric liquid HFE-7100 was used as a working fluid, and high parity nitrogen was used as a working gas. The developed script in the MATLAB<sup>® </sup>is described and used to calculate quantitatively local characteristics of the flow, such as the areas occupied by liquid film-gas flow and the areas of dynamic dry spots. It has been shown that the growth of heat transfer coefficients with increasing gas mass flux associated with increasing of liquid film-gas flow areas, which indicates heat transfer enhancement during the evaporation of thin liquid film into dry gas. It has been also shown that decreasing of heat transfer coefficients with increasing gas mass flux associated with dynamic dry spots development.