Vaporization in non-azeotropic and azeotropic alcohol-water mixtures at a flow in a heated circular channel

Studies of hydrodynamics and heat exchange of an alcohol-water mixture during its circulation through a heated cylindrical channel are carried out. Non-azeotropic and azeotropic mixtures with a mass concentration of a volatile component of 22 and 95 %, respectively, are used as the working fluid. The experiments are realized at a pressure of 0.018-0.02 MPa. The working section is made of stainless-steel pipe with an outer diameter of 8 mm and a length of 4 m. For visual observation of the composition of the two-phase flow, an optical section installed behind the working section is used. Experiments show that the formation of a vapor phase during the circulation of a non-azeotropic mixture through a heated channel begins at a wall temperature below the equilibrium temperature of the mixture. The governing condition for vaporization is the excess of the wall temperature over the equilibrium temperature of the volatile component.