Study on condensation flow and heat transfer characteristics of multicomponent mixture in dimple tube

Abstract

The flow and heat transfer characteristics of methane/propane and methane/ethane/propane have been numerically investigated in the dimple tube. The effect of mass flux, saturation pressure and composition ratio on the characteristics of flow, heat transfer and void fraction are examined. The results indicate that the heat transfer coefficient, friction pressure drop increase with the increase of mass flux and decrease with the pressure drop increased. The heat transfer coefficient of a binary mixture is higher than that of ternary mixture under the same condition. The friction pressure drop of the ternary mixture is greater than that of the binary mixture at high vapor quality. In addition, the influence of geometric parameters is discussed. Higher dimple depth and lower pitch will result in higher heat transfer efficiency. The dimple tube with r = 0.75 mm, p = 5.08 mm, e = 4.33 mm have the best heat transfer performance, and the surface performance factor PFS and the performance factor enhancement PFE are 1.041–1.304 and 0.885, respectively. Besides, the simulation result of void fraction, heat transfer coefficient and friction pressure drop are compared with some general models. Finally, an improved pressure drop model for the enhanced tube is proposed.