Numerical simulation of heat and mass transfer in heat exchange tubes based on action of interfacial slip

Abstract

The liquid flow close to the interface has received much attention recently, that is determined by interfacial slip action. In heat exchange tube, the thermal diffusion in the flowing boundary layer is also related to the interfacial flow state. However, the study of convective heat transfer mostly ignores the interfacial slip and medium thermal diffusion. In this study, the variation law of heat transfer efficiency and the actual interfacial concentration under the action of interfacial slip and thermal diffusion in the heat exchange tubes are reported. We find that the heat transfer efficiency of no slip reaches the highest, compared to no slip, that of negative slip significantly reduces (at −0.99 mm, copper: −79.56%; aluminum alloy: −78.60%; carbon steel: −75.85%), and that of positive slip slightly reduces (at 0.58 mm, copper: −16.87%; aluminum alloy: −15.66%; carbon steel: −9.82%). As the slip length increases, the interfacial concentration of positive slip tends to the initial concentration, while the concentration changes rate of negative slip increases (at −0.99 mm, H2SO4: 110.29%, NaCl: 45.90%, C2H6O: −28.37%). These results show that the interfacial slip not only affects heat transfer performance but also interfacial concentration, and further affecting the metal corrosion behavior at the heat transfer interface.