Thermal Boundary Conditions on the Cross Sections Normal to the Main Flow of a Fully Developed Convection in a Tube with Tape Insert

Abstract

Reasonable thermal boundary conditions are very necessary for a numerical analysis to achieve reasonable results. When conjugated heat transfer is considered, it is very hard to specify the thermal boundary conditions on the inlet and outlet sections of the solid regions. As an example, the case of a tube with tape insert is studied. Based on results obtained by the model that simulates the fluid flow and heat transfer from entrance region to fully developed region, the characteristics of temperature distribution on the cross sections of the tube wall, the tape and the fluid flow in a tube with tape insert are analyzed. Then, the nondimensional temperatures having the characteristics of zero gradient along the main stream direction in the tube, the tape and the fluid regions are found. To check the correctness and usefulness of the defined nondimensional temperatures, the results obtained by the model from developing into a fully developed region are compared with those of the fully developed model. The results reveal that there exist the above-mentioned nondimensional temperatures in the fully developed region, which can be used to specify the thermal boundary conditions on the cross sections of the solids along the main stream direction.