Numerical investigation on conjugated heat transfer of conduction in wall and mixed convection

The conjugated heat transfer of heat conduction in the wall and air mixed convection in tubes was numerically simulated with the SIMPLER algorithm and a new simplified method developed for dealing with conjugated problems. The results show that the circumferential conductive heat of the duct plate moves in both clockwise and anticlockwise directions, and the temperature difference of each plate is less than 0.5°C. In the axial direction, the maximum conductive heat flux occurs at the places where the axial non-dimensional length equals 2-4. The average Nusselt number increases with the Reynolds number and the inclination angle of the tube, and the optimum inclination angle is a variable value from -30° to 0°. However, the average Nusselt number is almost independent of the inclination angle when Re>1500. The numerical results are in reasonably good agreement with the experimental data with the deviations within ±28.7%.