Analysis of falling film flow and heat transfer on an elliptical tube

Based on the volume of fluid algorithm and user-defined function, the flow and heat transfer of falling film on an elliptical transverse tube with different axis ratios was numerically studied. Simulation results are discussed based on the velocity, pressure, and temperature distribution of the liquid. According to the results, the liquid film pattern, heat and mass transfer of the liquid film are affected by the axis ratios: the liquid flow rate of the film outside the elliptical tube was faster compared with a circular tube; the simulated wall pressure gradually decreased along the flow direction and then rapidly recovered, and the position of the minimum pressure moved backwards with the increase of the axis ratio. Also, the distribution of local Nu along the wall was similar to the pressure distribution with the minimum value of X = 0.90. In general, the heat transfer of an elliptical tube performs best when the axis ratio is e = 1.65. The simulated Nu number distribution and film thickness were compared with published experimental data, which showed acceptable consistency.