Abstract:
Based on the experiments of eight plain tube bundle wet air cooling, a three-dimensional physical model of plain tube bundle was established. Hexahedral mesh generation and symmetric boundary were applied to the model. A mass source was applied to the tube surface to form liquid film based on the tube boundary condition of constant temperature. The Eulerian Wall Film (EWF) model was coupled with the mixture species transport model to study the heat and mass transfer between liquid film and air in wet air cooling. Six sets of different numbers of grids were divided, and grid independence test was done. The final division grid number was 793 152. The outlet temperature and moisture content of air passing through the tube bundle were obtained by numerical simulation. Compared with the experimental data, the simulated error of outlet air temperature was from -0.67% to -0.98%, while the simulated moisture content error is from -4.95% to 2.29%. The mass distribution of liquid film on the surface of tubes under different spray flow rates is compared. Under the condition of small spray flow, the liquid film is mainly distributed in the lower half of the tube wall. With the increase of spray water flow, the liquid film distribution in the tube wall tends to be uniform. Water film temperature increases firstly and then decreases from upper to lower tube bundle. Air in the leeward side of the tube bundle, due to the low flow rate, forms a triangular region with higher humidity and higher temperature. The simulated mass transfer coefficient between water film and air is lower than that of experiments, and the error is from -8.00% to -9.30%. The heat and mass transfer mechanism of wet air cooling is revealed by numerical simulation, which provides a theoretical basis for the design and transformation of air cooler.