基于非稳态喷淋水液膜的间接蒸发冷却传热传质模型开发OA

To improve the accuracy of the heat and mass transfer mathematical model for indirect evaporative cooling(IEC),a set of heat and mass transfer equations considering the coupled convection and conduction processes of the spray water liquid film was established.Based on the variation of spray water flow rate,the relationship between liquid film velocity and thickness was derived,and the influence of liquid film velocity and thickness on IEC performance was simulated.The accuracy of the model was validated using experimental results.The results indicate that compared with the original model,the proposed modified model improves the prediction accuracy of the air state parameters on the secondary side by up to 5.57%.When the spray water liquid film velocity increases from 0.1 m/s to 0.4 m/s,the wet-bulb efficiency and enthalpy efficiency increase significantly from 51%and 50%to 54%and 53%,respectively.When the velocity continues to increase to 0.9 m/s,the growth of wet-bulb efficiency and enthalpy efficiency slows down,eventually reaching 56%and 55%,respectively.When the liquid film thickness increases from 0.1 mm to 0.4 mm,the wet-bulb efficiency and enthalpy efficiency drop sharply from 0.81 and 0.90 to 0.59 and 0.52,respectively.As the spray water liquid film velocity increases,both the system enthalpy efficiency and wet-bulb efficiency increase.As the spray water liquid film thickness increases,the thermal conduction resistance increases,and the heat transfer effect is weakened.This study can provide data support for the optimal design of spray water systems in indirect evaporative coolers.