Modeling and Numerical Simulation of Axial Fan for Dry-Wet Combined Cooling System

The performance of the fan determines the thermal performance of the combined dry and wet cooling system, but its structure is complex and difficult to express with an accurate mathematical model. This paper takes the axial fan as the research object and combines its structural parameters and characteristic curves to establish an accurate single-channel numerical model of the fan. Based on this, the tangential and radial velocity changes of the airflow passing through the fan are studied, and analyze the influence of fan rotation on the direction of outlet airflow. A piecewise function fitting method with r (the distance between the calculation area and the fan axis) as the independent variable and the tangential and radial velocity at the outlet surface of the fan as dependent variables is proposed to simplify the model. The results show that in the outlet section of the fan, the tangential velocity of the fluid is 1/5 of the speed of the rotating section, and generally decreases with the increase of the distance from the outlet surface, while the tangential velocity of the fluid changes little. In addition, under the same tangent plane, the speed is distributed in a hierarchy with r, which is highly coincident with the fitted curve. The error of the calculation result is less than 2.7%. The model has high reliability. It provides a better idea for the calculation of the coupled fan of the air cooling system.