板翅式换热器热通道结霜过程的数值模拟

To study the frost growth rule in the hot channel of plate-fin heat exchangers under different working conditions, a frosting model based on Lewis heat and mass transfer analogy theory is established and then combined with the unsteady heat transfer model of plate-fin heat exchanger. First, the accuracy of the model is verified on the test rig for frosting visualization on flat surface. Then, the mass and starting positions of frost at inlet humid air flowing speeds of 0.8 m/s, 1.2 m/s and 2.0 m/s and relative humidities of 60%, 70% and 80% are compared, respectively. The results show that the higher the air velocity, the faster the frost growth rate and the smaller the frost area. Also, the higher the relative humidity of air, the faster the frost growth rate and the larger the frost area. Meanwhile, with the increase of the frost layer thickness, the pressure drop of the channel continues to increase, and the efficiency of the plate-fin heat exchanger decreases. When the average thickness of the frost layer accumulates to 1.5 mm in the hot channel, the efficiency of the heat exchanger decreases by about 10%.