XIA B, LIANG X G, XU X H. Two-dimensional simulations of frost formation on a cold tube under strong convection by using the p-VOF method[J]. Acta Aerodynamica Sinica, 2022, 40(5): 91−99. doi: 10.7638/kqdlxxb-2021.0074
Citation: XIA B, LIANG X G, XU X H. Two-dimensional simulations of frost formation on a cold tube under strong convection by using the p-VOF method[J]. Acta Aerodynamica Sinica, 2022, 40(5): 91−99. doi: 10.7638/kqdlxxb-2021.0074

Two-dimensional simulations of frost formation on a cold tube under strong convection by using the p-VOF method

  • The pre-cooling heat exchanger is an important component of a new type of hypersonic engine, which cools the high-temperature intake air to −130℃ to increase the airflow rate and improve engine performance. However, the frosting due to the water vapor in the atmosphere is a key factor restricting the application of pre-coolers in the new type engines. The flow velocity (above 10 m/s) through the pre-cooler is much faster than that in most frosting researches. The condition that the incoming air velocity is greater than 10 m/s can be considered as a strong convection condition. The frost layer is dense under strong convection, which is different from those with dendrite structures under natural convection or low-velocity conditions. A new frosting simulation method called p-VOF has been developed to simulate the frosting under strong convection conditions. This method is a pseudo VOF method for multiphase flow simulations with phase transition. It obtains the volume fraction change of the frost phase by explicitly solving the simplified mass conservation equation instead of the original volume fraction equation. The p-VOF method was used to simulate the two-dimensional frosting simulation on a cold tube under strong convection to confirm its applicability to simulate the frosting under such conditions. The general mechanism and characteristics of the frosting were analyzed. And the effects of air velocity, air humidity, and tube surface temperature on the frosting and flow were studied. Results showed that the higher the air humidity or the lower the tube surface temperature, the larger the frost growth rate and the thicker the frost layer. And higher air velocity leads to larger frost growth rate at the beginning of frosting, but earlier slowing down of the frost growth, yielding a thinner frost layer.
  • loading

Catalog

    /

    DownLoad:  Full-Size Img  PowerPoint
    Return
    Return