微细管束换热器结霜及流动对流换热特性实验研究

利用可视化换热器性能实验台测试了微细管束表面在无换热、大温差、凝露条件下不同风速工况的流动损失与空气侧换热系数。同时探究了超低温工况下，相对湿度和风速对微细管束换热器流动换热特性影响。相对湿度增大，湿空气释放潜热增加，结霜量增大，换热器前后压损增加。高速气流具有剪切作用，风速增大会导致结霜迟滞。

Frost experimental investigation on frost and characteristics of flow and heat transfer of fine tube bundle

A visualization bench for testing performance of heat exchanger was designed to measure the pressure drop of the air flow and air-side heat transfer coefficient of the fine tube bundle at different wind speeds under the condition of no heat transfer, large temperature difference and condensation. The effects of relative humidity and wind speed on characteristics of flow and heat transfer of finetube bundle were also investigated at ultra-low temperature. The latent heat of humid air became larger with increasing relative humidity. At the same time, the frost thickness on the tube surface was thicker so that the pressure loss of air flow increased. Because the effect of high-speed air shear on the frosting process was apparent, the higher wind speed would lead the frosting time delayed.