风冷冰箱非均匀翅片管换热器结霜特性实验研究OA

Frosting on the evaporator of frost-free refrigerators is a critical factor hindering the efficient operation of refrigeration systems.In the paper,a vertical wind tunnel frosting test experimental setup was established,and the frost growth characteristics of fin-tube heat exchangers with non-uniform fin spaces were investigated,the frosting characteristics at incoming air temperature below 0℃were explored.Firstly,the local frosting characteristics of non-uniform fin-tube heat exchangers at different air temperatures were analyzed.Then the effects of windward velocity,air temperature,and relative humidity on frost mass,frost density,heat transfer rate and other parameters were explored.Finally,through sensitivity analysis method,a comprehensive evaluation of influencing factors was conducted.The results indicate that frost thickness distribution remains uniform in different regions during initial frosting stage,whereas frost thickness in windward regions shows higher growth rate during later stage.In large fin space region,the frost cannot completely blockage fin space even at the end of frosting time.Increasing air temperature can enhance frost density,within the range of ‒15℃to ‒5℃.Furthermore,the air relative humidity has minimal effect on frost accumulation.At windward velocity of 1 m/s,frost mass increases by 50％and initial heat transfer rate increases by 66.7％compared with those on 0.5 m/s condition.Frosting rate and air-side pressure drop are mostly influenced by air moisture content,with contributions of 49.9％and 45.6％,respectively.Heat transfer temperature difference and windward velocity substantially affect evaporator's cooling capacity,with contributions of 35.4％and 29.4％,respectively.The results can provide guideline for evaporator design and optimization under frosting condition.