低温冷风机结霜特性的研究及其融霜方法的改进

以华中地区某禽类加工厂冻结间的冷风机为研究对象，建立数学模型，对结霜工况下冷风机运行特性进行了理论分析。模型和实验测得的霜层厚度的平均偏差8．99％，吻合较好。阐述了随着霜层的生长，空气冷却器的传热面积、传热系数以及空气侧压降的变化规律。进一步分析了冻结间内空气相对湿度、冷风机进口空气干球温度以及迎面风速等对霜层生长的影响。并遵循尽量减少初投资、节能、实用为选择改进的原则，结合企业生产工序及冻结间运行的实际情况，对原融霜方式提出改进方案。

Investigation of the Frosting Performance and Improvement of the Defrosting Method for an Air-cooler under Low Temperature Condition

A theoretical analysis was carried out and a mathematical model was proposed for air - cooler frosting performance. The comparison of the calculated thickness Of the frost layer shows good agreement with the experimental data. The average difference is 8.99%. Further studies were carried out on the factors affecting heat transfer surface, the coefficient of heat transfer and the air side pressure drop during a frosting process. The characteristics of frost growth were analyzed under different inlet air temperature, relative humidity and velocity. The calculated results show that the inlet air temperature and the relative humidity of the inlet air have obvious influence on the frosting. Disadvantages of the present defrosting methods were analyzed. In order to reduce the first cost and energy consumption of the refrigeration system for a cold - storage enterprise, an improved method of defrosting for an ammonia air - cooler was proposed. It was proved that the improved method is practical for improving the energy saving, lowering manufacture cost and enhancing economical benefits.