送风速度对结球生菜压差预冷性能的影响

Effect of Air Supply Speed on the Forced Air Cooling Performance of Lettuce

为探究不同送风速度对结球生菜压差预冷性能的影响,以筐装结球生菜为研究对象,建立筐体、菜品的三维模型,将菜品的呼吸热、蒸腾热、冷凝热作为菜品区域内热源,采用计算流体力学数值模拟方法,研究压差预冷过程中不同送风速度下结球生菜的预冷效果,并进行模型验证。结果表明,菜品中心温度模拟值与实验值的变化趋势一致,温度最高偏差小于1.9℃,其均方根误差最大为1.0℃。预冷时间随风速的增加逐渐减小,且随着风速的增大,预冷时间减少的幅度逐渐缩小;风速对风机能耗影响较大,风机能耗随着风速增大而持续增大,综合考虑建议筐装结球生菜预冷采用2 m/s的送风速度较为适宜。

In order to explore the effect of different air velocity on the pressure difference precooling process of lettuce,taking the framed head lettuce as the research object,the three-dimensional model of the frame and the dish was established.Considering the respiratory heat,transpiration heat and condensation heat of the dish,the precooling process of the head lettuce under different working conditions was simulated using CFD simulation technology.The data analysis showed that the simulation value was basically consistent with the experimental value,and the maximum deviation was not more than 1.9℃,the maximum root-mean-square deviation was 1.0℃.The cooling time decreased with the increase of wind speed.When the wind speed reached a certain value,the decreasing range of the cooling time decreased gradually.The wind speed had a great impact on the energy consumption of the fan.With the increase of the wind speed,the energy consumption of the fan continued to increase,and the extent of increase continued to increase.After comprehensive consideration,it was recommended to adopt a 2 m/s air supply speed for the precooling of basket packed lettuce.