不同构造冷藏车厢体的冷却性能模拟与对比

Simulation and Comparison of Cooling Performances of Refrigerated Vehicles with Different Structures

本文针对4种结构不同的冷藏车厢体,在相同的运输时间下采用同样货物堆码方式,以苹果为实验材料,利用CFD模拟4种厢体在特定风速、特定制冷温度下其内部温度分布情况,并对厢体冷却性能(温度分布、冷却时间、冷却均匀性)进行对比与分析。经过模拟180 min的冷藏运输结果表明:同时安装侧通风槽及地导轨与单独安装侧通风槽的厢体内部货物温度变异系数分别为0.001 3、0.001 5,冷藏运输后温度在3~4.5℃范围内的货物比重分别为62.06%、59.26%,货物平均温度分别为4.3℃、4.6℃;无导轨型厢体与单独加装地导轨厢体货物的温度变异系数分别为0.002 4、0.002 1,冷藏运输后温度在3~4.5℃范围内的货物比重分别为52.54%、53.44%,货物平均温度分别为5.0℃、4.9℃。结果表明:温度的最大均方根误差分别为0.221℃、0.198℃,最大平均相对误差为18.35%、16.91%,风速模拟值与实测值的最大偏差为0.3 m/s,得出实验值与模拟值有较好的一致性。

The reasonable optimization and improvement of the structure of the refrigerated compartment plays an important role in efficiently improving the cooling effect of a refrigerated truck,which ensures the quality and safety of the goods during refrigerated transport.It is also an effective way to deal with the needs of cold chain suppliers.In this study,four kinds of refrigerated trucks with the same working conditions but different structures were examined,with apples used as the test material and based on the same goods stack.Computational fluid dynamics simulations were used for the internal temperature distributions of the four compartments under specific wind speed and cooling temperature conditions.The cooling performances(temperature distribution,cooling time,cooling uniformity)of the four refrigerated trucks were compared and analyzed.The results showed that the installation of both a side ventilation trough and ground rail was the best way to improve the cooling performance of refrigerated trucks.The coefficient of temperature variation was0.0013,with62.06%of the goods were within a temperature range of3-4.5However,there was no obvious improvement in the cooling performance compared with the single installation of a side ventilation trough,where the coefficient of temperature variation was0.0015,and59.26%of the goods were within a temperature range of3-4.5However,compared with the single installation of the guide rail,the single side ventilation trough could significantly reduce the cooling time and improve the cooling uniformity.Compared with a refrigerated truck with no guide rail,although there was no obvious reduction in the cooling time,the installation of the guide rail by itself could improve the uniform cooling of the cargo.The coefficient of temperature variation for the single installation of the guide rail was0.0021,and the coefficient of temperature variation of the no guide rail was0.0024.A comparison of the experimental and simulated values for the wind speed and temperature showed good agreement,with temperature maximum root mean square errors of0.221and0.198,respectively,and maximum average relative errors of18.35%and16.91%,respectively.The maximum air speed deviation between the simulated and measured values was0.3m/s.This study provided some reference values for the optimization of different cold chain requirements to ensure the quality and safety of agricultural products during refrigerated transportation.