保鲜运输车果蔬堆码方式对温度场影响的数值模拟

摘要

Temperature field is one of the factors to guarantee the quality of cargoes under fresh-keeping transportation. In order to investigate the temperature field distributions, the differential pressure experimental container with banana cargoes units was used as the research object, a 3d numerical calculated model of 1/4 dimension of the car body was built by using the porous model, SIMPLE algorithm and wall function method to simulated the three kinds of garden stuff stack methods, including the "blanks on both two sides and middle", "blanks on both sides" and "full load". The cloud charts of the temperature distributions on the symmetry sections in the container and on the surface of cargoes were obtained. Comparative analyses show that rational stack method can improve the distribution of temperature field and under "blanks on both two sides and middle" stack method, the heat exchange of the cold air and goods is better, and the temperature field ahead of container is more uniform compared to the "blanks on both sides" and "full load". Experimental results meet the simulation results well, where the deviation between simulation temperature and the average of test values is no more than 1.5℃. This study reveals the general rules of the temperature field in fresh-keeping transportation with controlled atmosphere, which can provide a reference for the optimization design and selection of reasonable stack methods in fresh-keeping transportation.%温度场是保障果蔬运输品质的重要因素之一.为了解温度场的分布规律,该文以基于差压原理的运输厢体为研究对象,采用香蕉为试验物料,建立厢体的1/4等比例三维紊流数值计算模型,结合有孔模型,采用SIMPLE算法和壁面函数法,对厢体中间两侧留空、两侧留空和满载等3种果蔬堆码方式的模型进行温度场的数值计算,得出了厢体内纵截面和横截面的温度以及货物表面的温度分布图.经对比分析发现,合理的货物堆码方式可以改善厢体内温度场的分布；中间两侧留空方式较两侧留空方式和满载方式相比较,冷空气与货物的热交换好,厢体温度场较均匀.经过试验验证,模拟值与测试值平均温度偏差均不超过1.5℃,试验结果与模拟结果吻合较好.该研究揭示了果蔬保鲜车厢体内部温度场分布的一般规律,对保鲜运输车的货物堆码方式以及结构优化设计等研究有一定的参考价值.