新型铁路冷藏集装箱风道设计与温度场分析

Air Duct Design and Temperature Field Analysis of a Novel Railway Refrigerated Container

目的对新型铁路冷藏集装箱的风道进行优化设计,并考察其使用效果。方法运用CFD技术,构建新型铁路冷藏集装箱模型,并对不同风道长度条件下的车内温度场、气流场进行分析。对试验样车进行实际对比测试,以验证设计和运用效果。结果对于大空间、长跨度的车体,适当加长送风道能有效改善车箱内部气流组织状况。与短风道(风道长度为车箱长度的1/4)相比,采用长风道(风道长度为车箱长度的2/3)时,速度不均匀系数减少了37.5%,温度不均匀系数减少了27.3%。在此基础上进一步展开分析后确定,对于40英尺(1英尺=0.3048 m)冷藏集装箱而言,当风道长度为9.5 m时,车内温度场分布效果最优,速度不均匀系数为0.511,温度不均匀系数为0.0008,不同位置间的最大温差为1.1℃左右;不同时刻间,各截面的平均温度在0.3℃以内波动,满足冷藏运输装备的设计运行要求。试验表明,所建仿真模型可较好地反映实际的运输状况,实测温度与模拟温度的最大差值在0.8℃以内,总体偏差合理。通过模型可直观地分析车箱温度的分布情况,为研究提供了便利。结论适当加长送风道能有效改善车箱内部气流组织状况;对于新型40英尺铁路冷藏集装箱而言,当风道长度为9.5 m时,车内气流组织效果最优。

The work aims to conduct optimal design on air duct of novel railway refrigerated container and test its using effect.In this paper,the CFD simulation software was used to build a new model of railway refrigerated container to analyze the temperature field and air flow field in the vehicle under different length of air duct.After that,the actual comparative test was carried out with the test sample vehicle to verify the application effect of design.The results showed that,for vehicle of large space and long span,the air distribution can be effectively improved by lengthening the air supply duct properly.Compared with the short air duct(the length of the air duct was 1/4 of the length of the carriage),when the long air duct was used(the length of the air duct was 2/3 of the length of the carriage),the speed non-uniformity coefficient was reduced by 37.5%,and the temperature non-uniformity coefficient was reduced by 27.3%.On this basis,further analysis was carried out and it was finally determined that for 40-foot(1 foot=0.3048 m) reefer container,when the length of air duct was 9.5 m,the effect of temperature field distribution in the vehicle was the best.At this time,the velocity non-uniformity coefficient was 0.511,the temperature non-uniformity coefficient was 0.0008,and the maximum temperature difference between different positions was about 1.1℃.At different times,the average temperature of each section was within 0.3℃,which met the design requirements of refrigerated transportation equipment standard.The test showed that the simulation model can better reflect the actual transportation situation,the maximum difference between the measured temperature and the simulated temperature was within 0.8℃,and the overall deviation was reasonable.Through the model,the temperature distribution of the carriage can be analyzed intuitively,which providedconvenience for the research.Appropriately lengthening the air duct can effectively improve the air distribution in the carriage.For the new40-foot railway refrigerated container,when the air duct is 9.5 m,the air distribution in the car is the best.