Effects of an Air Curtain on the Temperature Distribution in Refrigerated Vehicles Under a Hot Climate Condition
Effects of an Air Curtain on the Temperature Distribution in Refrigerated Vehicles Under a Hot Climate Condition
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DOI：
10.1115/1.4043467
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发表时间：
2019-05
影响因子：
2.1
通讯作者：
L. Cong;Qinghua Yu;G. Qiao;Yongliang Li;Yulong Ding
中科院分区：
文献类型：
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作者：
L. Cong;Qinghua Yu;G. Qiao;Yongliang Li;Yulong Ding
冷藏车在冷链应用中起着至关重要的作用。它直接影响到专门易腐商品的质量和保质期。然而，在部分卸载期间由通过打开的门的自然对流引起的冷能耗散打破了等温冷环境并且显著地升高了冷藏集装箱内的空气温度。这种温度升高对剩余的食物有害。在本研究中，在集装箱门口附近引入空气幕，试图减少部分卸载引起的冷能耗散。建立了数值模型，探讨了空气幕的气流速度、喷嘴宽度和喷射角度等关键参数对冷藏集装箱开门后内部空气流动和温度变化的影响。数值结果表明，要形成稳定有效的空气幕，防止内部冷能损失或外部热空气入侵，需要对关键参数进行调整。当射流速度为2 m/s，喷嘴宽度为7.5 cm，射流角度为0 ° ~ 15 °时，可形成有效稳定的空气幕，使开门后室内空气温度仅从初始温度5 °C上升约3 °C。研究结果对在冷藏车中引入有效的气幕以避免冷链运输失败具有重要的指导意义。
Refrigerated vehicle plays an essential role in the cold-chain applications. It directly affects the quality and shelf life of specialized perishable goods. However, the cold energy dissipation caused by natural convection through an open door during partial unloading breaks the isothermal cold environment and notably elevates the air temperature inside the refrigerated container. This temperature rise is harmful to the remaining food. In this study, an air curtain was introduced near the container doorway to attempt to reduce the cold energy dissipation caused by partial unloading. A numerical model was established to explore the effects of the key parameters of the air curtain such as the airflow rate, nozzle width, and jet angle on the air flow and temperature evolution inside the refrigerated container after the door is opened. The numerical results show that the key parameters need to be tailored to form a stable and effective air curtain for preventing the internal cold energy loss or external hot air invasion. An effective and stable air curtain was formed to make the inner air temperature increase only by about 3 °C from the initial temperature of 5 °C after the door was opened, when the jet velocity was set to 2 m/s, the nozzle width was set as 7.5 cm, and the jet angle was set between 0 deg and 15 deg. This work can offer significant guidance for the introduction of an effective air curtain in a refrigerated vehicle to avoid the failure of cold-chain transportation.