冷库库门的非稳态RANS模型渗风研究

Study on Infiltration Through Doorway of Cold Store based on Unsteady RANS Model

伴随冷库总量的快速增长,冷库的能耗问题已越来越受到关注。库门渗风作为冷库的一项占比很大的热负荷是冷库能耗研究的一个重点。本文采用非稳态RANS模型对库门渗风建立了动态模拟模型,利用对一座库高和门高之比为2∶1的冷库,在不同库内外温差和冷风机运行模式下,验证实测数据结果表明:所建模型预测的渗风量、测量点当地风速和温度的数值和变化趋势都与实验值有较好的吻合,在开门时间40 s内时,渗风量模拟误差在±10%以内。利用该模型对渗风的特性和机理进行了模拟分析,结果表明,受风机水平方向风场影响,风机开时库内温度均比风机关时低。库内外空气密度差较小,库内冷空气受重力的影响不大,因此渗风量随开门时间呈线性变化。

Because the total gross of cold stores is increasing, the energy consumption of cold stores is attracting increasing attention. Infiltration through the doorway, which accounts for a large part of the total heat load, has become an important research focus with regard to the energy consumption of the cold store. In this paper, by using an unsteady RANS model, a transient infiltration simulation model is established. By utilizing a cold store with height ratio between the cold store and the door 2： 1, experimentally measured data under conditions with different temperature differences and operation modes of the cooling fans are used to validate the model. The results show that the predicted value and change trends of the infiltration air volume, local wind speed, and temperature of the established model agree well with the experimental data. The predicted error for the infiltration air volume before 40 s of door-open time is ± 10%. By using this model, the characteristics and mechanism of the infiltration are analyzed. The results show that, owing to the effect of the airflow made by cooling fans, the temperature in the cold store when the fans are on is lower than that when the fans are off. There is little density differenee between the warm air and the cold air. The gravity imposed on the cold air has little variation. Thus, the infiltration air volume changes linearly with the door-open time.