风机参数对立体冷库气流组织影响的数值模拟

Numerical simulation of the effect of fan parameters on the airflow organization of a stereoscopic cold storage

为使立体冷库温度场更加均匀,研究立体库气流组织不同工况下的变化规律。利用FLUENT软件分别对冷风机送风速度在3.7~15.7 m/s、送风温度在240~248 K以及6种摆放位置下立体库内气流流动与传热过程进行数值模拟,并据此探析立体库气流组织特征分布及冷却性能指标。结果表明,风速对立体冷库性能影响显著,预冷时间随风速增加呈指数减小,温度场分布更均匀,但在冷藏阶段风速过大会造成气流扰动,温度场均匀性降低且能耗骤升;送风温度变化对气流组织分布无显著影响,与冷却速率呈反比关系,增幅基本一致;风机摆放采用主流背向式,气流干扰小且温度场降温均匀。立体冷库风机风速优选12.7 m/s,风温高于冷藏温度2 K,可保证降温速率与降温均匀特性,摆放形式优先采用主流背向式,温度场波动范围为-1~1 K,缩短了冷库在无装载情况下的开机预冷时间。研究结果有利于提高冷库冷却性能和货物冷藏品质,可为立体冷库内气流组织设计方案提供参考。

In order to make the temperature field of the stereoscopic cold storage more uniform,the change law of the airflow organization of the stereoscopic cold storage under different working conditions was studied.The airflow and heat transfer processes in the stereoscopic cold storage were numerically simulated by using FLUENT software with the air velocity of 3.7~15.7 m/s,the air temperature of 240~248 K and six placement positions,and the distribution of airflow organization characteristic and cooling performance index of the stereoscopic cold storage were explored accordingly.The results show that the wind speed has a significant impact on the performance of the stereoscopic cold storage.The pre-cooling time is exponentially reduced with the increase in wind speed,the temperature field distribution is more uniform,but in the cold storage stage,excessive wind speed will cause airflow disturbance,reduce the temperature field uniformity and sharply increase energy consumption;Air supply temperature changes have no significant impact on the distribution of airflow organization,and is inversely proportional to the cooling rate,with a basically consistent increase;The fan is placed in a mainstream back-to-back style,with minimal airflow interference and uniform temperature field cooling.The optimal wind speed of the fan in the stereoscopic cold storage is 12.7 m/s,and the air temperature is 2 K higher than the refrigeration temperature,which can ensure the cooling rate and uniform cooling characteristics.The optimal installation method is mainstream back facing style,and the temperature field fluctuation does not exceed±1 K,reducing the pre-cooling time of this type of cold storage when starting without loading.The research results provide a reference for the design scheme of airflow organization in the stereoscopic cold storage,which is conducive to improving the cooling performance of cold storage and the cold storage quality of goods.