装载机冷却系统流场均匀性的CFD分析

Field Uniformity Analysis of Loader Cooling System Based on CFD

运用CFD数值模拟技术,引入速度均匀性指数和速度变异系数的概念定量分析装载机冷却系统流场均匀性程度,利用速度矢量图、旋转涡量占比等值分布图分析装载机冷却系统流场不均匀的原因。研究表明,流场速度均匀性指数等于0.9时,与速度变异系数等于0.25时的流场均匀性相当,速度均匀性指数可以作为诊断流场是否均匀的标准;比较不同截面上的流场均匀性评价指标发现,散热舱内流场的均匀性在入口段表现优秀,在冷却风扇上下游却不合格,且均匀性程度沿冷却空气的流动路径逐渐降低;旋转涡量占比大是导致冷却系统流场不均匀的主要原因。试验测试结果验证了CFD数值模拟的可靠性,可为装载机冷却系统设计提供有效指导。

The flow field uniformity of the loader cooling system was analyzed quantitatively by using CFD numerical simulation technology and applying the concepts of velocity uniformity index and velocity variation coefficient.The reasons for the uneven flow field of the loader cooling system were qualitatively analyzed by using the velocity vector diagram and the equivalent distribution diagram of the rotating vorticity ratio.The results show that when the velocity uniformity index is equal to 0.9,the flow field uniformity is equivalent to the flow field uniformity when the velocity variation coefficient is equal to 0.25,and therefore,the velocity uniformity index can be used as a diagnostic standard for the uniformity of the flow field.By comparing the evaluation indexes of flow field uniformity on different sections,it is found that the degree of flow field uniformity in the cooling chamber decreases gradually with the flow path of cooling air.By drawing the equivalent cloud map of the rotating vorticity ratio and decompose the vortex structure,it is found that the large rotating vorticity ratio is the main reason for the uneven flow field of the cooling system.The test results verify the reliability of CFD numerical simulation.