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对于Baldwin和Lomax代数湍流模型的两个主要缺点,即不同流动情况下长度尺度的不确定性以及尾迹区处理的模糊性,本文进行了针对性的改进.在固壁区域,采用基于函数值的加权平均方法计算长度尺度;在尾迹区,基于熵包线的概念来确定尾迹中心线和确定搜索范围.同时还提出了若干增强模型稳定性的措施.将所改进模型用于复杂的叶轮机械内流问题,分别以二维和三维压气机转子为算例,进行了改进模型的验证以及与基准模型进行了比较.结果发现,改进的模型能够正确地模拟物理现象,具有更高的精度,同时也提升了求解器的收敛性.
For two major shortcomings of Baldwin and Lomax algebraic turbulence models, namely, the uncertainty of length scale under different flow conditions and the fuzziness of wake area processing, some improvements are made in this paper.In the solid wall area, Weighted average method is used to calculate the length scale. At the wake area, the concept of entropy envelope is used to determine the center line of wake and to determine the search range. Several measures to enhance the stability of the model are also proposed. The improved model is used in complex impeller Flow problems, two-dimensional and three-dimensional compressor rotors are taken as an example to verify the improved model and compare with the benchmark model.The results show that the improved model can accurately simulate the physical phenomena with higher accuracy, at the same time It also improves the solver’s convergence.