Li Zhiyuan, Du Juan, Ottavy Xavier, Zhang Hongwu
Department of Physics, University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Engineering Thermphysics, Chinese Academy of Sciences, Beijing 100190, China.
Entropy (Basel). 2018 Jun 22;20(7):486. doi: 10.3390/e20070486.
A local loss model and an integral loss model are proposed to study the irreversible flow loss mechanism in a linear compressor cascade. The detached eddy simulation model based on the Menter shear stress transport turbulence model (SSTDES) was used to perform the high-fidelity simulations. The flow losses in the cascade with an incidence angle of 2°, 4° and 7° were analyzed. The contours of local loss coefficient can be explained well by the three-dimensional flow structures. The trend of flow loss varying with incidence angle predicted by integral loss is the same as that calculated by total pressure loss coefficient. The integral loss model was used to evaluate the irreversible loss generated in different regions and its varying trend with the flow condition. It as found that the boundary layer shear losses generated near the endwall, the pressure surface and the suction surface are almost identical for the three incidence angles. The secondary flow loss in the wake-flow and blade-passage regions changes dramatically with the flow condition due to the occurrence of corner stall. For this cascade, the secondary flow loss accounts for 26.1%, 48.3% and 64.3% of the total loss for the flow when the incidence angles are 2°, 4° and 7°, respectively. Lastly, the underlying reason for the variation of the secondary flow loss with the incidence angle is explained using the iso-surface method.
提出了一种局部损失模型和一种积分损失模型，以研究线性压缩机叶栅中的不可逆流动损失机制。基于门特尔剪切应力输运湍流模型（SSTDES）的分离涡模拟模型用于进行高保真模拟。分析了入射角为2°、4°和7°时叶栅中的流动损失。局部损失系数的等值线可以通过三维流动结构得到很好的解释。积分损失预测的流动损失随入射角变化的趋势与总压损失系数计算的趋势相同。积分损失模型用于评估不同区域产生的不可逆损失及其随流动条件的变化趋势。结果发现，对于这三种入射角，在端壁、压力面和吸力面附近产生的边界层剪切损失几乎相同。由于角区失速的发生，尾流和叶道区域的二次流动损失随流动条件变化显著。对于该叶栅，当入射角分别为2°、4°和7°时，二次流动损失分别占总损失的26.1%、48.3%和64.3%。最后，使用等值面方法解释了二次流动损失随入射角变化的根本原因。
