基于本征正交分解法的液环泵气液两相流场重构

针对液环泵内复杂的气液两相流动、计算量大且优化设计难以进行的问题,提出了采用本征正交分解法进行液环泵内流场的重构分析。采用泰勒多项式对二维叶片型线进行参数化控制,通过对各控制参数进行适量的扰动得到叶片型线样本集。采用VOF模型进行液环泵内气液两相流场的数值模拟,由叶片型线参数及叶轮内流场数据构建样本的快照集,依照几何相似及网格变形方法插值得到各相似点的流场参数,依据本征正交分解(POD)法将快照集分解为正交基的线性组合。由最小二乘法拟合目标叶型所对应的正交基系数,实现了对目标叶片流场的重构。采用POD方法对2BE-203型液环泵内单个叶轮流道的气液两相流流场进行了重构,精确地重构了单个叶轮内流场结构的各个特征,除在气液交界面附近有一定的误差,整体预测结果具有较高的精度,大大减少了流场预估的计算量。

Reconstruction for Gas-Liquid Flow of Liquid-ring Pump Based on Proper Orthogonal Decomposition

According to the complicated gas-liquid flow in liquid-ring pump, the large amount of calculation, and the difficulty for its optimization design, the flow field reconstitution for the gas-liquid flow of liquid-ring pump based on proper orthogonal decomposition were proposed. The blade was parameterized by Taylor polynomial, and the experiment samples can be designed by introducing small perturbation of the control parameter. The transient gas-liquid flow in liquid ring pump was simulated by using the VOF model. The snapshot set consisted of the control parameter for the blade shape and the flow field data. According to the geometric similarity of the impeller flow passage and the mesh deformation technology, the flow field data of the similar position of each point were interpolated. The snapshot set can be decomposed as linear combination of orthogonal basis by using proper orthogonal decomposition. The coefficients of the objective blade orthogonal basis were fitted by the least square method. The flow field data of the objective blade were reconstructed. In the calculation case for the type of 2BE-203 liquid-ring pump, the gas-liquid flows of single blade passage were reconstructed, and almost all the flow structures were accurately predicted. The prediction had high accuracy except near the gas-liquid interface. The calculation amount for the multiphase flow field was greatly reduced.