低压差驱动下中等半径比内轴高旋圆柱间轴流量的数值计算

利用RSM湍流模型/标准壁面函数对低压差驱动下中等半径比内轴高旋圆柱间流场进行了数值模拟。圆柱的内半径为4.45 cm,外半径为5.25 cm,半径比为0.848,轴间距为0.8 cm,形状比分别为5,10,15,20,泰勒数比分别为500,625,750,875,1 000。模拟结果表明,RSM湍流模型/标准壁面函数对低压差驱动下中等半径比内轴高旋圆柱间流场有较强的预报能力。随着压差的增加,轴流量随之增加,随着压差的进一步增加,压力流的作用处于主导地位,压力流的增强最终导致涡胞消失,轴间流场特征主要表现为压力流。随着旋转速度的增加,内壁高旋产生的旋转效应增强,轴向压差对轴间流场的作用相对减弱,导致轴流量减少。随着形状比的增加,轴流量呈现逐步减小的趋势,而且随着形状比的进一步增加,轴流量减少的趋势变缓。

Numerical Simulation of Axial Flow between Cylinders with Rotating Inner Cylinder Driven by Low Pressure Difference

Numerical simulation was made to study the axial flow between the rotating cylinders driven by low pressure difference.The radius of inner and outer cylinder is 4.45 cm and 5.25 cm respectively,the radius ratio is 0.848,aspect ratio is between 5 and 20,Taylor number ratio is between 500 and 1 000.The inner cylinder is rotating and the outer is stationary.The results of the simulation show that RSM model with standard law of wall has great ability of simulating the axial flow between cylinders driven by low pressure difference.With the increase of the pressure difference,axial flux increases,and when the pressure difference increases further,the pressure flow is prominent,and higher pressure difference leads to the disappearance of the vortexes,the flow between the cylinders is mainly characterized by pressure flow.With the increase of the rotating speed,the effection of the rotating of the inner cylinder become stronger,the effection of axial pressure difference on axial flow becomes weaker relatively,and therefore axial flux decreases.With the increase of the aspect ratio,the axial flux decreases,and when the aspect ratio increases further,the decrease speed of the axial flux becomes smaller.