【作者】 张伟； 张瑞平； 陈建业； 熊炜； 张小斌； 邱利民；

【Author】 ZHANG Wei,ZhANG Rui-ping CHEN Jian-ye,XIONG Wei,ZHANG Xiao-bin,QIU Li-min Institute of Refrigeration and Cryogenics,Zhejiang University,Hangzhou,310027,China

【机构】 浙江大学制冷与低温研究所；

【摘要】 非稳态云状空化过程对水力机械的性能,如流量,升力,推力和扭矩,有着重大影响。基于动态空化模型数值研究了绕三维扭曲翼型(Twist-11N)的非定常流动。相对于传统空化模型,动态空化模型考虑了压力变化对半径的影响;同时对RNGκ-ε模型进行了修正以避免出现过大的湍流黏度。分析了翼型表面不同位置非稳态压力变化,计算所得的压力分布和周期与常用的完全空化模型吻合良好;得到了空化非稳态脱离表面过程,发现三维空化流动呈现出不同于二维的特征,空泡脱落是翼型弦长方向回射流和展向方向侧面射流两者共同作用的结果,脱落结构也因此先后呈现出主体脱落和二次脱落两种形式。研究结果验证了动态空化模型用于三维非稳态空化的可靠性和准确性。更多还原

【Abstract】 Periodically unsteady shedding of partial cavity has a great effect on performance of hydraulic machines.This paper investigates the unsteady partial cavitating flow over a three-dimensional twisted hydrofoil(Twist-11N) based on the dynamic cavitation model(DCM).Compared the conventional cavitation models,such as Full Cavitation Model(FCM),DCM considers pressure-dependent bubble radius during the cavitating process.The RNG k-εmodel is modified to avoid excessive turbulent viscosity.The dynamic pressure changes at different positions on the hydrofoil surface are presented and compared with the results from FCM,and they are well accordant.It is revealed that the shedding mechanism of 3D hydrofoil is different from that of 2D one;the former is primarily due to the interaction of re-entrant jet flow and side-entrant jet flow instead of the single re-entrant jet flow in the 2D case.As a result,there appears primary shedding and secondary one in sequence.The computations validate the DCM for modeling the 3D unsteady cavitating flow.更多还原