轴向通流旋转盘腔内流动不稳定性研究

为了研究旋转腔内流动不稳定性问题,采用旋转坐标系稳态方程,用数值模拟的方法分析了轴向通流旋转盘腔内的流动,得到了旋转系下哥氏力和离心浮升力分别对流动不稳定的作用,以及这两个力的非线性综合作用对流动不稳定的影响.结果表明:哥氏力是恢复力,不影响流动稳定性;离心浮升力是造成流动不稳定的主要因素,盘腔内的流动是离心力场下的Rayleigh-Benard对流和强迫对流的混合流,随着浮升力的增强流动由稳态发展为非稳态;哥氏力与离心浮升力的综合作用加剧了流动不稳定性,盘腔内r-θ面出现了明显的旋向相反的对涡.

Investigation of flow instability in rotating cavity with axial throughflow of cooling air

To investigate the instability of flow in rotating cavities, the flow in a heated rotating cavity with cool air axial throughflow was numerically studied, based on the time-independent incompressible equations in rotating system, and low Reynolds K-ε turbulent model. The flows in the cavity, affected either by the Coriolis force, by the centrifugal-buoyancy force, or by both of these two forces were calculated. The results show that the Coriolis force acting as a resilience force does not lead to flow vibrating; the centrifugal-buoyancy force is the key factor causing flow instable, the Rayleigh_Benard convection flow induced by the centrifugal-buoyancy force is blended with the forced convection flow in the cavity, and it develops from stable to unstable as buoyancy force increases. With the coaction of these two forces the flow instability is enhanced, cyclonic and anti-cyclonic circulations can be observed circumferentially.