气体旋转运动对环膜液体射流不稳定性影响的研究(英文)

Study on the Effects of Gas Swirls on Instability of an Annular Viscous Liquid Jet

环膜液体射流的破碎机理研究对于GDI汽油机的雾化过程具有重要的意义。利用线性不稳定性理论研究了旋转气体运动对低阶和高阶模式黏性环膜液体射流破碎的影响。对于色散方程的数值计算结果表明,无论是对称模式还是非对称模式,低阶模式的扰动增长率通常较之高阶模式要大得多,但较之低阶模式扰动,高阶模式对气体旋转运动更为敏感。研究结果同时表明,对于非对称模式,无论是低阶模式还是高阶模式的扰动,气体旋转运动都是液体破碎的失稳因素;对于对称模式,气体旋转运动是低阶模式扰动的促稳因素,然而却是高阶模式扰动的强烈的失稳因素。

The breakup of annular liquid jet is with great importance to the atomization process of GDI engine sprays. A linear temporal instability analysis is made for a viscous annular liquid jet moving in two swirling gas streams with unequal velocities and densities. The dispersion equation is derived, and a round viscous liquid jet in gas stream is investigated to verify the validation of the dispersion equation. The numerical calculating results show that for both disturbances of para-sinuous mode and para-varicose mode, the growth rate of symmetric mode is much larger than that of asymmetric mode, and the effect of gas rotations on the instability of disturbance with asymmetric mode is more sensitive than that with symmetric mode. For the para-sinuous disturbance, the gas rotation plays a positive role on instability both for symmetric and asymmetric mode. However, for the para-varicose disturbance, the gas rotation plays a negative role on instability of symmetric mode, while it plays a strong positive role on instability of asymmetric mode.