导电流体中气泡径向振动行为的磁场控制

Magnetic field control on radial oscillation behavior of a gas bubble in conductive fluid

液态金属中气泡行为是磁流体力学的重要方面。为对磁场条件下导电流体中气泡动力学行为作全面理解,基于磁流体动力学方法建立了磁场条件下导电流体中气泡径向振动的无量纲化动力学方程,数值研究了磁场对导电流体中气泡径向非线性振动稳定性、泡内温度、泡内气压及液体空化阈值的影响。结果显示：磁场增强了气泡非线性振动的稳定性,随着磁场增强且当作用在泡上的电磁力与惯性力数量级可比时,气泡运动为稳定的周期性振动;同时,磁场引起泡内温度、泡内压力及液体空化阈值变化。研究表明,可用磁场调节和控制液态金属中气泡的运动使其满足工程应用需求。

The behavior of bubbles in liquid metal is an important aspect of the magnetohydrodynamic. To fully investigate the effects of an uniform magnetic field on a growing or collapsing bubble, based on magnetic hydrodynamics, it is established a modified dimensionless dynamic equation of a radial vibrating gas bubble immersed in a conductive fluid and driven by a sine sound field and exposed to an uniform external magnetic field. The effects of magnetic field on the stability of bubbles nonlinearly oscillating, the temperature and pressure inside the bubble, and fluid cavitation threshold are studied numerically. The numerical results have shown that magnetic field enhances the stability of bubbles nonlinearly vibrating, especially when the magnitude of the electromagnetic force is comparable to the inertial force acting on the bubble interface, it transforms the irregular pulsation of the bubble into a stable regular oscillation; at the same time, the magnetic field causes that the temperature, pressure inside the bubble and liquid cavitation threshold change. It is showed that the magnetic field can be used to regulate and control the movement of the gas bubbles to meet the engineering application requirements.