球头体逆向喷流减阻的数值模拟研究

NUMERICAL INVESTIGATION ON COUNTER-FLOW JET DRAG REDUCTION OF A SPHERICAL BODY

为研究逆向喷流对超声速球头体减阻的影响,该文结合标准k-ε湍流模型,通过求解轴对称和三维Navier-Stokes方程,数值模拟了超声速球头体逆向冷喷流流场,着重分析了喷口总压、喷口尺寸及攻角对流场模态和减阻效果的影响。计算结果显示:喷流能使球头体受到的阻力明显减小;随着喷流总压的增大,在不同喷口尺寸和攻角下,流场均先后经历长射流和短射流穿透模态;存在最大减阻临界喷流总压值,该值与喷口尺寸比呈近似的线性关系,在所研究参数范围内最大减阻可达54.7%;随着攻角的增大,流场的不对称性加强,减阻效果下降。该文的研究对超声速钝体减阻技术在工程上的应用具有一定的参考价值。

The flow field of a supersonic flow over a spherical body mixed with a counter-flow jet from the front stagnation point of the body is numerically studied by solving the asymmetric and three dimensional Navier-Stokes equations coupled with the standard κ-ε turbulence model using the Van Leer＇s flux vector splitting spatial discretion scheme. The effect of jet total pressure, jet exit size and the angle of attack on drag reduction of the body is systematically investigated. It is found that the flow field experiences a long penetration mode and a short penetration mode in sequence with the increasing of the jet total pressure when the jet exit size and angle of attack are fixed and there is a critical value of jet total pressure where an optimal drag reduction can be obtained. This critical value varies with the jet exit size ratio linearly. The results show that the maximum drag reduction can reach as high as 54.7% for the cases studied. With the increasing of the angle of attack, the asymmetry of flow field is enhanced and the drag reduction efficiency is reduced. The present results provide useful information on drag reduction technology of a supersonic blunt body in engineering applications.