旋转冲压增程弹进气道内流场旋流数计算

为了研究高速旋转对冲压增程弹进气道的影响,对零攻角下旋转弹丸进气道入口与出口旋流数进行了理论推导,得到了旋流数的解析计算式。为了检验理论分析各项假设的合理性,并对旋流数解析式的误差进行分析,使用数值模拟的方法对某双锥进气道的流场进行了计算。分析发现,冲压弹丸进气道前方来流旋流数很小,因此旋转对进气流量影响很小;理论解析式计算所得进气道出口旋流数比数值计算结果偏大,且背压越低偏差越大;普通旋转冲压弹丸进气道出口旋流数低于0.2,由于在此弱旋流进气条件下,固体燃料冲压发动机工作状态与直流进气状态接近,因此弹丸的旋转对冲压发动机工作影响较小。

Swirl number calculation in the inlet of spinning ramjet assisted range projectile

In order to study the high-speed spinning effect on the ramjet assisted range projectile,the swirl number in the inlet was theoretically analyzed at the condition of zero angle of attack.The analytical formula of swirl number was obtained.In order to test the rationality of the hypothesis and analyze the error of the analytical formula,the flow field of an axisymmetric double cone-shaped inlet was numerically simulated.It was concluded that the swirl number at the front of the inlet was very small,the air mass flow rate was nearly the same as the condition of no spinning.The swirl number at the outlet of the inlet calculated with the analytical formula was always larger than that of numerical simulation,and the error of the analytical formula increased with decreasing the back pressure.The swirl number at the outlet of the spinning ramjet assisted range projectile inlet was usually smaller than 0.2 and the flow field in the solid fuel ramjet was weak swirl flow.Thus,the spinning has little effect on the ramjet.