弹射救生火箭橇气动特性数值模拟及试验验证

Numerical Simulation and Experimental Study on Aerodynamic Characteristics of the Ejection Life-saving Rocket Sled

针对高速运行条件下飞机弹射救生试验难题,全尺寸火箭橇试验是低风险、高费效比的研究手段。为确定气动力对弹射救生火箭橇工作状态的影响,本文建立了全尺寸双轨弹射救生火箭橇模型,在CFX平台上对比分析了k-ε、k-ω和SST这3种湍流模型对数值模拟结果的影响,结果表明湍流模型对计算结果相对误差小于1.5%。基于SST湍流模型,对弹射救生火箭橇橇体和座舱两部分的气动特性进行了数值模拟。结果表明:亚音速和跨音速条件下,弹射救生火箭橇的等效阻力系数随速度的增加而单调递增,橇体和座舱阻力之比随速度增加呈现先减少后增加的规律;火箭橇橇体对弹射救生座舱舱盖的阻力、升力及压强影响均较小,两者计算误差小于16%,火箭橇流场对飞机座舱舱盖切割性能测试影响较小。在亚音速条件下开展了弹射救生火箭橇试验,实验结果与计算值吻合较好,验证了数值模拟方法的可靠性,研究结论可为飞机弹射救生试验提供思路。

The full-scale rocket sled test is a low-risk and cost-effective research method to address the challenges of aircraft ejection life-saving tests under high-speed operating conditions.In order to determine the influence of aerodynamic forces on the working state of the ejection rescue rocket sled,a full-scale dual track ejection rescue rocket sled model was established in this paper.Meanwhile,based on the CFX solver,the impact of three turbulence models(k-ε,k-ω,SST)on the numerical simulation results was compared and analyzed.It shows that the relative errors of drag force and lift force are less than 1.5%.Then the aerodynamic characteristics of the sled body and cockpit of the ejection rescue rocket sled were numerical simulated based on SST turbulence model.The numerical simulation results indicate that the equivalent resistance coefficient of the ejection rescue rocket sled monotonically increases with the increase of velocity,and the ratio of sled body to cabin resistance shows a pattern of first decreasing and then increasing under subsonic and transonic conditions.The impact of rocket sled body on the drag force,lift force and pressure distribution of the ejection rescue cockpit cover is relatively small,with a relative absolute error of less than 16%.Therefore,the flow field of the rocket sled shows insignificant effect on the cutting performance test of the aircraft cockpit cover.Rocket sled tests were conducted for ejection rescue under subsonic conditions.The experimental data are in good agreement with the numerical simulation results,which verifies the reliability of the numerical simulation method.The research conclusion can provide ideas for aircraft ejection life-saving experiments.