考虑螺旋桨滑流的机载探空仪分离安全性研究

Safety research on release of airborne dropsonde with propeller slipstream effects considered

为研究螺旋桨滑流效应下机载探空仪投放过程中气动干扰特性及探空仪运动规律,采用计算流体力学(CFD)方法对机载探空仪投放过程进行非定常数值模拟。通过动态嵌套网格技术模拟螺旋桨转动和探空仪运动,结合刚体六自由度运动方程求解三维非定常N-S(Navier-Stokes)方程,成功模拟了基于察/打一体无人机平台的探空仪自由投放过程,获得了包括探空仪运动姿态、运动轨迹等在内的数据信息。计算结果表明:探空仪初始弹射速度越大,其脱离螺旋桨危险区域的时间越短,对飞行越安全;螺旋桨滑流对机体方向气流有明显的加速效应,使探空仪更快脱离螺旋桨区域;三个常用的巡航飞行迎角对比发现,0°迎角下投放最优,2°迎角次之,-2°迎角不满足投放安全性要求。

In order to study the aerodynamic interference and movement rules of external store with propeller slipstream effects, computational fluid dynamics(CFD) method was used to calculate the release process of airborne dropsonde. A dynamic chimera grid approach is used to simulate the propeller rotation and dropsonde motion. CFD integrated with the 6-DOF movement equation and the three-dimensional unsteady N-S equation, simulates the free launch of the R/S UAV(Reconnaissance and Strike UAV system) dropsonde, including the movement attitude and trajectory. The results show that, the greater the initial ejection velocity of dropsonde, the shorter the time it takes to escape from the propeller danger zone, which is safer for flight. The propeller slipstream has obvious acceleration effect on the air flow in the direction of the fuselage, forcing the dropsonde out of the propeller zone faster. Comparing the three commonly used cruise flight angles of attack, 0° is best, followed by 2°,-2°does not meet the safety requirements.