助推器支承的火箭地面风载荷非定常气动系数(上)

The unsteady aerodynamic coefficient of ground wind load for booster supported launch vehicles

根据新一代运载火箭CZ-5及其动力学相似缩比模型的助推支承、两个弯曲模态主方向的模态参数有显著差别的特点,推导了火箭地面风载荷在模态主方向的非定常气动弯矩系数,给出了非定常气动弯矩的计算方法,并通过坐标转换,得到风轴气动弯矩系数的计算公式。将非定常气动弯矩系数中与动特性有关的参数统称为动态弯矩因子,从而统一了所有类型火箭的地面风载荷非定常气动弯矩系数的计算公式。此外为简化助推器支承火箭地面风载荷的试验方法,给出了气动加速度和位移系数的计算方法,提出了加速度因子和动态位移因子的概念。通过对CZ-5缩比弹性模型的动特性和弯矩因子的计算,分析了支承筒和不同构型模型的影响,并根据各阶弯曲模态对应的不同响应因子的变化,证明了地面风载荷试验只计及一阶模态的合理性。建议采用弯矩和位移测量数据分析非定常气动系数,不宜直接采用加速度数据计算气动系数。

The equations of unsteady aerodynamic bending moment coefficients of asymmetry launch vehicle whose modal parameters in two modal main directions are different, such as CZ-5 launch vehicle, are derived. Through coordinate transforming, the equations of unsteady aerodynamic bending moment coefficients in wind coordinate are derived, in which all of the parameters relating to the structure dynamic characteristic are defined as dynamic bending moment factor. The factors of CZ-5 similar scale model are given in this paper. It is proved that the stiffness of supporting section, the configuration of launch vehicle and model parameters have an effect on the factor. And it is reasonable to use the first modal parameters to analysis the dynamic bending moment factor. In order to improve the processing of measuring launch vehicle ground wind load, aerodynamic acceleration factor using aerodynamic acceleration data and dynamic displacement factor using displacement data are taken forward. The result is that the bending moment data and displacement data can be used to analysis unsteady aerodynamic coefficient directly and acceleration data can＇t.