两级入轨(two stage to orbit,TSTO)飞行器在高超声速来流条件下级间分离,会在两级之间产生复杂的非定常气动干扰,直接增加TSTO级间分离失败风险.级间分离过程中的这种复杂气动干扰伴随着两级之间的激波与边界层干扰、马蹄涡、激波与尾...两级入轨(two stage to orbit,TSTO)飞行器在高超声速来流条件下级间分离,会在两级之间产生复杂的非定常气动干扰,直接增加TSTO级间分离失败风险.级间分离过程中的这种复杂气动干扰伴随着两级之间的激波与边界层干扰、马蹄涡、激波与尾流干扰的综合作用.本文将TSTO助推级和轨道级的复杂模型简化为两个三维楔,采用重叠动网格技术,耦合求解流动控制方程及六自由度刚体动力学方程组对级间分离过程开展模拟分析,探究级间分离流动特性及其物理机制.在数值分析过程中,针对不同抬升角度下的TSTO三维流场进行了静态和动态数值模拟,给出了不同抬升角度下的干扰流场流动规律和特性,结合流场结构和壁面压力分布以及分离流动模式阐明了两级之间这种气动干扰对TSTO气动分离的影响机制,并探讨了轨道级抬升角对TSTO安全分离的影响.结果表明两级间的气动干扰强度随着轨道级抬升角的增大而增强,并且在动态分离过程中随着两级间隙的增加而减弱;在轨道级释放前两级间气动干扰和三维分离拓扑结构随着抬升角的增大变得更加复杂,流动分离区域增大,临界点数量增加;在级间分离过程中,两级气动特性变化幅度随着轨道级抬升角增大而增大,分离时间则随之减小.另外,当轨道级抬升角度在6°~8°时可实现该TSTO更加安全可靠的分离.展开更多
This paper deals with the problem of the instability regions of a free-free flexible jointed bipartite beam under the follower and transversal forces as a realistic simulation of a two-stage aerospace structure. The a...This paper deals with the problem of the instability regions of a free-free flexible jointed bipartite beam under the follower and transversal forces as a realistic simulation of a two-stage aerospace structure. The aim of this study is to analyze the effects of the characteristics of a flexible joint on the beam instability to use maximum bearable propulsion force. A parametric study is conducted to investigate the effects of the stiffness and the location of the joint on the critical follower force by the Ritz method and the Newmark method, then to research the vibrational properties of the structure. It has been shown that the nature of instability is quite unpredictable and dependent on the stiffness and the location of the joint. The increase of the follower force or the transversal force will increase the vibration of the model and consequently cause a destructive phenomenon in the control system of the aerospace structure. Furthermore, this paper introduces a new concept of the parametric approach to analyze the characteristics effects of a flexible two-stage aerospace structure joint design.展开更多
文摘两级入轨(two stage to orbit,TSTO)飞行器在高超声速来流条件下级间分离,会在两级之间产生复杂的非定常气动干扰,直接增加TSTO级间分离失败风险.级间分离过程中的这种复杂气动干扰伴随着两级之间的激波与边界层干扰、马蹄涡、激波与尾流干扰的综合作用.本文将TSTO助推级和轨道级的复杂模型简化为两个三维楔,采用重叠动网格技术,耦合求解流动控制方程及六自由度刚体动力学方程组对级间分离过程开展模拟分析,探究级间分离流动特性及其物理机制.在数值分析过程中,针对不同抬升角度下的TSTO三维流场进行了静态和动态数值模拟,给出了不同抬升角度下的干扰流场流动规律和特性,结合流场结构和壁面压力分布以及分离流动模式阐明了两级之间这种气动干扰对TSTO气动分离的影响机制,并探讨了轨道级抬升角对TSTO安全分离的影响.结果表明两级间的气动干扰强度随着轨道级抬升角的增大而增强,并且在动态分离过程中随着两级间隙的增加而减弱;在轨道级释放前两级间气动干扰和三维分离拓扑结构随着抬升角的增大变得更加复杂,流动分离区域增大,临界点数量增加;在级间分离过程中,两级气动特性变化幅度随着轨道级抬升角增大而增大,分离时间则随之减小.另外,当轨道级抬升角度在6°~8°时可实现该TSTO更加安全可靠的分离.
文摘This paper deals with the problem of the instability regions of a free-free flexible jointed bipartite beam under the follower and transversal forces as a realistic simulation of a two-stage aerospace structure. The aim of this study is to analyze the effects of the characteristics of a flexible joint on the beam instability to use maximum bearable propulsion force. A parametric study is conducted to investigate the effects of the stiffness and the location of the joint on the critical follower force by the Ritz method and the Newmark method, then to research the vibrational properties of the structure. It has been shown that the nature of instability is quite unpredictable and dependent on the stiffness and the location of the joint. The increase of the follower force or the transversal force will increase the vibration of the model and consequently cause a destructive phenomenon in the control system of the aerospace structure. Furthermore, this paper introduces a new concept of the parametric approach to analyze the characteristics effects of a flexible two-stage aerospace structure joint design.
