Research And Application Of Some Dynamic Problems Of The Recovery System Of Manned Spacecraft

Several dynamic problems relative with safe reliability of parachute recovery system of manned spacecraft are studied in this work. These problems consist of calculation of parachute inflation performance, modeling of parachute-payload multi-body system, modeling of parachute suspension system, modeling of fluid-structure interaction for parachute inflation, computation of flow around bluff bodies, and analysis of wake re-contact phenomenon.The dynamic model of parachute-payload system during the inflation process is developed by combining equations of motion for parachute-payload system with equations represented the shape change of parachute canopy. With the application of the model, the dynamic property of parachute-payload system during the inflation process can be analyzed in detail. Based On the work of Potvin, Sundberg, and Purvis, the initial inflation model and the final inflation model are derived independently. Fluid-structure interaction and the suppleness property of parachute system are taken into account in these models, so the aerodynamic force and the fabric tension in different parts of the parachute can be calculated. In order to perfect the fluid-structure interaction model for parachute inflation, the pressure on the canopy is calculated by using viscous vortex method through hard programming work. In the work, some key computational techniques are accomplished, such as discretization of solid body surface, calculation of vorticity on the body surface, vortex shedding, vortex particle splitting and merging, fast multi-pole method. These techniques elementarily resolve the computation problem of flow around the parachute canopy, and provide a base for developing more perfect fluid-structure interaction model for parachute inflation. Based on Oler's work, the dynamic model of the wake re-contact for parachute-payload system is developed. A novel modeling method for parachute suspension system is developed. Compared with former methods, it is more universal and can be used to get the status of the suspension cable without complicated logic. The method has been used successfully in the simulation software of spacecraft recovery system.The research completed in this work provides theory basis for dynamic analysis of Shenzhou manned spacecraft recovery system. With the application of the models in this work to Shenzhou recovery system, the dynamic properties of parachutes and capsule have been achieved, and some results provide references for evaluating the performance of the system.