Study On The Flight Characteristics Of Parawing At The Last Stage Of Recycling

The launch load quality and launch times of spacecraft are increased,the cost of per kilogram is very expensive to launch spacecraft,and most of the spacecraft can only be used once and cannot be recycled again,so the aerospace activities expend extremely large,which undoubtedly limits its development and application greatly.If the spacecraft can be low-cost recycling and reuse,it will promote and improve the development of space industry.This paper analyzes the application of single-layer parawing to the return process of spacecraft,to study its basic aerodynamic performance as a low wing load lift pneumatic reducer,and the numerical simulation of stable flight characteristics and flared landing process is carried out.Firstly,the basic aerodynamic characteristics of the parawing are simulated by infinite load mass,and the basic aerodynamic parameters of the relevant airfoil are obtained.The law of the lift coefficient and the lift-drag ratio with the angle of attack in the laminar and turbulence model are analyzed and compared.For a parawing,the changed trend of the lift coefficient in the different air models are the same,and the numerical value is almost the same.Under the same angle of attack,the lift-drag ratio calculated by the laminar flow model is larger than the turbulence model.In the same air model,the parawing is flatter,the lift-drag ratio is larger.Then,the flight simulation of the parawing is carried out,and the stable flight characteristics of the parawing are studied.Using LS-DYNA can simulate the actual environment accurately.It is different from the multi-degree of freedom analysis method,and it can use a reasonable parameter setting to simulate the actual airdrop process.There is a certain difference between the simulation analysis of the stable flight of the finite load parawing and the simulated by infinite load mass.Finally,numerical simulation for the flared landing characteristics of parawing was carried out,and the operation method is proved.By changing the parawing's wing type,the process of flared landing simulation is carried out and the three different operation methods are compared.The basic law of flared landing is obtained: the operation time is longer and the velocity of horizontal direction for the parawing is slower,but the minimum sinking speed of the load will be larger;drop angle is larger,the load sinking speed is smaller.Although it is not possible to obtain the minimum speed in both directions of forward and sinking at the same time,a smaller sinking velocity of the load can be obtained by appropriately adjusting the pull-down time and the pull-down amount.