Analysis Of The Impact Of Icing On The Parachute Recovery Process

Ices will often accrete on the surface of the flight vehicle when it flies through clouds.The impact of icing on recovery and landing system should be completely analyzed to ensure recovery mission completed well.In this background,this dissertation focuses on the recovery and landing system of the recoverable capsule,studying the influence of icing on the recovery and landing system.The ice accretion on surface of the parachute is simulated with numerical computation and the dynamic model is built to compute the dynamic characteristics.The main researches are as follows:1.According to the methods to compute the flow field of bluffs at home and abroad,the flow field of the parachute is simulated by applying Computational Fluid Dynamics.The one quarter grid and period grid are built for the ringsail parachute.The flow field of the ringsail parachute and the drag coefficient are acquired by Fluent.2.This dissertation analyzes the force on supercooled droplets in flow field.The droplet is regarded as liquid phase distributed in air so that the droplet phase governing equations are built.Two verified cases are applied to prove the model is correct.On the basis of flow field of the ringsail parachute,the droplet phase governing equations are solved to acquire the movement of the droplets and collection efficiency of the ringsail parachute.Droplets of different diameters in different velocities are computed to analyze the effect of droplet diameter and parachute velocity on the collection efficiency of the ringsail parachute.3.According to the analysis of icing process and researches at home and aboard,some improvements for icing model are put forward.The ice accretion on the wing is simulated and compared with the test result.The rime ice on the surface of the ringsail parachute is simulated.Then the mass increment and the change of aerodynamic characteristic are get by simulating the flow field of the icing parachute.4.Basing on the characteristics of the parachute recovery system,a 12-freedom parachute-body model is built.The dynamic parameters of the parachute and capsule are acquired through simulating the recovery and landing process of the capsule in normal condition.Then recovery and landing process of the capsule in icing condition is simulated.The result is compared with the result in normal condition to estimate the influence of ice accretion on the system.The researches provide theory bases for estimating the impact of icing on the parachute recovery and landing process.The computing methods and the dynamic model and the results of flow field and droplet movement can be conducive to the research of the recovery and landing process.