دانلود رایگان مقاله بررسی توزیع قطرات در پوشش چتر نجات حلقه بادبان در باران نور

Abstract

As a basal part of the entire study of reliability performance of ringsail parachute and re-entry capsule descending in rain environment, droplets distribution characteristics on canopy surface are investigated firstly via two-phase flow approach in the paper. The model of ringsail parachute and capsule is built on the basis of the sizes of Chinese Shenzhou series spacecraft components. The simulation of droplet trajectories is implemented numerically using the Discrete Phase Model. The numerical simulations considering various rainfall rates and velocities of a ringsail parachute and capsule descending in light rain conditions are conducted. The results show that for one specific rainfall rate, there is a homologous critical value of descending speed of parachute and capsule, which is the dividing line between raindrops being trapped and not being trapped by the canopy; if the descending velocity is less than the critical value, no raindrops will be captured; in raindrops-trapped cases the raindrops are distributed on the bottom skirt zones of the canopy surface and not evenly distributed. The work in the paper will be helpful and significant for the further study of the effects of rain environment on the spacecraft recovery.

5. Conclusions A ringsail parachute and re-entry capsule model descending in a light rain environment is numerically simulated via the twophase flow approach. The droplets distribution characteristics on the canopy surface are researched which belongs to a preliminary stage of the whole research of the reliability performance of  ingsail parachute and capsule descending in rain condition. The simulation results of various cases are presented and analyzed. It is found that for one given rainfall rate, there is a homologous critical value of descending velocity of parachute and capsule, which has a decisive influence on the raindrops being trapped or not being trapped by the canopy; if the descending velocity is less than the critical value, no raindrops will be trapped; in raindropstrapped cases the raindrops are only unevenly distributed on the bottom skirt zones of the canopy surface. However, the experimental results are still needed to directly validate the simulation results in the future when the experiment conditions are ful- filled.