小天体的多种尺寸颗粒样品收集容器流域的数值模拟

采集小天体表面的样品并返回是当前小天体探测的核心目标之一，样品容器流域设计是氮气激励采样技术的关键.为了保证样品容器具备高效的收集性能，要求样品容器的流域设计能够对样品颗粒形成陷阱效应，并对样品颗粒进行有效的分级.旋风式样品收集容器方案利用旋风离心力和引导叶片的共同作用对样品颗粒进行收集和分级.为了验证这种方案在微重力环境下的性能和可行性，本文利用Fluent软件进行了流域的数值模拟.模拟结果表明:在确定容器的结构下，样品容器的最优氮气入口速度为0.6 m·s-1，容器在该速度下的样品收集效率达到99.7%.样品容器的流域具备很好的颗粒分级功能，对小于2mm的样品颗粒的捕获率超过了90%，其压力损失也在合理的范围之内.本文研究结果可为小天体采样任务提供借鉴. 

Numerical Investigation on Collector of Asteroid's Particles with Various Sizes

Collecting and returning samples from the asteroid's surface is one of the significant targets of the current asteroid detection. The key issue of the nitrogen purge sampling technology is the flow field design of the sample container. In order to ensure that the sample container has an efficient collection performance, the flow field design of the sample container must solve two key problems, one problem is the flow field how to form a trap effect on the sample particles, and another problem is the flow field how to effectively classify the sample particles. Therefore, the researchers proposed a scheme of the sample container, which uses the combined effect of centrifugal force and guide blade to collect and classify the sample particles. For verifying the performance and feasibility of this scheme in a microgravity environment, the researchers carried out the numerical simulation with Fluent software. Under the boundary conditions of the container, the simulation program calculated the velocity of nitrogen at the inlet, and the optimal value is 0.6 m·s-1, the efficiency of the container at this velocity reaches 99.7%, the flow field of the sample container also has a good particle classification function, and its capture rate of particles that less than 2mm exceeds 90%. Its pressure loss is also within a reasonable range, the research results of this paper can provide a reference for the upcoming asteroid's sampling task in China.