氢气在颗粒床内流动不稳定性分析

Analysis of Hydrogen Gas Flow Instability in a Particle Bed

基于颗粒床反应堆的核热推进技术在深空探测等场景有巨大的优势,氢气在颗粒床内被加热可能会发生流动不稳定现象。理解流动不稳定性发生机理并准确判断不稳定边界对颗粒床反应堆的安全运行有重要的意义。本文对一维颗粒床内的流动过程进行了理论分析,推导了流动稳定性判据和阻力特性指数表达,并得到了流动稳定性边界。采用计算流体力学的方法对颗粒床内的流动换热过程进行了模拟,依据压降–流量特性曲线同样得到了流动稳定性边界,两者预测在趋势上相似,对颗粒床反应堆核热推进系统的设计提供了重要的参考。

Nuclear thermal propulsion technology based on particle bed reactors holds tremendous advantages in scenarios like deep space exploration.However,the heating of hydrogen gas within the particle bed may cause flow instability.Understanding the mechanism behind this flow instability and accurately determining the instability boundaries is crucial for the safe operation of the particle bed reactor.In this study,a theoretical analysis on the flow process within a one-dimensional particle bed is conducted.The criterion for flow stability,an expression of the drag characteristic index,and the flow stability boundaries are derived.Utilizing the computational fluid dynamics method,the heat transfer process within the particle bed is simulated.Additionally,based on the pressure dropflow characteristic curve,flow stability boundaries are derived.Both methods show similar trends in their predictions,providing essential references for the design of particle bed reactor-based nuclear thermal propulsion systems.