真空背压下多截面细径管内气体流动特性分析  

Modelling and Simulation of Gas-Flow via Narrow Tubes with Varied Cross-Sections into Vacuum Chamber

作　　者：任旭东[1] 廖彬[1] 王小刚[1] 曾祥兵[1] 臧立青[1] 张方晓[1] 

机构地区：[1]中国工程物理研究院总体工程研究所,绵阳621900

出　　处：《真空科学与技术学报》2015年第2期161-165,共5页Chinese Journal of Vacuum Science and Technology

摘　　要：采用数值模拟方法研究了真空背压下多截面细径管的气体流动问题,并结合理论和实验结果对管内气体流动特性进行了分析。研究结果表明:在初始时间段,容器压力下降较快,细径管内气体处于流动壅塞状态,壅塞状态稳定后,流速下降缓慢,使得壅塞流动状态可以持续很长时间;壅塞状态下,容器压力随时间呈对数衰减关系,容器压力越小,壅塞状态持续时间越短。同时,壅塞状态下截面突变区域出现了膨胀波和超声速环。随着容器压力的进一步下降,导管入口的流速降低以及导管长度小于临界管长,不足以使气流加速到音速,产生壅塞条件不足,导管Ⅱ内的壅塞状态率先结束,导管Ⅲ和导管Ⅰ内的壅塞现象依次消失。细径管内气体转为层流状态,容器压力下降较慢。数值模拟结果与实验结果吻合较好,为多截面细径管内气体流动特性分析提供依据。The gas flow from its container via narrow tubes with multi-sections into a vacuum chamber was approximated,modeled,analyzed,measured,and simulated with software Fluent.The calculated results show that the gas-flow can be roughly identified as choked-flow and laminar-flow modes.In the initial stage,as the pressure rapidly drops,the gas-flow in the narrow tube is choked;a steady chocked-flow mode lasts for a long time,accompanied with a slow decrease of velocity.In chocked-flow mode,the container＇s pressure decreases exponentially with time;and the lower the pressure,the shorter the chocked-flow time.Besides,the expansion wave and supersonic ring appear in the section-mutation position.When the pressure is low enough and drops more slowly,the chocked-flow mode turns into laminar-flow mode,first in Tube-II,then in Tubes-I and II,possiblly because the low velocity at the inlet fails to be acclerated to speed of sound in a tube shorter than the critical length.The simulated and measured results were found to be in good agreement.

关 键 词：气体流动 多截面细径管 壅塞流 层流 背压 

分 类 号：V416.8[航空宇航科学与技术—航空宇航推进理论与工程]