摘要
航天领域普遍采用工作压力最高可达45 MPa的高压气瓶作为气源,需要时对外输气。对外输气过程中高压气瓶内的气体均会产生明显的膨胀降温效应,降温的气体会将冷量传递给瓶体,对气瓶的安全性可能产生不利影响。本文针对高压气瓶对外输气过程复杂的传热、传质及热力学多变过程,采用虚拟界面的可变容腔建立一套热力学简化模型,以航天领域常用的氮气、氧气、氦气高压气瓶为研究对象,计算并分析了气瓶对外输气过程中降温效应的影响因素及规律,有效解决了多变过程的微分方程解耦问题,并针对膨胀降温效应对气瓶的安全性可能产生的不利影响提出相应对策。
High-pressure cylinders with working pressure up to 45 MPa are widely used as gas sources in the aerospace field. The gas in cylinder is fed to where the gas is needed. The residual gas inside the cylinder will produce obvious expansion and cooling effect whithout exception during gas feeding. As a result,the cooled gas will transfer the cold capacity to the cylinder and may have negative effects on the safety of cylinder. Aiming at the complex heat,mass transfer and thermodynamic polytropic process of high pressure gas cylinder during gas feeding,a simplified thermodynamic model was established by using variable volume with virtual interface. Taking high-pressure cylinders commonly used in aerospace field filled with nitrogen,oxygen and helium as the research object,the factors affecting the cooling effect and its pattern in the process of gas feeding were calculated and analyzed,the problems of differential equation decoupling of the polytropic process were effectively solved and the corresponding countermeasures were put forward in accordance with the possible adverse effects.
引文
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