高压氢气小孔泄漏射流分层流动模型与验证

Validation of flow partitioning model for high pressure hydrogen jets through small orifices

高压氢气泄漏射流是氢安全研究的重要内容,而在一定实验测量的基础上进行数值模拟是该领域的重要研究手段。目前高压氢气射流完整数值模拟存在计算效率低、不稳定和难收敛的问题,而现有的简化模拟方法存在模型假设不合理和计算结果不准确的问题。本文在定量激波结构测量的基础上,结合气体状态方程和守恒方程构建了分层流动模型,综合考虑了实际的射流核心区和边界层内不同的流动情况,且无需计算气流参数变化剧烈的激波区,从而简化了数值模拟计算。采用分层流动模型模拟的速度场和浓度场计算结果与完整模拟的计算值和实验测量值一致,优于采用传统虚喷管模型模拟的结果。该研究为高压氢气泄漏研究提供了一种在保证计算结果准确性基础上提高计算效率的模拟方法,对进一步推动氢安全研究具有一定意义。

High pressure hydrogen jets are a critical topic in hydrogen safety research.Numerical simulations validated by measurements are an essential way to study high pressure hydrogen jets.However,the complete modeling of high pressure hydrogen jets is inefficient,unstable and difficult to converge,while the existing simplified models are based on non-physical assumptions and result in inaccurate predictions. A flow partitioning model based on quantitative shock structure measurements was developed by combining a real gas equation of state with the flow and energy conservation equations.The flow partitioning model takes into account the different flow conditions in the core flow region and the mixing layer and avoids modeling the shock region where the gas state varies dramatically which significantly simplifies the calculation.The predicted velocity and concentration distributions using the flow partitioning model agree well with the predictions by the complete model and with measurements,with these predictions being superior to predictions using the canonical notional nozzle model.The present study provides a reduced order modeling approach that simplifies the simulations without sacrificing the accuracy which will benefit hydrogen safety research.