家庭厨房内不同比例混氢天然气泄漏扩散研究

Study on leakage and diffusion of hydrogen-blended natural gas with different ratios in home kitchen

为探究不同比例混氢天然气在家庭厨房内泄漏后的扩散特性,采用FLACS构建家庭厨房数值模型,研究不同比例混氢天然气泄漏后在水平(泄漏口侧到远离泄漏口侧)和垂直方向上的浓度分布,对比自由扩散和对流通风对气体扩散的影响。研究结果表明:距泄漏口上方1.15 m高度以下,高度、时间及混氢比对水平方向上气体体积分数的降幅影响较小;泄漏口侧和远离泄漏口侧垂直方向上具有不同层级的分层现象,且随混氢比和时间的增大,分层现象减弱;混氢比从0%增加到40.0%时,报警时间降幅比仅为1.42%;相较自由扩散,对流通风能快速排出可燃气体,降低风险。研究结果可为城镇燃气混氢应用提供参考。

In order to investigate the diffusion characteristics of hydrogen-blended natural gas with different ratios after leakage in home kitchen,a numerical model of home kitchen was constructed using FLACS.The concentration distribution of hydrogen-blended natural gas with different ratios after leakage in the horizontal(from the side of leakage outlet to the side away from leakage outlet)and vertical directions was studied,and the influence of free diffusion and convective ventilation on the gas diffusion was compared.The results show that below the height of 1.15 m above the leakage outlet,the influence of height,time and hydrogen-blended ratio on the decrease of gas volume fraction in the horizontal direction is small.There are the stratification phenomena of different layers in the vertical direction on the side of leakage outlet and the side away from the leakage outlet,and the stratification phenomenon is weakened with the increase of the hydrogen-blended ratio and time.When the hydrogen-blended ratio increases from 0%to 40.0%,the reduction ratio of the alarm time is only 1.42%.Compared with free diffusion,the convective ventilation can quickly discharge the combustible gases and reduce the risk.The results of the study can provide a reference for the application of hydrogen mixing in urban gas.