开敞空间掺氢天然气爆燃特性影响因素研究

Study on influencing factors of deflagration characteristics of hydrogen-blended natural gas in open space

为加深对开放空间内低掺氢比天然气爆燃特性的了解,在当量比1.1条件下,对不同掺氢比下掺氢甲烷混合气进行试验研究,分析掺氢比例、湍流扰动对火焰形态、火焰传播速度和爆燃超压的影响。研究结果表明:掺氢比例对反应有单向促进作用,随着掺氢比例的提高,掺氢天然气的火焰形态变化明显,火焰传播速度增大,爆燃超压峰值加速上升,爆燃冲击波传播能力增强;初始湍流则对反应起到促进和抑制的双向作用;开放空间掺氢天然气爆燃超压峰值与最大火焰速度存在的正比例线型关系,可借助拟合公式通过最大火焰速度估算爆燃超压峰值。研究结果可为低掺氢比掺氢天然气管线落地应用提供理论支撑。

In order to deepen the understanding on the deflagration characteristics of natural gas with low hydrogen blending ratio in open space,the experiments were carried out on the mixture of methane and hydrogen with different hydrogen blending ratios when the equivalence ratio was 1.1,and the influence of hydrogen blending ratio and turbulence disturbance on the flame morphology,flame propagation speed,and deflagration overpressure was analyzed.The results show that the hydrogen blending ratio has a unidirectional promotion effect on the reaction,and with the increase of hydrogen blending ratio,the flame morphology of hydrogen-blended natural gas changes significantly,the flame propagation speed increases,the peak deflagration overpressure accelerates,and the propagation ability of deflagration shock wave is enhanced;The initial turbulence plays a bi-directional role in promoting and inhibiting the reaction.The peak deflagration overpressure of hydrogen-blended natural gas in open space has a positive proportional linear relationship with the maximum flame speed,and the peak deflagration overpressure can be estimated from the maximum flame speed with the help of the fitting formula.The research results can provide theoretical support for the application of hydrogen-blended natural gas pipelines with low hydrogen blending ratio.