受限空间内天然气爆炸反应过程模拟分析

为定量研究受限空间内天然气爆炸反应动力学特征，开展了3个方面的研究工作，①建立了基于激波管的天然气爆炸过程数值分析模型；②将天然气气相燃烧动力学反应分解为53种反应组分、325种基元反应，给出了朗金―雨贡尼关系式和正激波的压强比、密度比和温度比计算方法；③利用化学反应模拟软件CHEMKIN构建天然气燃烧过程机理文件，对激波诱导受限空间内天然气混气爆炸过程进行数值模拟，讨论了反应过程、初始压力和空间尺寸对天然气爆炸过程的影响，并绘制了天然气爆炸温度、压力变化特征曲线。结果表明：采用入射激波模拟混气引爆过程中体系温度会出现跳跃式上升随之向下扰动；混气被引爆后温度逐步提高，在温度达到峰值时压力随之提高；提高初始压力将缩短混气引爆时间，高的初始压力可以得到更为迅速的反应速度和更高的爆炸压力；空间尺寸对散热作用的影响高于其对活性基团消毁作用的影响，小尺寸空间条件下可以获得更迅速的爆炸升压速度。

Simulation analysis of natural gas explosion within confined space

To quantify the kinetics features of natural gas explosion in a confined space, researches were conducted on three aspects. Firstly, a numerical model based on shock wave tubes was established to analyze the process of natural gas explosion. Secondly, kinetic reactions for the combustion of natural gas were divided into 53 reaction components and 325 types of elementary reaction, and the Rankine-Hugoniot Equation, together with methods for the calculation of pressure, density and temperature ratios of normal shocks, were proposed. Thirdly, gas combustion mechanisms were determined by using the chemical reaction simulation software CHEMKIN-PRO to perform numerical simulation of natural gas mixture explosion induced by shock waves in a confined space. Moreover, impacts of reaction process, initial pressure and spatial dimensions on natural gas explosion were reviewed, and characteristic curves for changes in temperatures and pressures during natural gas explosions were generated. Research results show that the system temperatures in the explosion of natural gas mixtures induced by feeding shock waves may increase in leap accompanied by downward disturbances. Upon detonation, temperatures of gas mixtures may increase gradually. Pressures may also increase as soon as the peak temperature is reached. Increases in initial pressures may shorten the detonation time of gas mixtures. In addition, higher initial pressures may generate higher reaction speeds and explosion pressures. With cooling effects of internal walls of the shock wave tubes stronger than the destruction of active groups due to collisions, minor spatial dimensions may generate higher speeds in pressure boosting induced by such explosions.