富氧条件下不同泄爆面积对CH4燃烧诱导快速相变的影响

为了研究富氧条件下不同泄爆面积对CH4燃烧诱导快速相变的影响,基于自主设计搭建的CH4燃烧诱导快速相变试验台,通过改变富氧系数和泄爆面积对CH4燃烧的压力振荡特性进行研究,分析了不同富氧系数E(0.21,0.3,0.4,0.6)及泄爆面积比(0,0.25,0.5,0.75,1)下CH4燃烧的压力峰值、到达压力峰值的时间及特征时间等参数的变化趋势。结果表明,随富氧系数增大,爆炸压力峰值逐渐增大。富氧系数E=0.21时,压力峰值低于相应的绝热压力,无压力振荡;当E=0.3时,压力峰值低于相应的绝热压力且伴随压力振荡。当E为0.4、0.6时,压力峰值高于相应绝热压力且伴随压力振荡;在泄爆条件下,随富氧系数增加,到达压力峰值的时间逐渐减小。通过分析不锈钢管道中的燃烧诱导快速相变现象,发现泄爆可以有效降低爆炸压力峰值,且随泄爆面积比增大,到达压力峰值的时间提前。

Impact of the different venting areas on the combustion induced rapid phase transition(CRPT)by CH4/N2/O2-en-riched mixture

In order to examine and trace the effect of the different explosion areas on the CH4 combustion-induced quick phase transition under the oxygen-enriched condition,the given paper takes it as its topic to trace and examine the oscillation features of CH4 combustion pressure based on the self-laid test bed by changing the oxygen-rich coefficient and the blasting area. And,then,we have made detailed analyses of the parameters of the pressure peak,the time needed to reach the pressure peak,and the particularly needed time for the CH4 combustion under the different oxygen enrichment coefficients known as E(0. 21,0. 3,0. 4,0. 6) and the explosion area ratios(0,0. 25,0. 5,0. 75,1). The results of our examination show that,with the increase of the oxygen-enriched coefficient,the peak value of the explosion pressure tends to increase gradually,with θ1= 2 being a significant symbol to judge the fast phase transition induced by the combustion. This may tend to show that such a phenomenon ought to be the coupling effect of the physical explosion and the chemical explosion,whose intensity tends to increase with the increase of θ2. When E = 0. 21,the pressure peak tends to be lower than the corresponding adiabatic pressure,though there may not experience any pressure oscillation. However,when E =0. 3,the pressure peak would become lower than the corresponding adiabatic pressure accompanied by the pressure oscillation.What is more,when E = 0. 4 or 0. 6,the pressure peak tends to become greater than the corresponding adiabatic pressure along with the pressure oscillations. Thus,it can be found that the high-frequency pressure oscillation does not necessarily reach the pressure peaks for the adiabatic pressure. Rather,the time to reach the pressure peak gradually nay tend to decrease with the increase of the oxygen-enriched coefficient under the condition of the explosion-proof. The actual situation should be like this: The greater the oxygen-enriched coefficient,the more obvious such a trend of change. And,therefore,by analyzing the phenomenon of the quick phase transition induced by the combustion in the stainless steel pipelines,the explosion pressure can help to reduce the peak pressure of explosion effectively. And,in turn,the pressure oscillation may also tend to be more and more obvious with the increase of the ratio of the explosion area to the peak pressure.