初始温度对甲烷-空气爆炸压力影响的试验研究

Experimental Research on Methane-air Mixtures Explosion Pressure under Normal and Elevated Initial Temperatures

借助特殊环境20 L爆炸特性测试系统,研究了初始温度对甲烷-空气爆炸压力的影响,初始压力为0.1 MPa,初始温度变化范围为298～473 K。结果表明,甲烷-空气爆炸的最大爆炸压力随初始温度的升高而降低,初始温度由298 K升高到473 K,最大爆炸压力由0.7833 MPa下降到0.5012 MPa,下降幅度为35.89％。初始温度的升高加快了反应速率,缩短了最大爆炸压力到达时间,由298 K时的127.1 ms缩短到473 K时的85.0 ms。初始温度升高,甲烷-空气最大爆炸压力的上升速率（ dp/dt） max呈上升趋势。当初始温度由298 K上升至473 K时,（ dp/dt） max升幅并不大,仅为9.16％；爆炸特征值KG 不断增大,其爆炸危险性也随之增大。从反应开始到到达最大爆炸压力这段时间内,爆炸压力上升速率的变化在一定程度上可以反映甲烷-空气爆炸反应速率的变化情况。

The influence of initial temperature on the explosion pressure of methane-air mixtures was experimentally investigated at different initial temperature from 298 K to 473 K under the constant initial pressure of 0. 1 MPa. Experi-ments were performed in a closed spherical 20 L vessel with the ignition electrode at the center, which could heat the experimental gas. The results show that the maximum explosion pressure of methane-air mixtures decreases along with the rise of initial temperature. When the initial temperature increases from 298 K to 473 K, the maximum explosion pressure drops from 0. 783 3 MPa to 0. 501 2 MPa, decreased by 35. 89%. Higher initial temperature accelerates the reaction rate, so the reach time of the maximum explosion pressure is shortened from 127. 1 ms at 298 K to 85. 0 ms at 473 K. In the experimental temperature range, the maximum pressure rise rate （ dp/dt） max increases at elevated initial temperature, but the increase is not large, which is only 9. 16%. So the explosion eigen value KG also increases. During the period from the beginning of the reaction to the time reaching the maximum pressure, the rising rate of explosion pressure, to a certain extent, can reflect the change of the methane-air explosion reaction rate.