在实验室小型模拟巷道的方形管道内,采用自制的微细热电偶和离子电流传感器、压电式压力传感器,测试了有/无障碍物2种情况下在不同位置处浓度为10.17%甲烷空气预混火焰锋面的传播过程中温度、离子电流强度及压力变化情况。实验结果表明,障碍物存在导致火焰锋面的最高温度值略有降低,由靠近点火端位置的1 303.7℃下降到1 234.4℃,远离点火端位置的1 198.7℃下降到902.5℃;离子电流曲线出现了明显的双峰值,强度明显增大,由靠近点火端的146.25nA上升到160nA,远离点火端的432.5nA上升到605nA;火焰锋面前方过早的产生前驱压力波,加速燃烧转爆轰(DDT)过程的提前实现。因此,巷道内应避免障碍物的存在。
The temperature,ion current,overpressure and photoelectric signal of flame front at the same cross-section in square tube of laboratory simulation of tunnel are recorded by homemade thermocouple,homemade ion probe,pressure transducer and photoelectrical transducer at the same time.The parameters' changes of flame front with the same gas concentration of 10.17% are compared with obstacles or without obstacles.The results show that,when the obstacles exists,the value of temperature is slightly lower,the temperature is from 1 303.7 ℃ down to 1 234.4 ℃ by close to ignition position and from 1 198.7 ℃ down to 902.5 ℃ away from ignition position.The value of ion current is slightly higher and the double peak values occur obviously in the signals of ion current,the peak value of ion current is from 1 46.25 nA up to 160 nA in the vicinity and from 432.5 nA up to 605 nA in the distance.The precursor compression wave in flame propagation tube is appeared ahead to further promote the gas explosion process in DDT.Therefore,roadway should minimize the presence of obstacles.