甲苯、正癸烷点火延迟的激波管实验研究

利用反射型激波管、压力传感器、光电倍增管、示波器等组成的测试系统,通过测量激波压力信号和OH自由基光强信号,在1175~2023 K,压力为0.1 MPa,当量比为0.5、1.0、2.0的条件下,获得了甲苯/氧气/氮气、正癸烷/氧气/氮气的点火延迟时间。在实验中利用超声速气流雾化液态燃料,制备了均匀的燃料气溶胶。通过控制反射激波缝合接触面的运行状态,使实验运行时间延长至15 ms以上。实验结果表明,在相同的点火压力和点火温度下,甲苯的点火延迟时间比正癸烷的长。随着反应初始温度升高,甲苯和正癸烷的点火延迟时间缩短,点火延时的对数与温度倒数成正比。点火过程中的OH自由基荧光强度在不同温度下呈现出不同的变化规律。

Experimental Study of Measuring the Ignition Delay Time of Toluene and n-Decane by a Shock Tube

The ignition delay times of toluene/O₂/N₂ and n-decane/O₂/N₂ were obtained in a reflection type shock tube, via measuring the shock pressure signal and the OH radical emission intensity signal using a measurement system consisting of pressure sensors, photomultiplier tubes and an oscilloscope. The experiment conditions are over the temperature range from 1175 K to 2023 K, pressure at 0.1 MPa and equivalence ratio of 0.5, 1.0 and 2.0. In the experiment, liquid fuel was atomized into fuel aerosol by the supersonic atomizer. Long shock tube dwell time (about 15 ms) was achieved by tailored contact surface operation under such conditions. Results show that the ignition delay times of toluene is longer than that of n-decane at the same ignition pressure and ignition temperature. With the increase in initial reaction temperature, the ignition delay times of toluene and n-decane shorten. The logarithm of ignition delay times is directly proportional to the reciprocal of temperature. The fluorescence intensity of OH radical in ignition process reveals different change rule at different temperature.