点火延迟时间对铝粉爆炸特性参数的影响

为了研究装置点火延迟时间对不同浓度粉尘爆炸压力和压力上升速率的影响，以铝粉为介质在5L圆柱形爆炸装置中进行系列爆炸实验。结果表明：装置点火延迟时间对铝粉爆炸压力和压力上升速率有十分显著的影响，且存在一个最佳点火延迟时间，此时最大爆炸压力最大；随着铝粉浓度的增加，最佳点火延迟时间先增加后保持不变。最佳点火延迟时间下的最大爆炸压力和最大压力上升速率明显高于点火延迟时间固定为60s时的。相对粉尘不同浓度均采用固定点火延迟时间，不同浓度时采用最佳点火延迟时间，所测得的粉尘最大爆炸压力和最大压力上升速率明显符合实际。

Effects of ignition delay time on characteristic parameters of aluminum dust explosion

According to the time effect of particle dispersion and sedimentation during the dust cloud formation, the paper points out that the internationally accepted method that only by the gas phase turbulence degrees or single dust concentration to set the fixed ignition delay time, is of uncertainty.To investigate the effects of the ignition delay time on the dust explosion pressure and the pressure rise rate, a series of explosion experiments were carried out in a 5－L cylindrical vessel filled with aluminum dust.The results show that the ignition delay time has a significant effect on the measured values of the explosion pressure and the pressure rise rate and there exists an optimum ignition delay time to maximize the explosion pressure.With the increasing of the dust concentration, the optimum ignition delay time increases gradually to the maximum and then remains unchanged.The maximum explosion pressure and the maximum pressure rise rate under the optimum ignition delay time are obviously higher than those under the fixed ignition delay time of 60ms.If the fixed ignition delay time of 60ms is used for all the aluminum dust with different concentrations, the measured maximum explosion pressure and the maximum pressure rise rate may largely deviate from the actual values.