Experiments On Explosion Venting And Suppression Of Aluminum Dust

Studies on ducted venting of dust explosion have a significance for the industrial dust explosion protection. The existence of duct will make the main vessel’s maximum explosion venting overpressure significant increase. Currently the main factors of this anomaly has not been studied clearly. This paper did a lot of experiments in the Aluminum dust explosion venting based on the1.3L Hartmann tube.The main contents and conclusions are as follows:(1) The1.3L Hartmann tube has been improved, and designed many relief pipess with different length and diameter. Flame and pressure sensors were installed in the relief pipes, so that the pressure and flame propagation characteristics would be analyzed. In order to ensure the synchronization of the data acquisition, two cards with8-channels has been used. A lot of experiments of Aluminum dust explosion simply venting, ducted venting, inerting and inhibition have been done based on this device.(2) The characteristics of Aluminum dust explosion simply venting were studied experimentally. The relationship between the three factors and the Pred,max and (dP/dt)red,max were found with using the SPSS software. It is found in the experiments of simply explosion venting that the effect extent of three factors on the Pred,max from strong to weak as follows:the diameter of explosion venting, the particle size of aluminum dust,the Concentration of aluminum dust. The effect extent on the (dP/dt)red,max from strong to weak as follows:the particle size of aluminum, the diameter of explosion venting, the Concentration of aluminum dust.(3) The characteristics of Aluminum dust explosion ducted venting were studied experimentally with ducts of different length and diameter. Through the experiments the effect of concentration of aluminum dust, particle size of aluminum dust and the LT/φT of ducts on the characteristics of Aluminum dust explosion venting have been analyzed.The relationship between the three factors and the Pred,max,duct was found with used the SPSS software. It is found in the experiments that the effect on the Pred,max,duct from strong to weak as follows:the particle size of aluminum dust, the the LT/φT of ducts, the concentration of aluminum dust.(4) It is found in the ducted venting experiment that a secondary explosion in the duct have been found occurred inear the vent. The cause of the secondary explosions is the jet flame ignite unburned aluminum dust in the duct.The Secondary explosion is one of the reasons, which makes a significant increase in the maximum pressure of the main vessel.(5) It is a very cost-effective measures of dust-explosion prevention when explosion venting combines with explosion suppression. The effect of pipe lined with Aluminum silicate cotton porous media and premixed calcium carbonate inert particles in the Hartmann tube on the characteristics of Aluminum dust explosion ducted venting were Respectively studied.lt is found in the experiment that both the pipe lined with Aluminum silicate cotton porous media and premixed calcium carbonate inert particles in the Hartmann tube can effectively reduce the intensity of secondary explosions in the duct, at the same time, the pressure and flame speeds are also significantly reduced within duct and Hartmann tube.(6) It is found in the experiment,the Pred,max and (dP/dt)red.max will be reduced with the increase of the concentration of premixing calcium carbonate in the Hartmann tube,but the changes of (dP/dT)red,max is more sensitive, it is also found that premixing calcium carbonate would make the Kst and Av effectively reduced.