Design Of Dust Explosion Parameters Test System And Study Of Multi-Spark Electrostatic Discharge

Dust explosion characteristics testing usually uses chemical ignition apparatus as the standard ignition source,however,chemical ignition apparatus has the problems are difficult to obtain,high danger,and uneven flame propagation,etc.,which makes dust explosion research difficult.Electrostatic ignition is widely used in the field of physical hazard testing of hazardous chemicals Dute to its easy generation and control,adjustable energy,and stable spark.In this paper,we conduct some work to investigate the feasibility of using electrostatic ignition instead of chemical ignition,as follows:Firstly,we have an in-depth understanding of dust explosion mechanism,explosion conditions and influencing factors;we compare and analyze domestic and international dust explosion related testing standards;we also analyze the dust explosion pressure curve from the time scale and flame thickness;we also introduce two methods of dust explosion classification.Secondly,we designed and built a dust explosion parameter testing system,which consists of a 20L spherical explosion parameter testing device,a multi-spark electrostatic generation device,a dust explosion measurement and control system and human-computer interaction software,which can realize the standard dust explosion characteristic parameter testing(test pressure range 0～3MPa)and 1～4 spark electrostatic ignition mode(spark energy range 0～20J)function.We have also conducted experiments with standard dusts of lycopodium and measured their maximum explosion index of 22.43 MPa.m/s.The test results are consistent with published literature and the experiments have verified the reliability and accuracy of the test system.In addition,we have calculated the loop resistance and loop inductance parameters by building a multi-spark electrostatic generator and establishing an equivalent discharge model.The time-varying characteristics of the spark resistance and spark inductance were verified by comparing the fixed parameter fitting method with the time-varying parameter fitting method.We also use the I~2R integration method to calculate the discharge energy accurately,to avoid the phase deviation problem caused by the UI integration method.Finally,by conducting experiments to analyze the factors influencing electrostatic ignition,we found that increasing the spark energy and the number of sparks could increase the dust explosion index and shorten the induction time,but had less effect on the explosion pressure.We also compared four-spark electrostatic ignition with chemical ignition for anthraquinone and lycopodium dusts and found that electrostatic ignition resulted in lower explosion indices,longer induction times and smaller deviations in explosion pressures.We also compared the test data with published literature and found that the lower test results for electrostatic ignition compared to chemical ignition were due to the range of ignition,as electrostatic ignition is only a single point of ignition,whereas chemical ignition triggers multiple points of ignition,increasing the total flame area,accelerating the burning rate in the explosion and increasing the explosion index.