Study Of Ignition Powder Burning Rate Law And Ignition Ability Under Low Pressure Environment

The inadequate and ineffective ignition of ignition powder under high altitude environment is an existing problem,and one of its main reason is the great changes of burning rate and ignition ability under low pressure environment.In order to explore the burning rate law and ignition ability of the ignition powder under low pressure environment.In this paper,burning rate and ignition ability to ignite the Mg/PTFE of black powder,B/KNO3 and B/BaCrO4 are investigated under different low pressure environment.First,B/KNO3 and B/BaCrO4 are prepared by ball mill method.The DSC curves show that the exothermic peak temperature of B/KNO3 by ball mill method is 45 ℃ lower than that of B/KNO3 by mechanical mix method,the exothermic peak temperature of B/BaCrO4 by ball mill method is 12℃ lower than that of B/BaCrO4 by mechanical mix method.Secondly,the burning rate of black powder,B/KNO3 and B/BaCrO4 are tested under different low pressure.The results show that the black powder appears misfired and shut down under 20 kPa.The burning rate of black powder and B/KNO3 are linear relationship with the environment pressure,while B/BaCrO4 is a exponential relationship.The burning rate goes up with the increase of initial temperature,and the influence of environmental pressure is greater than that of initial temperature.The burning rate of black powder and B/KNO3 are influenced by initial temperature with the same,but the lower the environment pressure is,the greater influence on burning rate of B/BaCrO4.The burning rate of ignition powder gose up with the increase of environment pressure,the pressure index of gas production ignition powder is I while the pressure index of less gas production ignition powder is larger than 1.Finally,we study the minimum initiating charge of black powder,B/KNO3 and B/BaCrO4 to ignite Mg/PTFE under low pressure environment.The results indicate that the minimum initiating charge increase with the environmental pressure decrease.Black powder and B/KNO3 cannot ignite Mg/PTFE when the environmental pressure reduces to 40kPa.B/BaCrO4 could ignite Mg/PTFE under any low pressure envirionment,which is the best ignition powder under low pressure environment.