Igniter Combustion Characteristics Of The Study

The igniter researched in this paper is the key part of base bleed extended range projectile. The 3 base formulations in this paper was made up of Ba(NO₃)₂, KClO₄, Sr(NO₃)₂, Mg ,Al, which were added Fe_xP_y, Zr and graphite to form five different kinds of igniting powder. Formulation 1: Ba(NO₃)₂:Mg:Al:Fe_xP_y: NC; Formulation 2: KClO₄:Mg :Fe_xP_y : NC; Formulation 3: Sr(NO₃)₂:Mg: Fe_xP_y: NC; Formulation 4: Ba(NO₃)₂ :Mg :Al:Zr: graphite: NC; Formulation 5: KClO₄:Mg: Zr: graphite: NC. Finally two formulations were determined according the analysis of the comparison of the characteristic parameters and combustion tests, the igniters filled with which were researched under the static state, high decompression grads condition, high-speed rotary condition, and high-speed airflow disturbance condition.Under the static state, the influence of the pressure of charge pressing, charge mass on burning rate and flame area were researched. The results show that the burning time achieves the longest for Formulation 1 and 4 when the pressure of charge pressing is 17.56MPa while for Formulation2 and 5 is 13.65MPa and for Formulation 3 is 23.41MPa. The combustion time is markedly longer when Zr or graphite were added, being 23.35% longer at most than that of the formulation which contains Fe_xP_y and even 40% longer than base formulations. The flame area of Formulation 2 and 5 are bigger, and the flame areas of other formulation changes not obviously when the proportion changes. There is little influence of regulation powder on the combustion heat and combustion temperature of igniting powder. For the formulations containing Fe_xP_y, the combustion residue is too much when the Fe_xP_y is more than 15%, and it is prone to jam the igniter. The ignition becomes difficulty when the graphite is more than 3%. The strongest moisture absorption is formulation 3 while there are little moisture absorption with formulation 1 and 4. The moisture absorption rate of Formulation 4 is only 0.800%. The ignition capability of Formulation 4 and 5 is obvious better according to the results of ignition capability tests.Through the tests above and analysis above, the Formulation 4 and 5 were selected as better formulation, the igniter with which can combust continuously and steadily under the conditions of high decompression grads without misfire or cut-off deflagration. Under the high-speed rotary condition, the combustion time declined obviously, and the burning rate increased obviously, achieving about 30mm/s, being 2 times more than that under the static state, and the flame area is obvious larger than that under the static state. Under the high-speed airflow disturbance condition, the combustion time of the igniter declined when the Mach number increased, the combustion was fierce, and the flame length was several times longer then that under the static state. The ignition and combustion under the flow fields with different Mach numbers were been numerical simulation using FLUENT, acquiring the stimulant graphs and curves of the burning rate, temperature and pressure, and the simulation result is similar to the tests result.The igniters used in this paper can ignite and combust steadily and reliably under the conditions above.