Study On New Type Primary Cartridge For Mortar Bomb

The paper studies on the primary cartridge which adopts burning train of metal central squib for mortar bomb so that the output of tail pressure of the primary cartridge which is loaded small particle propellant is stable.The following points are described in the paper: the function principle of primary cartridge is analyzed;the structure of primary cartridge which adopts metal central squib is designed;the optimizing design scheme of metal central squib is prepared according to the test results;the function effects of primary cartridge with different water content of paper tube are analyzed and tested;the stress of tube seat during the function is calculated with numerical simulation.The conclusions of the paper are as follows:1.it is the developing trend to load small particle in the primary cartridge;it is the best choice that the structure of metal central squib is adopted to solve the problem about fire consistency of small particle propellant.2.Burning train:primer firing→igniting the black powder in the firing container→igniting the black powder in the central tube→burning or breaching half container→igniter pressure even happening in the central tube→breaching paper outside the central tube by igniter pressure through fire holes→firing propellant.3.The test results show the followings:(1) the tail pressure of primary cartridge is not bad affected by materials of metal central squib;the ejecting holes are evenly in rows at the range of bomb tail,and the tail pressure of primary cartridge is influenced lightly by the position and size of ejecting holes under the condition of same range of bomb tail;(2) the intensity of half container is not higher because it worse affects the tail pressure;(3) the black powder in the central tube make the worst influence to the tail pressure;(4) the water content of paper tube is designed 6%-9%;the tube seat may fall back when the water content is lower;4.the stress of tube seat is the biggest in the flange sharp-angled and expanded slot through analyze and calculate the stress of tube seat during function;the thickness of this place should be controlled.