Study On The Method Evaluating The Launch Safety For Gun Propellant Charge

Launch safety problem of gun propellant charge badly restricts to improve the performances of modern gun, has already become to a worldwide difficulty that are paid attention by weapon experts and dynamicists. Up to the present, launch safety of gun propellant charge can not be evaluated in our country. In order to provide theoretical foundation and test method to identifying launch safety for gun propellant charge scientifically, this paper focuses on obtaining the criterion for launch safety of gun propellant charge, and based on which, founding a method evaluating launch safety for gun propellant charge. The main contents are as follows:1) The DCD scheme is successfully applied to develop a new computational method on two-phase-flow interior ballistics, it need not factitious viscidity or filtering, also need not two different schemes for two phases, gas and solid respectively. The influence of fracture degree of propellant bed on the launch safety is simulated more exactly with numerical method.2) The mechanism causing launch safety problems of gun propellant charge is studied. Some new understanding to safety procedure based on sensitivity tests of pressure wave is discussed also. The evaluation procedure for launch safety of gun propellant charge based on the fracture degree of propellant bed should be developed in the field.3) The concept of relative initial dynamic vivacity is developped, a new method for describing fracture degree of propellant is developed, and its correctness and feasibility are validated by computation and test results respectively. The shape characteristic parameters of fracture propellant are acquired with computational method.4) The technology breakthrough of physical simulation for compression and fracture of propellant bed in low temperature is achieved. The quantitative relation between fracture degree of propellant bed and compression stress is established with invented physical simulation system and plenty of test results.5) Based on series physical simulation, the criterion and evaluation methd for launch safety of gun propellant charge are put forward. Tests show that the method is applied and effective.6) Applied the criterion and evaluation method, interior ballistic performance of an equilibrium launcher and its deficiency in launch safety are analyzed, the measure to improve its design is pointed out.The study results on theory and technology will provide a foundation to build a new identifying test method for launch safety of gun propellant charge, and provide theoretic basis and technology support to ensure the using safety of weapon equipment of gun and ammunition and to improve the performances of modern gun and ammunition.