Performance Variation of Transient Propulsion System Induced by Machining Errors in a Variable Combustion Chamber

Gun propulsion is a special mechanical system where machining errors in its components are inevitable. In particular, the gun barrel, which constitutes the internal combustion system, will be subject to structural changes caused by machining errors, leading to variations in propulsion performance. To comprehensively assess the reliability of the system, this study utilizes a coupled model that facilitates the simulation of the mechanical interaction between projectile and barrel, effectively capturing the system's nonlinear kinematic properties and the combustion behavior of propellant within the variable chamber. A classical simplified combustion model is used to improve computational efficiency without compromising the accuracy of critical performance predictions associated with the propulsion system. The model incorporates variations in the internal structure of the barrel due to machining errors and has been validated through comparison with experimental data. Based on the validated model, the performance variations of the propulsion system when it has machining errors are investigated. Additionally, the axial distribution of the core flow state parameters of propellant gas within the barrel is presented. The findings offer a profound understanding of the impact of structural precision on gun performance and provide valuable insights and recommendations for optimizing gun design.