Research On Compartment Double Pulse Engine For A Rocket

With the increasing requirements of modern combat weapons,the dual-pulse solid rocket motor has made up for the shortcomings of conventional solid rocket motors with its outstanding advantages of better energy controllability,and greatly improved the comprehensive performance of missile weapons.In this paper,the double-pulse engine is taken as the research object,and the cross-shaped and star-shaped metal diaphragm isolation devices are designed.Then,the transient process of II pulse ignition is numerically simulated.Finally,the influence of different interstage channel diameters on the flow field characteristics and the coupled heat transfer analysis of I pulse insulation layer are studied and analyzed.The specific work is as follows:The designed compartment structure includes a support frame and a metal diaphragm.In order to verify the reliability of the compartment device,the numerical simulation analysis ofⅠ pulse pressure bearing and II pulse opening process of the two compartment devices was carried out respectively.The results show that the supporting frame greatly improves the bearing capacity of the metal diaphragm.The opening pressure of the cross-shaped metal diaphragm with thickness t=2mm and groove depth h=1mm is 3.02 MPa,and the opening pressure of the star-shaped metal diaphragm with the same size is 2.82 MPa.The prefabricated groove can effectively avoid the randomness of the diaphragm rupture and control the rupture size.The longer the build-up pressure time,the longer the diaphragm opening time,while the opening pressures of the two kinds of diaphragms are stable at 3.2MPa and 3MPa respectively.The opening pressure decreases approximately linearly with the increase of the preset defect groove depth h;First of all,the feasibility of numerical simulation of II pulse ignition transient process is verified by numerical example verification,and the characteristics of combustion chamber flow field at different times during II pulse ignition transient process are studied and analyzed.The results show that before the compartment is opened,a high-pressure zone is formed at the end of II pulse combustion chamber.When the compartment is opened for 2.9ms,high-temperature and high-pressure gas expands and injects into I pulse combustion chamber to form pressure waves,which causes the oscillation of combustion chamber flow field.On the other hand,the larger the opening pressure of the bulkhead metal diaphragm,the larger the pressure drop and the longer the opening time of the ⅱ pulse combustion chamber,the larger the mass flow of ignition gas,the shorter the time for the first ignition of propellant and the complete ignition of propellant surface,and the faster the pressurization rate of combustion chamber;Steady-state numerical simulation calculation and analysis are carried out for the second pulse working stage,and the influence of different inter-stage channel diameters on the flow field characteristics is studied and analyzed,and the coupled heat transfer of the first pulse insulation layer is analyzed and studied through the unsteady flow-heat coupling simulation calculation.The results show that when the gas in the second pulse combustion chamber enters the first pulse combustion chamber through the interstage hole,the phenomenon of backward step flow will occur,forming a recirculation zone.When the interstage hole is smaller than the inner hole channel of the grain,the "gathering" effect is particularly significant,and the region with the highest surface temperature of the insulation layer is just in the recirculation zone formed,and the region upstream of the reattachment point.