Design of Long-Stroke ejector with Traveling Charge Structure

Abstract

Abstract Generally, the independently designed charge is used in traditional ejectors, where the gunpowder is usually fixed at its end. For long-stroke ejectors, the energy from gunpowder combustion in the later period of piston movement is mostly used for structure expansion, and only a small part is converted to piston actuation. The energy for piston movement can only be improved by increasing the amount of gunpowder, which results in large instantaneous pressure in the combustion chamber, thus leading to a big impact on the system structure by the pyrotechnic products. To deal with this problem, a design method for the long-stroke ejector based on traveling charge structure is proposed. It integrates the charge structure with piston design to ensure that the energy from gunpowder combustion can fully act on the bottom of the piston during the whole combustion process, thus improving the proportion of energy from gunpowder combustion transformed to the piston’s kinetic energy and reducing the charge quantity, which will then lessen the impact of pyrotechnic products on the system structure and improve its reliability. It has been experimentally proven that when designing a long-stroke ejector, the energy utilization rate of gunpowder can be increased by about 1.5 times by adopting the traveling charge structure compared to the traditional charge structure.