Design and experimental studies on ceramic port cover for dual pulse motor

Material and definition of dome-shaped ceramic port cover contour is presented. Two types of ceramic port covers with equal thickness and variable thickness structures are proposed. A group of cold-flow tests was carried out on a reusable dual pulse motor in which the performances of different port covers including sealing, first-pulse pressure bearing and second-pulse broken pressure were experimentally studied. A solid dual pulse motor for hot-firing test was designed, manufactured and statically tested. The feasibility of proposed bulkhead with ceramic port cover employed on actual solid dual pulse motor was proved. It is found that dome-shaped port cover made from machinable glass ceramic withstands a high pressure on its convex side, but is prone to fragmentation while imposing a reasonably low pressure on its concave side. The peripherally thickened port cover that is more robust in machining and assembly process is recommended. Grooves milled on the port cover induce fragmentation and are helpful to produce regular broken aperture shape. The bulkhead assembly consists of retaining ring, port cover and supporting ring can well fulfill the requirements of port cover in fixing, preloading and sealing. The broken fragments are less likely to damage the insulation structures of the combustion chamber and the nozzle unit which had been validated in the test.