Cold Pressurization Test and Simulation of Structural Deformation of High-energy Solid Propellant Grain

To study the structural deformation of high-energy solid propellant grain during ignition process at room temperature, cold impact tests on a 200mm diameter cylindrical solid rocket motor (SRM) structure tester loaded with nitrate ester plasticized polyether (NEPE) propellant under actual building pressure conditions of 8.65 MPa, 269 ms and 7.48MPa» 264ms at room temperature were conducted using a newly established all liquid medium cold pressurization testing system. Meanwhile, based on finite element numerical simulation, the volume change rate of the grain for the tester under building pressure conditions of 7.5—9.0MPa and 250—400ms. The experimental results show that the pressure—time curves of the inner hole of the grain and the displacement—time curves of the piston for the volumetric flow device have good repeatability and consistency, and the variation characteristics of the pressure—time curves are consistent with the successful ignition test results of the real SRM. As the pressure building conditions increases from 7.48 MPa and 264 ms to 8. 65 MPa and 269 ms, the pressure building rate increases from 28.33 MPa/s to 32. 16MPa/s» and the volume change rate increases from 1.14% to 1.27%. The numerical simulation results show that the volume change rate of the grain under the building pressure conditions of 7. 48MPa, 264ms and 8.65MPa, 269ms is 1.13% and 1.29%, respectively. The relative error with the experimental result is 0.88% and 1. 57%, respectively. Therefore, the all liquid medium cold pressurization testing system can safely and effectively simulate and test the structural deformation of high-energy SRM propellant grain during ignition at room temperature. Secondly, under the pressure conditions of 7.5—9.0 MPa and 250—400 ms, the volume change rate of the grain shows a linear increase trend with the increase of time and pressure. Moreover, compared with the time, the pressure has a more significant impact on the volume change of the SRM grain with NEPE high-energy solid propellant grain.