Cold tests and the dynamic characteristics of the pintle type solid rocket motor

Dynamic characteristics of a pintle-perturbed conical nozzle are studied theoretically, experimentally, and numerically under the condition of constant mass flow rate. Conventional one-dimensional nozzle theory in conjunction with a two-dimensional axi-symmetric flow solver calculates the internal flow parameters in the nozzle equipped with the pintle. The commercial flow solver is used based on the strongly-coupled flow equation system which is closed with one-, or two-equation turbulence models. Theoretical and numerical flow parameters are properly validated by the experiments. For the dynamic characteristics of the pintle nozzle, performance variations are examined in terms of the free volume size, the pintle actuating speed and pintle geometries. The dynamic characteristics of the pintle-perturbed nozzle largely depend on the mass flow rate through the nozzle throat which is a strong function of the reduced throat area and chamber pressure. It also depends on the pintle activation because the nozzle throat and the chamber pressure change with the extent of the pintle displacement.