Development of Regression Formulas for CAMUI Type Hybrid Rockets as Functions of Local O/F

Regression formulas for solid fuels in CAMUI type hybrid rockets were developed as functions of local O/F. The alternative fuel grain design used in this rocket consists of multiple stages of cylindrical fuel blocks with two ports. A fuel block in a CAMUI type grain has three burning surfaces, i.e., the upstream end face, port inner walls, and the downstream end face. A series of static firing tests by a laboratory model motor revealed controlling parameters to develop a regression formula for each burning surface. Some empirical constants in the regression formulas depend on local O/F. Based on these findings, regression formulas as functions of local O/F were developed for a 2500 N thrust class flight model motor. Obtained regression formulas contribute to obtain an optimal design of a grain configuration to minimize the weight of residual fuel mass and c * loss due to the O/F shift during firing.