Consistent definitions for burning-rate measurement in solid-rocket motors

Inherent problems in burning-rate measurement in small solid-rocket motors are discussed in terms of subfactors comprising an overall absolute scale factor. A set of data-analysis definitions for burning-rate measurement that is consistent with bulk-mode theory governing pressure in solid-rocket motors is presented. The procedure using these definitions specifically treats the effects of variable exponent, noninstantaneous burnout, mean propellant shrinkage, hardware variations, and nonneutral pressure to reduce bias and scatter in measured burning rates. The present procedure does not address the effects of heat losses, formulation gradients, or nonequilibrium burning. Application of the procedure on motor data is discussed briefly.