The effects of thermal gradients on Performance of End‐Burning Rocket Motors

Abstract

The effect of a non‐uniform temperature distribution on the thrust‐time performance of an end‐burning solid propellant rocket motor charge is examined. It is shown that non‐planar surfaces develop. For some classes of temperature distribution, the effect of these non‐planar surfaces os always between the limits of the thrust predicted at the maximum and minimum temperatures. The class of temperature distributions that meet this criterion is determined and a simple inequality is derived to test any actual distribution. An expression for the departure from specification is given for distributions outside this class. These results partially justify the proof of ballistic design by testing motors of uniform temperature at upper and lower limits, when service motors may be exposed to uneven heating. The validity of such testing in actual cases can be determined.