Recent progress in the prediction and analysis of the operation of solid rocket motors

Abstract

The development of big segmented solid rocket motors during the nineties has been supported by an important progress in science and computational tools. This progress is largely related to the solution of various technical problems in the design and processing of the propellant grains and their effect on the motor operation. It has been possible because of the enormous increase in the available computing power. After a review of the main problems encountered (grain-flow coupling, motor trace shape prediction, pressure oscillations, slag deposit etc...) recent developments in modeling are described in two areas related to the analysis and prediction of motors operation. The first development couples the propellant surface burnback and pressure field computations during the whole operation of the motor: real tune geometry, pressure field and local burning rates are calculated in order to achieve a much more precise prediction of the motor trace. Pressure oscillations and instabilities are also predicted. The second development is related to the influence of the process, through the rheology of the propellant on the combustion of the propellant. Rheology and particle segregation under shear may explain such effects as the so-called ⪡hump⪢ and ⪡knitlines⪢ effects. Experimental and modeling work in the field are described.