HE actual physical phenomena occurring during the flame spreading period in solid propellant rocket motors are exceedingly difficult to analyze in an exact fashion. Thus a somewhat simplified mathematical model should be used to obtain the pressure response in a solid propellant rocket at the first period of performance. The problem of solid propellant ignition has received considerable study due to its importance in rocket technology. Different investigations have been performed to predict the internal ballistics in this phase. 1-7 Different types of igniters were used in the performed studies such as ignition by hot wires or gasless igniters. In addition, efforts have been made to describe the ignition response of solid propellant. The so called thermal ignition theories treat ignition in term of solid temperatures. Some experimental measurements were carried out on the ignition response to radiative and conductive heat transfer. The studies have been concerned with evaluations of parameters such as ignition energy and ignition time which are assumed to be function of the chemical and physical properties of the propellant and the gaseous environment.

Prediction and control of the pressure-time history of solid rockets during early phases of operation often depend on understanding the complex interactions between elements like igniter gas flow, convective heating, flame spreading, the developing flow field, and radiation effect. Typical design and analysis goals are: to reduce the overpressure that sometimes accompanies ignition and to reduce the ignition delay time and increase the ignition reliability in a tactical missile.