Résumé
The internal aerodynamics of a solid propellant rocket motor is studied. Cold gas simulation setups are reviewed. The analysis of numerical approximations used for modeling such setups has led to the adoption of a k-L type description of turbulence. The numerical simulations of two cold flow setups enable the computer code to be checked in purely aerodynamic terms. The experimental subscale setup which allowed the construction of a database regarding the quasi steady heat exchanges generated on an inert wall within the combustion chamber of a rocket motor is described. The computations show that an approximation which does not require the use of a very fine grid at the wall is sufficient to reproduce the measured flux levels. A law of the wall is proposed which takes account of the effect of the steep temperature gradients and allows a better description of the measurements made. The evaluation of the ablation of a thermal insulation material placed in the combustion chamber of the test rocket motor is described. Teflon was employed in view of the simplicity of its degradation mechanisms. In terms of measurements, the difficulties inherent in the use of an ultrasonic method are shown. The dimensional measurements made constitute reference data through which it will be possible to check future computer codes for the ablation of thermal insulation. The validity of coupling an aerothermodynamic computer code and a module for evaluating the response of an insulation material is discussed. A full temporal numerical simulation of the tests is presented. (ESA)