Theoretical and experimental investigations have been made to predict the performance of a backward-curved blade centrifugal pump. A mathematical model based on steady twodimensional incompressible Navier-Stokes (N-S) equations has been developed. The numerical solution was made using the primitive variables with artificial compressibility. The predictorcorrector method proposed by MacCormack was employed. The use of this technique involved imaginary rows behind walls, and periodic boundaries at far upstream and downstream which adequately improved the convergence to the solution. Based on this model a computer code has been developed and used to predict the flow pattern inside the pump and to determine the pump characteristics. A test rig was used to measure the real pump characteristic at controlled flow rates. Comparison of calculated and measured pump characteristic showed good agreement. Examination of the flow pattern at different flow rates might be useful to interpret the many performance features of the pump.

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The work aims at the experimental and theoretical determination of the effect of the air addition on the performance of solid propellant Integral Rocket-Ramjet Motors 1RRM's. An experimental investigation was carried out to determine the specific impulse dependence on the air equivalence ratio, using an 80 mm motor with exchangeable external and intermediate nozzles. Air inlets and secondary combustion chamber were kept unchanged. The ducted air by ram effect was simulated in this ground testing by feeding pressurized air into the secondary combustion chamber. The experimental investigation showed that the motor specific impulse was increased by about 85% when the air equivalence ratio was increased from zero to ..bout 0.7. one dimensional mathematical model of a solid propellant steady state is presented. The numerical calculations the presented model showed good agreement with the test

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