Solid Rocket Ramjet Combustion Chamber Performance

The solid ducted rocket (SDR) combines the advantages of solid propullant rocket and ramjet propulsion. It offers considerable advantages for missile propulsion, such as high specific impulse, high speed, light weight, long range, high maneuver and simple structure. As the major direction of the propulsion system for supersonic missle, the ducted rocket has promising prospect.It is one of the key techniques for SDR to enhance mixing and increase combustion efficiency of fuel-rich gas and air in combustor. Mixing and combustion process are very complex, and there are many factors affect combustion efficiency. To enhance mixing and obtain high combustion efficiency, relationship must be found between structure/flow parameters and combustion efficiency. The purpose of this paper is to investigate the mixing and combustion process in ramjet combustor, finding the approach for increasing combustion efficiency of choked SDR.Using RANS equation, RNGk-ε turbulent model and Eddy Break-Up model, three dimensional flow-fields were numerically simulated in combustor of choked SDR, the relationship between structure/flow parameters and mixing/combustion efficiency was analyzed, and many results were found which are listed as follows: 1. The complex flow-field contains head recirculation and axis vortex that relate construction of the combustor; 2. With the decreasing of the size of air-inlet, air momentum increases and the recirculation and vortex intensifies, causing mixing and combustion efficiency increase; 3. With the increasing of air-inlet angle, radial momentum of air increase and mixing and combustion efficiency increase; 4. With the adding of fuel injector number, fuel enters into the combustor more dispersedly, and mixing and combustion efficiency increase. 5. With the increasingof injector expansion ratio, mixing and combustion efficiency increase. 6. With the increasing of air/fuel ratio, mixing and combustion efficiency increase. 7. With the increasing of pressure of gas generator under less injector number and expansion ratio, combustion efficiency increase.Experimental validation and performance evaluation method through temperature field measuring in the secondary combustor of SDR was developed. A subscale SDR and thermo-rake were designed, direct connection experiments were carried out, along with numerical simulation using experimental data as boundary condition. The experimental results agree to a certain extent with the numerical simulation indicates that this validation method is effective.