Influence of nozzle arrangement on the combustion performance of particle-laden fuel-rich jet

The working process of a solid rocket scramjet can be summarised as the mixing and combustion of particle-laden fuel-rich jet(PFRJ) with supersonic airflow. A numerical simulation study was carried out to determine the influence of nozzle arrangement on the combustion of PFRJ. The effects of three factors, namely the number, angle and position of nozzles, on the combustion of PFRJ with supersonic airflow were investigated in terms of flow parameters, combustion efficiency, temperature distribution and particle trajectory, respectively. The results show that: (1) Increasing the number of nozzles increases the contact area between the PFRJ and the supersonic airflow. Increasing the nozzle angle not only increases the penetration depth of the PFRJ, but also distributes them more widely in the span direction. (2) Nozzle angle has little effect on the combustion efficiency of PFRJ. However, when the nozzle position is arranged on both sides, the combustion efficiency of gas and carbon particles in PFRJ is significantly improved. (3) The gas and particles have the characteristics of zoned combustion. Too concentrated heat release from the gas is not conducive to particle heating and ignition. Particle combustion requires a high temperature and oxygen rich environment. How to create and introduce particles into a high temperature and oxygen rich environment is the key to improving particle combustion efficiency. The low combustion efficiency of boron particles has become the main reason for limiting the energy release of PFRJ.