Investigations on the influence of swirl intensity on solid-fuel ramjet engine

In this paper, the influence of swirl intensity on solid fuel regression rate and combustion phenomena in a solid fuel ramjet has been investigated numerically and experimentally. First, an in-house code has been developed to solve axisymmetric Reynolds-averaged Navier-Stokes equations of unsteady turbulent swirling compressible flow field with chemical reactions. Second, experiments have been conducted in a solid fuel ramjet without swirl to validate the developed code for solid fuel decomposition; then the predictive capability of the code is validated by using; swirling flow passes through sudden expansion combustor, shock-induced combustion case, and a semi-infinite plate. Third, unsteady simulations are carried out for reacting turbulent flows with and without swirl in a solid fuel ramjet using high-density polyethylene (HDPE) solid fuel. Then, the computational results are analyzed and discussed. The results show that, the presence of swirl is more effective in enhancing the regression rate and the turbulent mixing throughout the ramjet. Increase swirl number increases the heat and mass transport at the fuel surface and hence increases the regression rate.