Numerical and Experimental Performance Comparison of a Typical Swirl Co-Axial Injector for a Cryogenic Combustor

A swirl co-axial injector is designed, fabricated and tested for a cryogenic combustor using liquid oxygen and gaseous hydrogen. Performance of this injector arrived at through experimental and numerical studies are compared in terms of chamber pressure. The numerical model developed for this injector and combustor is based on a Eulerian–Eulerian framework. It considers the two-phase flow of liquid oxygen and gaseous hydrogen with the assumption of local mechanical and thermal equilibrium, but with a local finite evaporation rate. Chemical reaction of gaseous oxygen and hydrogen is modelled with a modified eddy dissipation concept combustion model. It is found that the chamber pressures calculated by this model matches reasonably well with the test results. The steady-state chamber pressures obtained are 38 bar and 40 bar for experimental and numerical studies, respectively. Further, the numerical results are analysed to understand the flow field characteristics, such as evaporation and mixing, in the tested injector. It is found that the evaporation of the liquid oxygen is complete well within the first quarter and the combustion is almost complete in the three quarters, respectively, of the injector length.