Experiments on supersonic combustion ramjet propulsion in a shock tunnel

摘要: Measurements have been made of the propulsive effect supersonic combustion ramjets incorporated into a simple axisymmetric model in free piston shock tunnel. The nominal Mach number was 6, and stagnation enthalpy varied from 2.8 to 8.5 MJ kg-1. A mixture 13% silane 87% hydrogen used as fuel, experiments were conducted at equivalence ratios up approximately 0.8. measurements involved axial force on model, using stress wave balance, which is recently developed technique for measuring forces tunnels. net thrust experienced 3.7 kg-1, but increased, an increasing drag recorded. Pitot static pressure showed that supersonic. results found compare satisfactorily with predictions based established theoretical models, some simplifying approximations. rapid reduction seen arise precombustion temperature, showing need control this variable if performance be maintained over range enthalpies. Both inviscid viscous relatively insensitive enthalpy, chambers making particularly significant contribution drag. maximum fuel specific impulse achieved only 175 s, theory indicates there considerable scope improvement through aerodynamic design.