Numerical study of mixing and combustion performance for magnetohydrodynamic-bypass scramjet

In order to study the mixing and combustion performances of magnetohydrodynamic (MHD)-bypass scramjet (AJAX), the three-dimensional numerical methods were used for the MHD generator flow and the chemical reaction flow, respectly. The combustion entrance conditions were varied by altering the MHD conditions, the mixing efficiencies and combustion efficiencies were got. The results show that as the magnetic field strength increases or load factor decreases, the mixing efficiency is increase, the improved maximum value of mixing efficiency is 11.6%. In the front part of chamber where the thermal dissociation is not sensible, the combustion efficiency is increase; in the latter part of the chamber, while the thermal dissociation is no present, the combustion efficiency are increase, the improved maximum value of combustion efficiency is 6.5%, the combustion chamber is shorten by 25%, reduce the geometric sizes and mass of the vehicle; while the thermal dissociation is present, the combustion efficiency are reduced even lower than the no-MHD case, so it should try to avoid larger magnetic field strengths or smaller load factors to reduce the temperature of the combustion entrance, which cause the thermal dissociation reduce the combustion efficiency.