Theoretical performance of frictionless magnetohydrodynamic-bypass scramjets

Theoretical performance calculation is made of a scramjet propulsion system incorporating a magnetohydrodynamic (MHD)-energy-bypass scheme. The MHD ge nerator upstream of the combustion chamber slows down the Row so that the M ach number at the entrance of the combustion chamber is kept below a specif ied value, The MHD accelerator downstream of the combustion chamber acceler ates the Row, expending the electrical power produced by the generator. The Row is seeded with potassium or cesium, and the MHD devices operate as Far aday machines, Friction is neglected, and chemical equilibrium is assumed e verywhere except in the nozzle downstream of the freezing point, The calcul ation shows that the MHD-bypass scheme can improve specific impulse over th at of a conventional scramjet at Eight speeds over 3.5 km/s, At speeds belo w about 6 km/s, the calculated specific impulse fan be higher than that of a typical rocket engine, Consequently, the MHD-bypass scheme can extend the operational range or improve the performance of a conventional scramjet en gine.