Flow Matching Results of an MHD Energy Bypass System on a Supersonic Turbojet Engine using the Numerical Propulsion System Simulation (NPSS) Environment

Flow matching has been successfully achieved for an MHD energy bypass system on a supersonic turbojet engine. The Numerical Propulsion System Simulation (NPSS) environment helped perform a thermodynamic cycle analysis to properly match the flows from an inlet employing a MHD energy bypass system (consisting of an MHD generator and MHD accelerator) on a supersonic turbojet engine. Working with various operating conditions (such as the applied magnetic field, MHD generator length and flow conductivity), interfacing studies were conducted between the MHD generator, the turbojet engine, and the MHD accelerator. This paper briefly describes the NPSS environment used in this analysis. This paper further describes the analysis of a supersonic turbojet engine with an MHD generator/accelerator energy bypass system. Results from this study have shown that using MHD energy bypass in the flow path of a supersonic turbojet engine increases the useful Mach number operating range from 0 to 3.0 Mach (not using MHD) to a range of 0 to 7.0 Mach with specific net thrust range of 740 N-s/kg (at ambient Mach = 3.25) to 70 N-s/kg (at ambient Mach = 7). These results were achieved with an applied magnetic field of 2.5 Tesla and conductivity levels in a range from 2 mhos/m (ambient Mach = 7) to 5.5 mhos/m (ambient Mach = 3.5) for an MHD generator length of 3 meters. Nomenclature γ = specific heat ratio for air ηN(a) = enthalpy addition ratio of the MHD accelerator ηN(g) = enthalpy extraction ratio of the MHD generator ηs(a) = isentropic efficiency for the MHD accelerator ηs(g) = isentropic efficiency for the MHD generator πa = stagnation pressure ratio of the MHD accelerator πg = stagnation pressure ratio of the MHD generator πp = stagnation pressure ratio of the pre-ionizer σ = electrical conductivity χ = fraction of MHD generator power diverted to pre-ionizer Ag = cross sectional area of the MHD generator B = magnetic field intensity Cp = constant pressure specific heat K = Faraday loading parameter L = length of the MHD generator m