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Abstract:
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A computational fluid dynamics code for two -dimensional , multi -species , laminar Navier -Stokes equations is developed to simulate a recently proposed engine concept for a pulsed detonation based propulsion system and to investigate the feasibility of the engine of the concept .The governing equations that include transport phenomena such as viscosity , thermal conduction and diffusion are coupled with chemical reactions . The gas is assumed to be thermally perfect and in chemically non -equilibrium . The stiffness due to coupling the fluid dynamics and the chemical kinetics is properly taken care of by using a time -operator splitting method and a variable coefficient ordinary differential equation solver . A second -order Roe scheme with a minmod limiter is explicitly used for space descretization , while a second -order , two -step Runge -Kutta method is used for time descretization . In space integration , a finite volume method and a cell -centered scheme are employed . The first -order derivatives in the equations of transport properties are discretized by a central differencing with Green's theorem . Detailed chemistry is involved in this study . Two chemical reaction mechanisms are extracted from GRI -Mech , which are forty elementary reactions with thirteen species for a hydrogen -air mixture and twenty -seven reactions with eight species for a hydrogen -oxygen mixture . The code is ported to a high -performance parallel machine with Message -Passing Interface . Code validation is performed with chemical kinetic modeling for a stoichiometric hydrogen -air mixture , an one -dimensional detonation tube , a two -dimensional , inviscid flow over a wedge and a viscous flow over a flat plate . Detonation is initiated using a numerically simulated arc -ignition or shock -induced ignition system . Various freestream conditions are utilized to study the propagation of the detonation in the proposed concept of the engine . Investigation of the detonation propagation is performed for a pulsed detonation rocket and a supersonic combustion chamber . For a pulsed detonation rocket case , the detonation tube is embedded in a mixing chamber where an initiator is added to the main detonation chamber . Propagating detonation waves in a supersonic combustion chamber is investigated for one - and two -dimensional cases . The detonation initiated by an arc and a shock wave is studied in the inviscid and viscous flow , respectively . Various features including a detonation -shock interaction , a detonation diffraction , a base flow and a vortex are observed . |