Application Of Preconditioning Methods In Numerical Simulation For All Speeds And Chemical Non-Equilibrium Flows

All speeds control equations were deduced from traditional compressible equationswith precondition method and applied to 2D inviscous/viscous flows at all speeds. Jamesoncentral difference scheme, LU-SGS implicit iterative method and round-off control were usedto accelerate convergence rates and improve numerical precision. Computations were carriedin the bump flow in a channel, viscous cavity flow and nozzle flow. Numerical results werecompared with standard cases, which proved that methods can eliminate stiffness of theequations in low Mach flow and programs had precision and credibility. Furthermore,Chemical non-equilibrium all speeds control equations were deduced from traditionalcompressible equations with precondition method. Chemical source in equations wasconducted implicitly to remove stiffness. Seven species and eight equations were used tocompute reaction between hydrogen and oxygen. Computations were carried in reacting shearlayer. results were compared with experiment, which proved that methods and programs hadprecision and credibility. All these works built foundations for further study of integratedFlow in combustor and nozzle in combustor and nozzle.