Study of one-dimensional averaging methods in scramjet flow field

Various averaging methods were introduced, including common mass or area weighted averaging method, including the conserved mass/momentum/energy (CMME) method and the conserved mass /energy/entropy (CMES) method. A model containing scramjet inlet and combustor was used to reveal the difference between different averaging methods, and effects of entrance data from different averaging methods on combustor one-dimensional analysis. Results show that the conserved methods are recommended when dealing with scramjet combustor. The CMME method can conserve accurate total pressure, while the CMES method will cause virtual total pressure loss, so the CMME method is recommended in dealing with total pressure recovery. In subsonic combustion mode, both conserved methods cannot predict the gradual compression in isolator. In supersonic combustion mode, the CMES method can hold better approximate conservation of momentum, which is worse in subsonic combustion mode. Combustor one-dimensional analysis results of entrance data from different averaging methods are compared. Derivation of Case 1 result by mass weighted averaging method is up to 27.8%, which by the conserved methods are only about 13%. Derivation of Case 2 result by mass weighted averaging method is up to 14.9%, which by the conserved methods is only about 5%. Results all show some deviation with equivalent one-dimensional result of multi-dimensional flow field, but the CMME and CMES methods fit better, and its computed thrusts are more reliable.