Analysis of Turbulent Combustion Characteristic of Single Rocket Combustor with Shear-coaxial GH2/GO2 Injector.

摘要

In this study, to develop a robust and efficient code that can be applied to the rocket injector design technique, high resolution turbulent combustion flow analysis of a combustor using a gas hydrogen / gas oxygen single coaxial shear injector according to a reaction mechanisms was performed.rnThe compressible Navier-Stokes equations are used as the governing equations in the two-dimensional coordinate system for the analysis, and the DES model, which extends Menter's SST model among the hybrid RANS / LES, is used as the turbulence model. The AUSMDV was used for the numerical flux method and the 5th oMLP was used for the higher order spatial difference method. In order to investigate the turbulent combustion characteristics according to the reaction mechanism and the grid resolution, the reduced(7 Step), detail(Jachimowski), and pressure dependent(UCSD, USC) mechanisms were applied, and the grid level of the main combustor was set at about 40,000 to 360,000.rnAt the result of OH Mass Fraction(yOH), all mechanisms, the tendency of the combustion reaction to occur actively as the downstream of the combustor was found to be the same, but the reduced mechanism over predicted near the injector and upstream of the combustor. This was also predicted in result of Mixture Ratio(fmix). As a result of the scalar dissipation rate and flame index, the flame structure near the injector and the premixed or diffusive combustion characteristics of the entire combustor can be analyzed. Finally, the scattered plots showing the relation between flame index, OH mass fraction and mixture fraction showed that the diffusive-comb characteristics are more evident when the OH mass fraction value increases in the relatively low mixture fraction value distribution.