| In this paper, a computer code with various mathematical models is developed to simulate three-dimensional two-phase reacting flowfield as well as combustion performance for three different annual combustors, including two-stage radial swirler annual combustor, two cylindrical head annual combustor and reverse-flow annual combustor with a diffuser, swirler cup, annular linner and two cooling passages and transition duct in arbitrary curvilinear coordinates. The integrated grids of combustor are generated by the method of TTM with the grid obstacle method for the complex geometric configuration. In order to model the complicated interactions between the gas and liquid phase, a Lagrangian-Eulerian two-phase flow prediction algorithm is adopted in which the gas phase is calculated in an Eulerian frame of reference whilst a separate calculation is performed for the liquid phase in a Lagrangian frame of reference. In this code, the k-ε, RNG k-εand ASM turbulent models are respectively used for turbulence modeling, EBU-Arrhenius, SOM-EBU and extended EBU-Arrhenius turbulent combustion models are adopted to determine the rate of reaction. The six-flux and discrete-ordinate (DO) radiation models are used to predict the radiant heat transfer in combustion chambers. The particle trajectory model and stochastic particle trajectory model are applied to simulation the droplet trajectories,size and temperature history. Four-step chemical reaction mechanisms combined with pollution formation models are used to estimate pollutant emission.In arbitrary curvilinear coordinates, the expressions of ASM turbulent model and DO radiation model are derivated here. A extended EBU-Arrhenius model,considering influence of the reaction scale and the turbulence scale on the reaction rate,is presented for more accurate calculation gas temperature distributions. Base temperature variation rate of recirculation zone, the fuel step-by-step method is presented to estimate the lean blowout of annular combustors.The Hybrid or QUICK difference schemes over the control volume are used to obtain the finite difference equaeions. On the non-staggered grid system, the discretization equations are solved with SIMPLE or PISO algorithm, and the couple of the gas and the liquid phase is carried out by the PSIC method. Above models and methods are integrated in the visualization program for researching reverse flow type conbustor.The influences of various mathematical models on two-phase combustion integrated flow fields in annular combustors are predicted. Predictions are in reasonable agreement with the measurements and it indicates that the k-εand RNG k-εturbulent models are more appropriate to engneering applications. Extended EBU-Arrhenius turbulent combustion model is more reasonable for modeling turbulent reacting flows. SOM-EBU combustion model taking account of the enflence of fluctuation parameters on the reaction rate,is better than EBU-Arrhenius model,and computing time and storge of SOM-EBU model is more than it. DO radiation models,which may be predicted the effect of the dicretion direction and scattering phase on the radiative transfer,is better than Six-flux model and is more applicable for two-phase reacting flows of the annual combustors.The cold flow fields in a sector annual combustor with dual-stage radial swirler are measured by Laser Doppler Velocimeter (LDV). The measured and calculated axial velocity profiles are in general agreement.The performance of the reverse-flow annual combustor is studied with numerical models to consider the distribution of the pollution production. Comparing with experiment data of profiles of outlet gas temperature and lean blowout limit for two cylindrical head annual combustor and the reverse-flow annual combustor,predictions are reasonable. So, it reveals that the numerical procedures are reliable and useable in the design of the annual combustor.
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