Numerical Prediction For Lean Blowout Of Annular Combustion

The lean blowout of combustor is a most important standard for judging stablecombustion. Researching different influencing factor of gas-oil ratio about lean blowout canprovide reference for optimization design of gas turbine combustor.Firstly, the design and meshing of the geometry of the annular combustor calculationhave been done by Pro/e4.0and ANSYS ICEM, and then ANSYS FLUENT has been usedfor numerical simulation. Three different methods (fuel steady stepwise method, therecirculation zone flameout node velocity method and the feature-section-criterion (FSC)) hasbeen done is this paper. Then the compare between simulation results and experiment datahave been shown. The result shows that the predictions of fuel steady stepwise method andFSC are in agreement with corresponding experimental data. This part of the work establisheda stable foundation for subsequent work and finally fuel steady stepwise method was used forfurther numerical simulation.This paper compares the impact of the direction of rotation, structural parameters ofswirler, inlet air flow parameters and the average diameter on LBO. The results show that:(1)Reverse arrangement could increase the LBO than concurrent arrangement.(2) The flow areaand the angle of oblique hole could increase the lean blowout fuel-oil ratio; the angle ofoblique hole and secondary blade could decrease the fuel-oil ratio. The distances frombottleneck to outlet of venturi and diameter of venturi and fuel-oil ratio have no relationship.(3) Fuel-oil ratio will decrease with the increasing of the velocity.(4) When the averagediameter of droplet is from30μm to70μm, fuel-oil ratio almost has not changed. When theaverage diameter of droplet is from70μm to90μm, fuel-oil ratio increases quickly. When theaverage diameter of droplet is more than90μm, fuel-oil ratio decreases quickly.The method of prediction for LBO and the influence of the direction of rotation,structural parameters of swirler, inlet air flow parameters and the average diameter on LBOhave been confirmed. The results showed that this method for predicting lean blowout isreliable and can be used for engineering applications.