Isothermal Flow Field Modelling of Gas Turbine Afterburners

A computational procedure is described for the calculation of three dimensional flow fields in a gas turbine afterburner. The computations are based on numerical solution of time-averaged transport equations for mass, momentum, turbulence kinetic energy and dissipation rate using a finite volume formulation. The calculations are performed using a SIMPLE type algorithm with non-staggered grid arrangement. Turbulence is modelled using the two-equation k - ε eddy viscosity model. The mean flow structures are presented in detail for important longitudinal and cross-sectional planes and the flame stabilizer flow is shown to be dominated by a complex combination of recirculation and vortex patterns. The effects of certain crucial design and operational parameters like inlet velocity profiles, radial gutter and diffuser have been studied which will be helpful to analyze a wide variety of flow situations in afterburners. These studies also prove the consistency and capability of the code to handle different situations.