A fully-elliptic three dimensional computational fluid dynamic (CFD) code based on pressure-correction techniques has been used in the design of an advanced turbine single annular reverse-flow combustor (AR1600) under development at Alfa Romeo Avio (ARA).
Fuel injection was handled using a Lagrangian liquid droplet spray model coupled to the gas phase equations, which are solved in an Eulerian frame of reference. Turbulent transport is described by the standard k-ε model. The combustion model utilizes a conserved scalar formulation and an assumed shape probability density function to account for chemistry-turbulence interaction.
The numerical algorithm employs structured nonorthogonal curvilinear grids, node-centered variable arrangement and Cartesian velocity components.
The code was validated on a similar combustor (AR318 turboprop engine of 600 SHP). The numerical results agree well with the test measurements available for this chamber.
The aerothermal design of AR1600 (1600K exit temperature) has the same gemetrical constraints of AR318 (tip and root diameters for compressor outlet and turbine inlet), but the lenght is shorter to reduce surface area for less cooling and to utilize the excess air for more efficient mixing and combustion.