Assessment of Scale Adaptive Simulation Model for Honeywell Combustor

Abstract

The complex flow phenomena inside a gas turbine combustor demands alternative simulation methods to the Reynolds Averaged Navier-Stokes (RANS) model, where a portion of turbulence scales is resolved inside the flow domain. Large Eddy Simulation (LES) is the most-widely acknowledged method for its attractive feature of resolving large turbulent structures down to the grid limit for the entire flow domain. However, for practical industrial problems where the Reynolds number is high and the flow domain is large, the grid resolution for LES becomes excessively high making it computationally very expensive. Scale Adaptive Simulation (SAS), on the other hand, adjusts to the resolved structures in an Unsteady RANS (URANS) simulation resulting in LES-like behavior in unsteady regions of the flow field. At the same time, it provides RANS capabilities in the stable flow regions. It allows a larger time step than LES resulting in the possibility of computation time advantage with LES-like solution fidelity. In the current paper, the SAS model is compared to the LES model for a Honeywell combustor using the commercial CFD code ANSYS FLUENT. Several time-steps are considered for SAS simulations. Results show that SAS is promising in terms of predicting combustor performance parameters like LES, but with a substantially reduced turn-around time.