Session: 04-04: Combustion Modeling I

Paper Number: 82291

82291 - Predicting Emissions Across Design Variations of an Aero-Engine Combustor Using FGM and PISO 

A modelling approach for quickly predicting CO and Unburned Hydrocarbon (UHC) emissions is assessed in Simcenter STAR-CCM+ version 2021.3. Both magnitude and trends are evaluated across design variations of an aero-engine test combustor operating at an idle condition. Large Eddy Simulation (LES) is used with the non-iterative Pressure Implicit by Splitting of Operators (PISO) scheme, and the Flamelet Generated Manifold (FGM) model. There are four geometric design variations of the same test combustor where changes are made to the dome effusion cooling, main swirler, and downstream orifices. These four geometries are chosen for this study because they yield distinctly different CO and UHC emissions, thus reducing signal to noise in assessing the predictive capability of the modelling approach. Sensitivity of the results to a key parameter in the liquid fuel spray breakup model is provided. By varying the breakup rate, the prediction of the CO emissions is shown to compare very favourably both in magnitude and trend to the experimentally measured values. The UHC emissions are shown to compare well for three of the four designs. Results are also generated using the Semi-Implicit Method for Pressure Linked Equations (SIMPLE) scheme and show the same behaviour as PISO. However, the results with PISO can be obtained up to 3X faster than the more traditional approach. Combining the computational efficiency of FGM and PISO allows for fast and accurate predictions of regulated emissions, and therefore down-selection of designs earlier in the design process.

Presenting Author: Megan Karalus Siemens Digital Industries

Presenting Author Biography: Megan Karalus is a Senior Application Engineer at Siemens Digital Industries, for Simcenter STAR-CCM+. For the past 8 years she has worked directly with customers in the energy and aerospace industries to develop their simulation methodologies for reacting flow applications. Prior to that she received a PhD in Mechanical Engineering from the University of Washington studying NOx emissions and lean blowout of lean-premixed combustion systems burning methane and hydrogen fuel mixtures.

Authors:

Megan Karalus Siemens Digital Industries
Dustin Brandt Honeywell Aerospace
Liam Mcmanus Siemens Digital Industries
Erik Munktell Siemens Digital Industries