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Title: Enabling Advanced Modeling and Simulations for Fuel-Flexible Combustors

The overall goal of the present project is to enable advanced modeling and simulations for the design and optimization of fuel-flexible turbine combustors. For this purpose we use a high-fidelity, extensively-tested large-eddy simulation (LES) code and state-of-the-art models for premixed/partially-premixed turbulent combustion developed in the PI's group. In the frame of the present project, these techniques are applied, assessed, and improved for hydrogen enriched premixed and partially premixed gas-turbine combustion. Our innovative approaches include a completely consistent description of flame propagation, a coupled progress variable/level set method to resolve the detailed flame structure, and incorporation of thermal-diffusion (non-unity Lewis number) effects. In addition, we have developed a general flamelet-type transformation holding in the limits of both non-premixed and premixed burning. As a result, a model for partially premixed combustion has been derived. The coupled progress variable/level method and the general flamelet tranformation were validated by LES of a lean-premixed low-swirl burner that has been studied experimentally at Lawrence Berkeley National Laboratory. The model is extended to include the non-unity Lewis number effects, which play a critical role in fuel-flexible combustor with high hydrogen content fuel. More specifically, a two-scalar model for lean hydrogen and hydrogen-enriched combustion is developed and validatedmore » against experimental and direct numerical simulation (DNS) data. Results are presented to emphasize the importance of non-unity Lewis number effects in the lean-premixed low-swirl burner of interest in this project. The proposed model gives improved results, which shows that the inclusion of the non-unity Lewis number effects is essential for accurate prediction of the lean-premixed low-swirl flame.« less
Authors:
Publication Date:
OSTI Identifier:
1001422
DOE Contract Number:
FG26-08NT43325
Resource Type:
Technical Report
Research Org:
Leland Stanford Junior University
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; BURNERS; COMBUSTION; COMBUSTORS; DATA; DESIGN; FLAME PROPAGATION; FLAMES; FORECASTING; HYDROGEN; INCLUSIONS; LEWIS NUMBER; OPTIMIZATION; SIMULATION; THERMAL DIFFUSION; TRANSFORMATIONS; TURBINES