Evaluation of CH{sub 4}/NO{sub x} reduced mechanisms used for modeling lean premixed turbulent combustion of natural gas

Journal Article · Thu Oct 01 04:00:00 EDT 1998 · Journal of Engineering for Gas Turbines and Power

DOI:https://doi.org/10.1115/1.2818457· OSTI ID:316141

Mallampalli, H P; Fletcher, T H ^[1]; Chen, J Y ^[2]

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1. Brigham Young Univ., Provo, UT (United States). Chemical Engineering Dept.
2. Univ. of California, Berkeley, CA (United States). Mechanical Engineering Dept.

This study has identified useful reduced kinetic schemes that can be used in comprehensive multidimensional gas-turbine combustor models. Reduced mechanisms lessen computational cost and possess the capability to accurately predict the overall flame structure, including gas temperatures and key intermediate species such as CH{sub 4}, CO, and NO{sub x}. In this study, four new global mechanisms with five, six, seven, and nine steps based on the full GRI 2.11 mechanism, were developed and evaluated for their potential to model natural gas chemistry (including NO{sub x} chemistry) in gas turbine combustors. These new reduced mechanisms were optimized to model the high pressure and fuel-lean conditions found in gas turbines operating in the lean premixed mode. Based on perfectly stirred reactor (PSR) and premixed code calculations, the five-step reduced mechanism was identified as a promising model that can be used in a multidimensional gas-turbine code for modeling lean-premixed, high-pressure turbulent combustion of natural gas. Predictions of temperature, CO, CH{sub 4}, and NO from the five- to nine-step reduced mechanisms agree within 5% of the predictions from the full kinetic model for 1 < pressure (atm) < 30, and 0.6 < {phi} < 1.0. If computational costs due to additional global steps are not severe, the newly developed nine step global mechanism, which is a little more accurate and provided the least convergence problems, can be used. Future experimental research in gas turbine combustion will provide more accurate data, which will allow the formulation of better full and reduced mechanisms. Also, improvement in computational approaches and capabilities will allow the use of reduced mechanisms with larger global steps, perhaps full mechanisms.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FC21-92MC29061
• OSTI ID: 316141
• Journal Information: Journal of Engineering for Gas Turbines and Power, Journal Name: Journal of Engineering for Gas Turbines and Power Journal Issue: 4 Vol. 120; ISSN JETPEZ; ISSN 0742-4795
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
33 ADVANCED PROPULSION SYSTEMS
COMBUSTION
COMBUSTORS
COMPUTERIZED SIMULATION
GAS TURBINES
MATHEMATICAL MODELS
NATURAL GAS