The use of OH* and CH* as heat release markers in combustion dynamics

Sardeshmukh, Swanand V.; Bedard, Michael; Anderson, William E.

doi:10.1177/1756827717718483

Cited by 69 publications

(17 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The OH is generated in a zone where extremely exothermic chemical reactions are taking place. As a result, the chemical kinetics of OH in a combustion event allows researchers to incarnate the flame front using the OH generation [18]. Figure 7 depicts the computed values from the flamelet library of OH and temperature profiles.…”

Section: Predicted Flame Frontmentioning

confidence: 99%

Reacting Flow Characteristics and Multifuel Capabilities of a Multi-Nozzle Dry Low NOx Combustor: A Numerical Analysis

Rahman

Yasin

Aris

2021

CFDL

View full text Add to dashboard Cite

The fluctuating quality of natural gas (NG) in Peninsular Malaysia (PM) makes it challenging for the gas turbine (GT) combustor to meet the combustion performance requirements from the Original Equipment Manufacturer (OEM). Moreover, the gas quality sensitivity is more apparent in modern dry low NOx (DLN) combustors. Many of the prior combustion investigations were conducted on a modest scale in the laboratory. In actuality, combustion characterizations in complicated DLN combustors are more valuable to the power generation sector. Hence, the current numerical analysis utilized the RANS formulation and a detailed chemistry to examine the impact of ethane (C2H6), carbon dioxide (CO2), and nitrogen (N2) proportions in NG on combustion characteristics in a multi-nozzle DLN (MN-DLN) combustor, with the support of Modified Wobbe Index (MWI) calculations. Validations were performed using the combustor outlet temperature (COT) from the power plant where the actual MN-DLN combustor is operated, which revealed less than 10 % discrepancy. Qualitative validations were carried out by comparing the burn trace from the actual combustor wall to the predicted results, revealing an adequate Structural Similarity Index (SSIM) of 0.43. From numerical results of flame fronts and COTs, the addition of 20 % diluents (CO2 and N2) to NG demonstrated the blowoff risk. When MWIs of Kerteh and the JDA (major NG resources) were used as baselines, MWI ranges of all NG compositions under study surpassed the OEM’s ± 5 % limit. The increase in CO2 proportion results in a wide MWI range, especially when Kerteh is used as the baseline. Therefore, any GTs in PM that have previously been calibrated to use Kerteh's NG are more likely to have combustion instabilities if CO2 levels in NG suddenly increase. The higher MWI range backs up the current numerical results that showed the deleterious effects of a high CO2 composition throughout the combustor firing process. However, increasing the amount of C2H6 by up to 20 % is predicted to have minor effects on combustion characteristics. Overall, the validated numerical model of the MN-DLN combustor provided critical information about combustion characteristics and multifuel capabilities in respect to the NG quality in PM.

show abstract

Section: Predicted Flame Frontmentioning

confidence: 99%

Reacting Flow Characteristics and Multifuel Capabilities of a Multi-Nozzle Dry Low NOx Combustor: A Numerical Analysis

Rahman

Yasin

Aris

2021

CFDL

View full text Add to dashboard Cite

show abstract

“…The Continuously Variable Resonant Combustor (CVRC) is a single element combustor with a gas-gas coaxial injector that is capable of exhibiting self-excited longitudinal instabilities and has been used as a benchmark case for model validation. 11,[43][44][45] The schematic of the CVRC is shown in Figure 3. The CVRC has a variable-length oxidizer post which can be adjusted by using the electro-mechanical actuator connected to the inlet of the oxidizer post.…”

Section: Application To the Continuously Variable Resonant Combustormentioning

confidence: 99%

Combustion instability modeling using multi-mode flame transfer functions and a nonlinear Euler solver

Tamanampudi

Sardeshmukh

Anderson

et al. 2020

International Journal of Spray and Combustion Dynamics

Self Cite

View full text Add to dashboard Cite

Modern methods for predicting combustion dynamics in high-pressure combustors range from high-fidelity simulations of sub-scale model combustors, mostly for validation purposes or detailed investigations of physics, to linearized, acoustics-based analysis of full-scale practical combustors. Whereas the high-fidelity simulations presumably capture the detailed physics of mixing and heat addition, computational requirements preclude their application for practical design analysis. The linear models that are used during design typically use flame transfer functions that relate the unsteady heat addition [Formula: see text] to oscillations in velocity and pressure ([Formula: see text] and [Formula: see text]) that are obtained from the wave equation. These flame transfer functions can be empirically determined from measurements or derived from theory and analysis. This paper describes a hybrid approach that uses high-fidelity simulations to generate flame transfer functions along with nonlinear Euler CFD to predict the combustor flowfield. A model rocket combustor that presented a self-excited combustion instability with pressure oscillations on the order of 10% of mean pressure is used for demonstration. Spatially distributed flame transfer functions are extracted from a high-fidelity simulation of the combustor and then used in a nonlinear Euler CFD model of the combustor to verify the approach. It is shown that the reduced-fidelity model can reproduce the unsteady behavior of the single element combustor that was both measured in the experiment and predicted by a high-fidelity simulation reasonably well.

show abstract

“…For the purposes of this work, the change in chemiluminescence intensity is assumed to be proportional to the heat release rate from the flame. 46–48 Line-of-sight integrated CH* chemiluminescence images are recorded at 75 kHz through a window in one side of the combustion chamber. The field-of-view (FOV), indicated in Figure 1, is 82 mm in the x -direction and 77 mm in the y -direction.…”

Section: Experiments Descriptionmentioning

confidence: 99%

Injector-coupled transverse instabilities in a multi-element premixed combustor

Philo

Gejji

Slabaugh

2020

International Journal of Spray and Combustion Dynamics

View full text Add to dashboard Cite

Combustion instabilities in a high-pressure, multi-element combustor are studied in order to understand the relationship between the chamber and injector dynamics. A linear array of seven injectors supplies premixed natural gas and air into a rectangular combustion chamber designed to promote high-frequency, transverse thermoacoustic instabilities. The effect of equivalence ratio on the combustion dynamics was investigated for two injector lengths, 62.5 and 125 mm. For all operating conditions, the 125 mm injectors promote high-amplitude instabilities of the fundamental transverse (1T) mode, which has a frequency of 1750–1850 Hz. Reducing the injector length significantly lowers the instability amplitudes for all operating conditions and, for lower equivalence ratio cases, excites an additional mode near 1550 Hz. The delineating feature controlling the growth of the instabilities in each injector configuration is the coupling with axial pressure fluctuations in the injectors that occur in response to the transverse modes in the chamber.

show abstract

The use of OH* and CH* as heat release markers in combustion dynamics

Cited by 69 publications

References 41 publications

Reacting Flow Characteristics and Multifuel Capabilities of a Multi-Nozzle Dry Low NOx Combustor: A Numerical Analysis

Reacting Flow Characteristics and Multifuel Capabilities of a Multi-Nozzle Dry Low NOx Combustor: A Numerical Analysis

Combustion instability modeling using multi-mode flame transfer functions and a nonlinear Euler solver

Injector-coupled transverse instabilities in a multi-element premixed combustor

Contact Info

Product

Resources

About