Flame volume prediction and validation for lean blow-out of gas turbine combustor

Ahmed, Ejaz; Huang, Yong

doi:10.1017/aer.2016.125

Cited by 14 publications

(9 citation statements)

References 45 publications

(60 reference statements)

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“…They conducted an experimental study in a gas turbine combustor and applied OH PLIF and POD to determine reasons for the frequency mode shift phenomenon (11) . Moreover, many researchers have studied the characteristics of combustion using experimental (12)(13)(14)(15)(16)(17)(18)(19)(20) , analytic (21,22) and computational (23)(24)(25) approaches.…”

Section: Past Research On H 2 /Ch 4 Combustion In Gas Turbinementioning

confidence: 99%

High-frequency transition characteristics of synthetic natural gas combustion in gas turbine

et al. 2019

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In this study, the combustion instability and emission characteristics of flames of different H2/CH4 compositions were investigated in a partially premixed model gas turbine combustor. A mode shift in the frequency of instability occurred under varying experimental conditions from the first to the seventh mode of longitudinal frequency in the combustor, and a parametric study was conducted to determine the reasons for this shift by using the length of the combustor, a factor that determines the mode frequency of longitudinal instability, as the main parameter. Furthermore, heat load and fuel composition (H2 ratio) were considered as parameters to compare the phenomenon under different conditions. The GRI-3.0 CANTERA code, OH chemiluminescence and the Abel inversion process were applied to analyse the frequency mode shift. NOx emissions, which occurred through the thermal NOx mechanism, increased with increasing heat load and H2 ratio. The instability frequency shifted from the first to the seventh mode as the H2 ratio increased in the H2/CH4 mixture. However, 100% H2 as fuel did not cause combustion instability because it has a higher burning velocity and extinction stretch rate than CH4. Furthermore, the laminar flame speed influenced the frequency mode shift. These phenomena were confirmed by the flame shapes. The Abel inversion process was applied to obtain the cross section of the flames from averaged OH chemiluminescence images. Stable and unstable flames were identified from the radial profile of OH concentration. The combustor length was found to not influence frequency mode shift, whereas the H2 ratio significantly influenced it as well as the flame shape. The results of this experimental study can help in the reliable operation of gas turbine systems in SNG plants.

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Section: Past Research On H 2 /Ch 4 Combustion In Gas Turbinementioning

confidence: 99%

High-frequency transition characteristics of synthetic natural gas combustion in gas turbine

et al. 2019

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“…The first idea to obtain the FV is by extracting some intermediate parameter in the non-reacting flow field and use correlations to calculate the FV [24][25]. The second idea to obtain the FV is by extracting the FV directly from the reacting flow field [26]. Critical temperature is selected as a criterion to determine the flame zone.…”

Section: The Semi-empirical Based Hybrid Prediction Methodsmentioning

confidence: 99%

On the Quick Prediction of Lean Blowout Limits for Gas Turbine Combustors

Huang¹,

Sun²

2018

dteees

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The lean blowout (LBO) limit plays a critical role in the operation of gas turbine combustors. In order to achieve the quick prediction of the LBO limit, three major prediction tools for the LBO limit, i.e. the semi-empirical correlation, the numerical prediction method and the hybrid prediction method are proposed. The semi-empirical correlations are mainly based on the characteristic time (CT) model and the perfect stirred reactor (PSR) model. The semi-empirical correlations based on the PSR model are widely applied. Among these correlations, Lefebvre's LBO model that had been validated on 8 different aero gas turbine combustors with the uncertainty ±30% is the most successful. Later, many researchers did further studies to improve Lefebvre's LBO model. The numerical prediction methods are reported increasingly with the rapid development of the computing power. Up to now, some researchers validated the numerical prediction methods in 2 different combustor configurations with the prediction uncertainties about ±25%. More studies are required to validate the effects of the combustor configurations and the atomization performances on the LBO limit. The hybrid prediction methods try to combine the semi-empirical correlations with the numerical methods and are widely attempted in recent years. Many researchers have studied the numerical based hybrid method, which needs more validations and general criterions for different configurations and operating conditions. Other researchers have studied the semi-empirical based hybrid method, which has shown good agreement for 11 different combustor configurations with the prediction uncertainties about ±16%. Further improvements are required for all prediction tools to achieve more general and accurate predictions for the LBO limits of gas turbine combustors.

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“…It has been validated on several combustors but the prediction accuracy is limited i.e., ±30. It has been proposed previously (15) that lower prediction accuracy is mainly ascribed to insufficient Prediction of lean blowout performance of gas… modelling in the 1 st term of Equation (1) i.e., the geometric term…”

Section: Introductionmentioning

confidence: 99%

“…The real challenge associated with this methodology is to identify and calculate V f in flow simulations. Fuel Iterative Approximation (FIA) methodology based on cold flow simulations (12) and hot flow simulations (15) has been carried out for (V f ) estimation and eventually for LBO prediction. In the proposed FIA iterative loop, each case/geometry must undergo at least 10 simulations until the LBO limit is achieved and a realistic prediction value is approached.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of lean blowout performance of gas turbine combustor based on flow structures

Ahmed

Huang

2017

Aeronaut. j.

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The insufficient depth of modelling to capture the flow physics within primary combustion zone is the prime reason behind limited accuracy of semi-empirical correlations. Flame volume concept establishes a better connection between LBO performance and flame parameters, which improves the modelling depth and hence the prediction accuracy. Nonetheless, estimation of flame parameters is a challenging task. In addition, the iterative loop to approach convergence for a single geometry demands several numerical simulation runs. In this study, the association of LBO performance has been extended to flow structures, they are uniquely associated with the geometric features and can efficiently relate global LBO performance with primary zone geometry. The lean blowout phenomenon was presented as a contest between igniting and extinction forces within Reverse Flow Zone. These forces were quantified by four performance parameters including area, minimum axial velocity, average temperature, and average velocity. Selected parameters provide valuable information regarding the size of recirculation bubble, the intensity of flow reversal and the amount of entrained hot gases. For the purpose of validation, 11 combustor geometries were selected. The RANS simulation was carried out to estimate performance parameters, and predicted performance was compared against experimental data. The excellent agreement highlights the efficiency and promising future for the proposed methodology. Moreover, the association of prediction process with flow structure, instead of geometric features/dimension, makes it universal prediction methodology for wide range of combustor configurations.

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Flame volume prediction and validation for lean blow-out of gas turbine combustor

Cited by 14 publications

References 45 publications

High-frequency transition characteristics of synthetic natural gas combustion in gas turbine

High-frequency transition characteristics of synthetic natural gas combustion in gas turbine

On the Quick Prediction of Lean Blowout Limits for Gas Turbine Combustors

Prediction of lean blowout performance of gas turbine combustor based on flow structures

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