Characterization of complexities in combustion instability in a lean premixed gas-turbine model combustor

We present an experimental study on the nonlinear dynamics of combustion instability in a lean premixed gas-turbine model combustor with a swirl-stabilized turbulent flame. Intermittent combustion oscillations switching irregularly back and forth between burst and pseudo-periodic oscillations exhibit the deterministic nature of chaos. This is clearly demonstrated by considering two nonlinear forecasting methods: an extended version (Gotoda et al., 2015, “Nonlinear Forecasting of the Generalized Kuramoto-Sivashinsky Equation,” Int. J. Bifurcation Chaos, 25, p. 1530015) of the Sugihara and May algorithm (Sugihara and May, 1990, “Nonlinear Forecasting as a Way of Distinguishing Chaos From Measurement Error in Time Series,” Nature, 344, pp. 734–741) as a local predictor, and a generalized radial basis function (GRBF) network as a global predictor (Gotoda et al., 2012, “Characterization of Complexities in Combustion Instability in a Lean Premixed Gas-Turbine Model Combustor,” Chaos, 22, p. 043128; Gotoda et al., 2016 (unpublished)). The former enables us to extract the short-term predictability and long-term unpredictability of chaos, while the latter can produce surrogate data to test for determinism by a free-running approach. The permutation entropy based on a symbolic sequence approach is estimated for the surrogate data to test for determinism and is also used as an online detector to prevent lean blowout.

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F234 Effect of oxygen concentration on combustion instability in a lean premixed gas-turbine model combustor

The Proceedings of the Thermal Engineering Conference ◽

10.1299/jsmeted.2015._f234-1_ ◽

2015 ◽

Vol 2015 (0) ◽

pp. _F234-1_-_F234-2_

Author(s):

Satoshi KINOSHITA ◽

Kenta HAYASHI ◽

Hiroshi GOTODA

Keyword(s):

Gas Turbine ◽

Oxygen Concentration ◽

Combustion Instability ◽

Lean Premixed ◽

Effect Of Oxygen ◽

Turbine Model

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Extension of the Combustion Stability Range in Dry Low NOx Lean Premixed Gas Turbine Combustor Using a Fuel Rich Annular Pilot Burner

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4026186 ◽

2014 ◽

Vol 136 (5) ◽

Cited By ~ 5

Author(s):

L. Rosentsvit ◽

Y. Levy ◽

V. Erenburg ◽

V. Sherbaum ◽

V. Ovcharenko ◽

...

Keyword(s):

Gas Turbine ◽

Combustion Zone ◽

Combustion Instability ◽

Experimental Results ◽

Nox Emission ◽

Combustion Stability ◽

Stability Range ◽

Numerical Effort ◽

Lean Premixed ◽

Pilot Burner

The present work is concerned with improving combustion stability in lean premixed (LP) gas turbine combustors by injecting free radicals into the combustion zone. The work is a joint experimental and numerical effort aimed at investigating the feasibility of incorporating a circumferential pilot combustor, which operates under rich conditions and directs its radicals enriched exhaust gases into the main combustion zone as the means for stabilization. The investigation includes the development of a chemical reactors network (CRN) model that is based on perfectly stirred reactors modules and on preliminary CFD analysis as well as on testing the method on an experimental model under laboratory conditions. The study is based on the hypothesis that under lean combustion conditions, combustion instability is linked to local extinctions of the flame and consequently, there is a direct correlation between the limiting conditions affecting combustion instability and the lean blowout (LBO) limit of the flame. The experimental results demonstrated the potential reduction of the combustion chamber's LBO limit while maintaining overall NOx emission concentration values within the typical range of low NOx burners and its delicate dependence on the equivalence ratio of the ring pilot flame. A similar result was revealed through the developed CHEMKIN-PRO CRN model that was applied to find the LBO limits of the combined pilot burner and main combustor system, while monitoring the associated emissions. Hence, both the CRN model, and the experimental results, indicate that the radicals enriched ring jet is effective at stabilizing the LP flame, while keeping the NOx emission level within the characteristic range of low NOx combustors.

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Effects of superheated steam on combustion instability and NOx emissions in a model lean premixed gas turbine combustor

Fuel ◽

10.1016/j.fuel.2020.119646 ◽

2021 ◽

Vol 288 ◽

pp. 119646

Author(s):

Chengfei Tao ◽

Hao Zhou

Keyword(s):

Gas Turbine ◽

Superheated Steam ◽

Combustion Instability ◽

Nox Emissions ◽

Gas Turbine Combustor ◽

Lean Premixed

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Experimental and Numerical Characterization of Lean Hydrogen Combustion in a Premix Burner Prototype

Volume 2: Combustion, Fuels and Emissions, Parts A and B ◽

10.1115/gt2011-45623 ◽

2011 ◽

Cited By ~ 3

Author(s):

Iarno Brunetti ◽

Giovanni Riccio ◽

Nicola Rossi ◽

Alessandro Cappelletti ◽

Lucia Bonelli ◽

...

Keyword(s):

Natural Gas ◽

Gas Turbine ◽

Hydrogen Content ◽

Premixed Combustion ◽

Nox Emissions ◽

Cfd Model ◽

Air Velocity ◽

Lean Premixed Combustion ◽

Lean Premixed

The use of hydrogen as derived fuel for low emission gas turbine is a crucial issue of clean coal technology power plant based on IGCC (Integrated Gasification Combined Cycle) technology. Control of NOx emissions in gas turbines supplied by natural gas is effectively achieved by lean premixed combustion technology; conversely, its application to NOx emission reduction in high hydrogen content fuels is not a reliable practice yet. Since the hydrogen premixed flame is featured by considerably higher flame speed than natural gas, very high air velocity values are required to prevent flash-back phenomena, with obvious negative repercussions on combustor pressure drop. In this context, the characterization of hydrogen lean premixed combustion via experimental and modeling analysis has a special interest for the development of hydrogen low NOx combustors. This paper describes the experimental and numerical investigations carried-out on a lean premixed burner prototype supplied by methane-hydrogen mixture with an hydrogen content up to 100%. The experimental activities were performed with the aim to collect practical data about the effect of the hydrogen content in the fuel on combustion parameters as: air velocity flash-back limit, heat release distribution, NOx emissions. This preliminary data set represents the starting point for a more ambitious project which foresees the upgrading of the hydrogen gas turbine combustor installed by ENEL in Fusina (Italy). The same data will be used also for building a computational fluid dynamic (CFD) model usable for assisting the design of the upgraded combustor. Starting from an existing heavy-duty gas turbine burner, a burner prototype was designed by means of CFD modeling and hot-wire measurements. The geometry of the new premixer was defined in order to control turbulent phenomena that could promote the flame moving-back into the duct, to increase the premixer outlet velocity and to produce a stable central recirculation zone in front of the burner. The burner prototype was then investigated during a test campaign performed at the ENEL’s TAO test facility in Livorno (Italy) which allows combustion test at atmospheric pressure with application of optical diagnostic techniques. In-flame temperature profiles, pollutant emissions and OH* chemiluminescence were measured over a wide range of the main operating parameters for three fuels with different hydrogen content (0, 75% and 100% by vol.). Flame control on burner prototype fired by pure hydrogen was achieved by managing both the premixing degree and the air discharge velocity, affecting the NOx emissions and combustor pressure losses respectively. A CFD model of the above-mentioned combustion test rig was developed with the aim to validate the model prediction capabilities and to help the experimental data analysis. Detailed simulations, performed by a CFD 3-D RANS commercial code, were focused on air/fuel mixing process, temperature field, flame position and NOx emission estimation.

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