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

2014 ◽  
Vol 136 (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.

Development of a Natural Gas-Fired, Ultra-Low NOx Can Combustor for an 800 KW Gas Turbine

1991 ◽  
Author(s):  
K. O. Smith ◽  
A. C. Holsapple ◽  
H. K. Mak ◽  
L. Watkins
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Premixed Combustion ◽  
Experimental Results ◽  
Nox Emissions ◽  
Variable Geometry ◽  
Lean Premixed Combustion ◽  
Full Load ◽  
Primary Zone ◽  
Lean Premixed

The experimental results from the rig testing of an ultra-low NOx, natural gas-fired combustor for an 800 to 1000 kw gas turbine are presented. The combustor employed lean-premixed combustion to reduce NOx emissions and variable geometry to extend the range over which low emissions were obtained. Testing was conducted using natural gas and methanol. Testing at combustor pressures up to 6 atmospheres showed that ultra-low NOx emissions could be achieved from full load down to approximately 70% load through the combination of lean-premixed combustion and variable primary zone airflow.

Reactor Network Modeling of Stability and Emissions of Hydrogen and Natural Gas Blends for a Piloted Gas Turbine Combustor

2020 ◽  
Author(s):  
Candy Hernandez ◽  
Vincent McDonell
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Chemical Reactor ◽  
Experimental Results ◽  
Fuel Composition ◽  
Gas Turbine Combustor ◽  
Flammability Limits ◽  
Lean Premixed ◽  
Carbon Molecules

Abstract Lean-premixed (LPM) gas turbines have been developed for stationary power generation in efforts to reduce emissions due to strict air quality standards. Lean-premixed operation is beneficial as it reduces combustor temperatures, thus decreasing NOx formation and unburned hydrocarbons. However, tradeoffs occur between system performance and turbine emissions. Efforts to minimize tradeoffs between stability and emissions include the addition of hydrogen to natural gas, a common fuel used in stationary gas turbines. The addition of hydrogen is promising for both increasing combustor stability and further reducing emissions because of its wide flammability limits allowing for lower temperature operation, and lack of carbon molecules. Other efforts to increase gas turbine stability include the usage of a non-lean pilot flame to assist in stabilizing the main flame. By varying fuel composition for both the main and piloted flows of a gas turbine combustor, the effect of hydrogen addition on performance and emissions can be systematically evaluated. In the present work, computational fluid dynamics (CFD) and chemical reactor networks (CRN) are created to evaluate stability (LBO) and emissions of a gas turbine combustor by utilizing fuel and flow rate conditions from former hydrogen and natural gas experimental results. With CFD and CRN analysis, the optimization of parameters between fuel composition and main/pilot flow splits can provide feedback for minimizing pollutants while increasing stability limits. The results from both the gas turbine model and former experimental results can guide future gas turbine operation and design.

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

2012 ◽  
Vol 22 (4) ◽  
pp. 043128 ◽  
Author(s):  
Hiroshi Gotoda ◽  
Masahito Amano ◽  
Takaya Miyano ◽  
Takuya Ikawa ◽  
Koshiro Maki ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Combustion Instability ◽  
Lean Premixed ◽  
Turbine Model

Dynamic properties of combustion instability in a lean premixed gas-turbine combustor

2011 ◽  
Vol 21 (1) ◽  
pp. 013124 ◽  
Author(s):  
Hiroshi Gotoda ◽  
Hiroyuki Nikimoto ◽  
Takaya Miyano ◽  
Shigeru Tachibana
Keyword(s):  
Gas Turbine ◽  
Dynamic Properties ◽  
Combustion Instability ◽  
Gas Turbine Combustor ◽  
Lean Premixed

Dynamical Properties of Combustion Instability in a Laboratory-Scale Gas-Turbine Model Combustor

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
Hiroshi Gotoda ◽  
Kenta Hayashi ◽  
Ryosuke Tsujimoto ◽  
Shohei Domen ◽  
Shigeru Tachibana
Keyword(s):  
Gas Turbine ◽  
Combustion Instability ◽  
Turbulent Flame ◽  
Surrogate Data ◽  
Permutation Entropy ◽  
Lean Blowout ◽  
Lean Premixed ◽  
Free Running ◽  
Nonlinear Forecasting ◽  
Turbine Model

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.

Investigation of Tangential Trapped Vortex Combustor

2009 ◽  
Author(s):  
Chi Zhang ◽  
Yuzhen Lin ◽  
Quanhong Xu ◽  
Gaoen Liu
Keyword(s):  
Gas Turbine ◽  
Swirling Flow ◽  
Tangential Direction ◽  
Combustion Efficiency ◽  
Combustion Stability ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Stability Range ◽  
Combustion Technology ◽  
Trapped Vortex

An innovative concept of Tangential Trapped Vortex Combustor (TTVC) applying a swirling flow to eliminate the guide vanes of the compressor and turbine in the future gas turbine engines is presented via theoretical analysis and experimental investigation. In TTVC, the airflow is mostly whirlblast, and the processes of evaporation, mixing, and chemical reaction for the liquid spray combustion take place along the tangential direction. It is shown that the TTVC operation has the potential of improving combustion efficiency, widening combustion stability range, and reducing emissions, mainly due to the effects of trapped vortex, high centrifugal force, and periodical mixing. Experimental results of the ignition and LBO limits in a small 4-cup annular TTVC operating at atmospheric pressure demonstrated that this innovative combustion technology has a good LBO limit performance to meet the requirements of advanced gas turbine engines.

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