CFD Simulation of Noise in Gas Turbine Combustors by Means of Turbulence Refluctuation Method

2008 ◽  
Author(s):  
Stefano Tiribuzi
Keyword(s):  
Gas Turbine ◽  
Local Level ◽  
Computing Time ◽  
Combustion Noise ◽  
Qualitative Description ◽  
Combustion Stability ◽  
Medium Size ◽  
Pure Hydrogen ◽  
Computational Domain ◽  
Gas Turbine Combustors

The paper describes a numerical simulation methodology based on CFD for deriving and analyzing the spectral and spatial characteristics of combustion noise in industrial gas turbine combustors. ENEL is testing the combustion section of a medium size pure hydrogen-fed gas turbine, during which pressure fluctuation levels are also measured to asses the combustion stability. Pressure probes are located in colder zones only, but information on the fluctuations levels throughout the whole component are also desired. For this purpose, a simple empirical and, to the knowledge of the author, original method, based solely on CFD modelling, was developed for reproducing in a realistic way the spatial and transient characteristics of the acoustic flow field inside the combustor volumes. The method employs a sparse and persistent excitation on a wide frequency spectrum, by imposing a stochastic fluctuating component to the velocity computed on each grid node throughout the entire computational domain. The intensity of this additional component is proportional to the local level of the modelled turbulent velocity, so the method will be shortly designated as PRMT (Partial Refluctuation of Modelled Turbulence). This method requires that all the acoustically connected volumes be included in the computational domain and that transients be protracted for a time sufficient to provide meaningful spectral information. KIEN, an in-house low diffusive URANS code capable of simulating 3D reactive flows, was used. The adopted Very Rough Grid approach made it possible to protract the simulated transient for a long time, with an affordable computing time. Comparison with in-plant measured data shows that the refluctuation method provides a realistic qualitative description of the noise spectrum. The spatial distribution of computed acoustic field is also derived and analyzed.

scholarly journals Experimental investigation of entropy waves’ evolution for understanding of indirect combustion noise in gas turbine combustors

Energy ◽  
2020 ◽  
Vol 195 ◽  
pp. 116978 ◽  
Author(s):  
S.M. Hosseinalipour ◽  
A. Fattahi ◽  
H. Khalili ◽  
F. Tootoonchian ◽  
N. Karimi
Keyword(s):  
Experimental Investigation ◽  
Gas Turbine ◽  
Combustion Noise ◽  
Gas Turbine Combustors

Experimental Analysis of Confinement and Swirl Effects on Premixed CH4-H2 Flame Behavior in a Pressurized Generic Swirl Burner

2017 ◽  
Author(s):  
Jon Runyon ◽  
Richard Marsh ◽  
Daniel Pugh ◽  
Philip Bowen ◽  
Anthony Giles ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Kinetic Modelling ◽  
Dynamic Pressure ◽  
Flame Stabilization ◽  
Combustion Noise ◽  
Combustion Stability ◽  
Acoustic Response ◽  
Swirl Burner ◽  
Swirl Number

The introduction of hydrogen into natural gas systems for environmental benefit presents potential operational issues for gas turbine combustion and power generation applications; in particular acceptable blending concentrations are still widely debated. The use of a generic swirl burner under conditions pertinent to a gas turbine combustor is therefore advantageous to (i) provide evidence of potential design modifications to inform future gas turbine operation on hydrogen blends and (ii) validate numerical model predictions. Building on a previous experimental combustion database consisting of methane-hydrogen fuel blends under atmospheric and elevated ambient conditions, a new scaled generic swirl burner has been designed for experimental investigation of flame stability and exhaust gas emissions at combustor inlet temperatures to 573 K, pressures to 0.33 MPa, and thermal powers to 126 kW. The geometry downstream of the modular burner is developed further to enable separate investigation under isothermal and combustion conditions of the influence of combustor outlet geometry and the effect of changing geometric swirl number. The burner confinement is modified to include both a cylindrical exit quartz combustion chamber and a conical convergent exit quartz combustion chamber, designed to provide a more representative geometric and acoustic boundary at the combustor outlet. Two inlet geometric swirl numbers of industrial relevance are chosen; namely 0.5 and 0.8. Combustion stability and heat release locations of lean premixed CH4-air and CH4-H2-air combustion are evaluated by a combination of OH planar laser induced fluorescence, OH* chemiluminescence, and dynamic pressure measurements. Changes in flame stabilization location are characterized by the use of an OH* chemiluminescence intensity centroid. Notable upstream flame movement coupled with changes in acoustic response are evident, particularly near the lean operating limit as hydrogen blending shifts lean blowoff of methane flames to lower equivalence ratios with corresponding reduction in NOx emissions. The influence of increased pressure on the lean operating point stability and emissions appear to be small over the range considered, however a power law correlation has been developed for scaling combustion noise amplitudes with inlet pressure and swirl number. Indicators of flame flashback as well as combustor acoustic response are affected considerably when the convergent combustor outlet geometry is deployed. This has been shown to alter the influence of the central recirculation zone as a flame stabilizing coherent flow structure. Chemical kinetic modelling supports the experimental observations that stable burner operation can be achieved with blended methane-hydrogen up to 15% by volume.

scholarly journals Thermoacoustic Instability Considerations for High Hydrogen Combustion in Lean Premixed Gas Turbine Combustors: A Review

Hydrogen ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 33-57
Author(s):  
Jadeed Beita ◽  
Midhat Talibi ◽  
Suresh Sadasivuni ◽  
Ramanarayanan Balachandran
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Hydrogen Combustion ◽  
Dynamic State ◽  
Pure Hydrogen ◽  
High Hydrogen ◽  
Combustion Dynamics ◽  
Thermoacoustic Instability ◽  
Gas Turbine Combustors ◽  
Lean Premixed

Hydrogen is receiving increasing attention as a versatile energy vector to help accelerate the transition to a decarbonised energy future. Gas turbines will continue to play a critical role in providing grid stability and resilience in future low-carbon power systems; however, it is recognised that this role is contingent upon achieving increased thermal efficiencies and the ability to operate on carbon-neutral fuels such as hydrogen. An important consideration in the development of gas turbine combustors capable of operating with pure hydrogen or hydrogen-enriched natural gas are the significant changes in thermoacoustic instability characteristics associated with burning these fuels. This article provides a review of the effects of burning hydrogen on combustion dynamics with focus on swirl-stabilised lean-premixed combustors. Experimental and numerical evidence suggests hydrogen can have either a stabilising or destabilising impact on the dynamic state of a combustor through its influence particularly on flame structure and flame position. Other operational considerations such as the effect of elevated pressure and piloting on combustion dynamics as well as recent developments in micromix burner technology for 100% hydrogen combustion have also been discussed. The insights provided in this review will aid the development of instability mitigation strategies for high hydrogen combustion.

Factors Determining the Flame Configuration and Affecting Combustion Stability in Gas-Turbine Combustors

2020 ◽  
Vol 54 (4) ◽  
pp. 537-540
Author(s):  
L. A. Bulysova ◽  
A. G. Tumanovskii ◽  
M. N. Gutnik ◽  
V. D. Vasil’ev
Keyword(s):  
Gas Turbine ◽  
Combustion Stability ◽  
Gas Turbine Combustors

scholarly journals Combustion Generated Noise in Gas Turbine Combustors

1976 ◽  
Vol 98 (2) ◽  
pp. 242-246 ◽  
Author(s):  
W. C. Strahle ◽  
B. N. Shivashankara
Keyword(s):  
Gas Turbine ◽  
Sound Absorption ◽  
Combustion Noise ◽  
Noise Power ◽  
Gas Turbine Combustor ◽  
Gas Turbine Combustors ◽  
Air Flows

Experiments are conducted for the noise power and spectra emitted from a gas turbine combustor can exhausting to the atmosphere. The theory of combustion noise is applied to the results to determine the noise generating capability of the flame in the absence of reflecting can surfaces. The results show that for a fixed fuel (JP-4) the noise output is independent of fuel/air ratio for well stabilized can-type flames and heavily dependent on airflow while the spectra are dominated by the can acoustics, primarily through sound absorption by the liner. In an installed configuration the noise output depends heavily on the enclosure acoustics. For well stabilized can-type flames the equivalent unenclosed flame radiates with a thermoacoustic efficiency near 5 × 10−6, for air-flows of the magnitude used in this program. Scaling rules are presented for installed configurations.

scholarly journals Entropy and Vorticity Wave Generation in Realistic Gas Turbine Combustors

2019 ◽  
Vol 35 (4) ◽  
pp. 839-849 ◽  
Author(s):  
Bernhard Semlitsch ◽  
Tom Hynes ◽  
Ivan Langella ◽  
Nedunchezhian Swaminathan ◽  
Ann P. Dowling
Keyword(s):  
Gas Turbine ◽  
Wave Generation ◽  
Gas Turbine Combustors

scholarly journals Fully Coupled Large Eddy Simulation of Conjugate Heat Transfer in a Ribbed Channel with a 0.1 Blockage Ratio

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2096
Author(s):  
Joon Ahn ◽  
Jeong Chul Song ◽  
Joon Sik Lee
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Conjugate Heat Transfer ◽  
Heat Transfer Analysis ◽  
Scale Model ◽  
Computational Domain ◽  
Blockage Ratio ◽  
Ribbed Channel ◽  
Large Eddy ◽  
Cooling Passage

Large eddy simulations are performed to analyze the conjugate heat transfer of turbulent flow in a ribbed channel with a heat-conducting solid wall. An immersed boundary method (IBM) is used to determine the effect of heat transfer in the solid region on that in the fluid region in a unitary computational domain. To satisfy the continuity of the heat flux at the solid–fluid interface, effective conductivity is introduced. By applying the IBM, it is possible to fully couple the convection on the fluid side and the conduction inside the solid and use a dynamic subgrid scale model in a Cartesian grid. The blockage ratio (e/H) is set at 0.1, which is typical for gas turbine blades. Through conjugate heat transfer analysis, it is confirmed that the heat transfer peak in front of the rib occurs because of the impinging of the reattached flow and not the influence of the thermal boundary condition. When the rib turbulator acts as a fin, its efficiency and effectiveness are predicted to be 98.9% and 8.32, respectively. When considering conjugate heat transfer, the total heat transfer rate is reduced by 3% compared with that of the isothermal wall. The typical Biot number at the internal cooling passage of a gas turbine is <0.1, and the use of the rib height as the characteristic length better represents the heat transfer of the rib.

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