A Numerical Study on Characteristics of Swirl Premixed Flame Interaction Affecting NO Emission in a Gas Turbine Combustor

2015 ◽  
Author(s):  
Junho Park ◽  
Cheon Hyeon Cho ◽  
Chae Hoon Sohn
Keyword(s):  
Gas Turbine ◽  
Numerical Study ◽  
Swirl Flow ◽  
Gas Turbine Combustor ◽  
No Emission ◽  
Step Size ◽  
No Formation ◽  
Air Stream ◽  
Swirl Flows ◽  
Model Chamber

Flame interaction between two neighboring burners in a gas turbine combustor is investigated numerically for pursuit of its effect on NOx emission from the burners. In a model chamber or liner, EV burners with double cone are installed. Two burners with the opposite rotating directions (L-R type burner) of air stream are adopted and the distance between them is variable from 74.2 mm to 222.6 mm by the step size of 37.1 mm and an additional distance of 171.3 mm is considered. Gaseous methane and air are adopted as fuel and oxidizer, respectively. From steady-state numerical analyses, flow, temperature, and NO concentration fields are calculated in all computational cases to find their correlation with NO formation. NO emission is evaluated at the exit of the model chamber with two burners as a function of burner distance. Swirl flows induced by EV burner are kept up to the liner exit, but with weaker swirl than that of the same rotating burners (L-L type burners). The case of shortest distance presents strong correlation between two flames while the other cases present weak correlation. In all cases of L-R type burners, NO emission is lower than that of L-L type burners, which results from change in swirl flow patterns. NO emission from L-R type burners with intermediate distances is greater than that from a single burner, but it is smaller than the latter with relatively shorter and longer burner distances.

Effects of Burner Interaction on NOx Emission From Swirl Premix Burner in a Gas Turbine Combustor

2014 ◽  
Author(s):  
Cheon Hyeon Cho ◽  
Chae Hoon Sohn ◽  
Ju Hyeong Cho ◽  
Han Seok Kim
Keyword(s):  
Gas Turbine ◽  
Nox Emission ◽  
Gas Turbine Combustor ◽  
Step Size ◽  
Flow Temperature ◽  
Nox Formation ◽  
Air Stream ◽  
Flow Interactions ◽  
Model Chamber ◽  
Wall Interaction

Flame interaction between neighboring burners in a gas turbine combustor is investigated numerically for pursuit of its effect on NOx emission from the burners. In a model chamber or liner, EV burners with double cone are installed. Two burners with the same rotating direction of air stream are adopted and the distance between them is variable from 74.2 mm to 222.6 mm by the step size of 37.1 mm. Gaseous methane and air are adopted as fuel and oxidizer, respectively. From steady-state numerical analyses, flow, temperature, and NO concentration fields are calculated in all computational cases to find their correlation with NOx formation. NOx emission is evaluated at the exit of the model chamber with two burners as a function of burner distance and compared with that from a single burner. In all cases of two-burner calculations, NOx emission is higher than that of a single burner, which results from flow interactions between neighboring burners as well as between a burner and a liner wall. NOx emission is affected significantly by flow and flame interactions between them and strongly depends on burner distance. Burner interaction is divided into two regimes of a burner-burner interaction and a burner-wall interaction depending on the distance. In the former regime, NOx emission is reduced as flame interaction between burners is enhanced and in the latter regime, it is also reduced as interaction between the burner and the liner wall is enhanced.

Experimental and numerical study of flame structure and emissions in a micro gas turbine combustor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vedant Dwivedi ◽  
Srikanth Hari ◽  
S. M. Kumaran ◽  
B. V. S. S. S. Prasad ◽  
Vasudevan Raghavan
Keyword(s):  
Gas Turbine ◽  
Rural Areas ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
Numerical Study ◽  
Operating Conditions ◽  
Emission Characteristics ◽  
Nitric Oxides ◽  
Gas Turbine Combustor ◽  
Micro Gas Turbine

Abstract Experimental and numerical study of flame and emission characteristics in a tubular micro gas turbine combustor is reported. Micro gas turbines are used for distributed power (DP) generation using alternative fuels in rural areas. The combustion and emission characteristics from the combustor have to be studied for proper design using different fuel types. In this study methane, representing fossil natural gas, and biogas, a renewable fuel that is a mixture of methane and carbon-dioxide, are used. Primary air flow (with swirl component) and secondary aeration have been varied. Experiments have been conducted to measure the exit temperatures. Turbulent reactive flow model is used to simulate the methane and biogas flames. Numerical results are validated against the experimental data. Parametric studies to reveal the effects of primary flow, secondary flow and swirl have been conducted and results are systematically presented. An analysis of nitric-oxides emission for different fuels and operating conditions has been presented subsequently.

Effect of Prediffuser Angle on the Static Pressure Recovery in Flow Through Casing-Liner Annulus of a Gas Turbine Combustor at Various Swirl Levels

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Prakash Ghose ◽  
Amitava Datta ◽  
Achintya Mukhopadhyay
Keyword(s):  
Gas Turbine ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Recovery ◽  
Gas Turbine Combustor ◽  
Pressure Losses ◽  
Pressure Distributions ◽  
Inlet Swirl ◽  
Flow Through ◽  
The Ideal

A numerical study has been performed in an axisymmetric diffuser followed by a casing-liner annulus of a typical gas turbine combustor to analyze the flow structure and pressure recovery in the geometry. Static pressure recovery in a gas turbine combustor is important to ensure high pressure of air around the liner. However, the irreversible pressure losses reduce the static pressure recovery from the ideal value. The presence of swirl in the flow from compressor and prediffuser geometry before the dump diffuser influences the flow pattern significantly. In this study, flow structures are numerically predicted with different prediffuser angles and inlet swirl levels for different dump gaps. Streamline distributions and pressure plots on the casing and liner walls are analyzed. Static pressure recovery coefficients are obtained from the pressure distributions across the combustor. The effect of dump gap on the static pressure recovery has also been evaluated. It is observed that the best static pressure recovery can be obtained at optimum values of inlet swirl level and prediffuser angle. Dump gap is found to have significant influence on the static pressure recovery only at small prediffuser angle.

Characterization of Confined Swirl Flows Using Large Eddy Simulations

2001 ◽  
Author(s):  
Jörg Schlüter ◽  
Thilo Schönfeld ◽  
Thierry Poinsot ◽  
Werner Krebs ◽  
Stefan Hoffmann
Keyword(s):  
Large Eddy Simulation ◽  
Gas Turbine ◽  
Vortex Shedding ◽  
Swirling Flow ◽  
Vortical Structure ◽  
Swirl Flow ◽  
Eddy Simulation ◽  
Swirl Flows ◽  
Large Eddy ◽  
Combustion Systems

Since the flame of high intense low NOx gas turbine combustion systems is stabilized by swirl, the analysis of the swirl flow is very crucial to the design and optimization of such combustion systems. Although a huge amount of publications have been provided on this field just a few have used Large Eddy Simulation due to limits in computer resources. Using Large Eddy Simulation the large vortical structure of the flow is resolved leading to a much better insight of the flow features. Hence, in this paper the Large Eddy Simulation has been applied to investigate the non reacting confined swirling flow downstream of a gas turbine burner. A high accuracy of the prediction of the full three dimensional simulation could be pointed out by comparison of the computational results to measurements. Further the large vortical structure and the dynamic behavior of the flow has been analyzed. The formation of a precessing vortex core is visualized. Due to the precessing motion of the central recirculation zone an alternate vortex shedding at the edges of the burner nozzle is induced. From LES Strouhal numbers for the vortex shedding process are calculated which are confirmed by hot wire measurements.

scholarly journals A Numerical Study on the Effect of CO Addition on Flame Temperature and NO Formation in Counterflow CH4/Air Diffusion Flames

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Hongsheng Guo ◽  
W. Stuart Neill
Keyword(s):  
Carbon Monoxide ◽  
Strain Rate ◽  
Diffusion Flames ◽  
Numerical Study ◽  
Formation Rate ◽  
Flame Temperature ◽  
No Emission ◽  
No Formation ◽  
Air Diffusion ◽  
Emission Index

A numerical study was carried out to understand the effect of CO enrichment on flame temperature and NO formation in counterflow CH4/air diffusion flames. The results indicate that when CO is added to the fuel, both flame temperature and NO formation rate are changed due to the variations in adiabatic flame temperature, fuel Lewis number, and chemical reaction. At a low strain rate, the addition of carbon monoxide causes a monotonic decrease in flame temperature and peak NO concentration. However, NO emission index first slightly increases, and then decreases. At a moderate strain rate, the addition of CO has negligible effect on flame temperature and leads to a slight increase in both peak NO concentration and NO emission index, until the fraction of carbon monoxide reaches about 0.7. Then, with a further increase in the fraction of added carbon monoxide, all three quantities quickly decrease. At a high strain rate, the addition of carbon monoxide causes increase in flame temperature and NO formation rate, until a critical carbon monoxide fraction is reached. After the critical fraction, the further addition of carbon monoxide leads to decrease in both flame temperature and NO formation rate.

Numerical Simulation for the Preliminary Design of Fuel Flexible Stationary Gas Turbine Combustors Using Conventional and Alternative Fuels

2012 ◽  
Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
João Roberto Barbosa ◽  
Rob Johan Maria Bastiaans ◽  
Philip de Goey
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
High Efficiency ◽  
Numerical Study ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Gas Turbine Combustor ◽  
Primary Zone

Currently, high efficiency and low emissions are most important requisites for the design of modern gas turbines due to the strong environmental restrictions around the world. In the past years, alternative fuels have been considered for application in industrial gas turbines. Therefore, combustor performance, pollutant emissions and the ability to burn several fuels became of much concern and high priority has been given to the combustor design. This paper describes a methodology focused on the design of stationary gas turbines combustion chambers with the ability to efficiently burn conventional and alternative fuels. A simplified methodology is used for the calculations of the equilibrium temperature and chemical species in the primary zone of a gas turbine combustor. Direct fuel injection and diffusion flames, together with numerical methods like Newton-Raphson, LU Factorization and Lagrange Polynomials, are used for the calculations. Diesel, ethanol and methanol fuels were chosen for the numerical study. A computer code sequentially calculates the main geometry of the combustor. From the numerical simulation it is concluded that the basic gas turbine combustor geometry, for some operating conditions and burning diesel, ethanol or methanol, are of similar sizes, because the development of aerodynamic characteristics predominate over the thermochemical properties. It is worth to note that the type of fuel has a marked effect on the stability and combustion advancement in the combustor. This can be seen when the primary zone is analyzed under a steady-state operating condition. At full power, the pressure is 1.8 MPa and the temperature 1,000 K at the combustor inlet. Then, the equivalence ratios in the primary zone are 1.3933 (diesel), 1.4352 (ethanol) and 1.3977 (methanol) and the equilibrium temperatures for the same operating conditions are 2,809 K (diesel), 2,754 K (ethanol) and 2,702 K (methanol). This means that the combustor can reach similar flame stability conditions, whereas the combustion efficiency will require richer fuel/air mixtures of ethanol or methanol are burnt instead of diesel. Another important result from the numerical study is that the concentration of the main pollutants (CO, CO2, NO, NO2) is reduced when ethanol or methanol are burnt, in place of diesel.

Numerical Study of NOx Emissions in RQL Gas Turbine Combustor

2012 ◽  
Vol 510 ◽  
pp. 545-548
Author(s):  
Liang Yu ◽  
Shu Sheng Yuan ◽  
Zhi Bing Pang ◽  
Yun Liang Wang
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Numerical Study ◽  
Simple Algorithm ◽  
Wall Region ◽  
Gas Turbine Combustor ◽  
Mixing Processes ◽  
Finite Difference Equations ◽  
High Temperature Area ◽  
Exit Temperature

RNG (Renormalization Group) k-ε turbulent model was applied to the numerical simulation of turbulent mixing processes in the RQL gas turbine combustor, and SIMPLE algorithm was used to solve the finite difference equations. The calculated conclusions were used to analyze temperature distribution of the mixed flow field and near-wall region of the flow field, and then discuss the NOx emissions. The results show that the effect of the injector zone geometry and the jet to crossflow momentum flux ratios on the NOx emissions is obvious. The reasonable control of jet is beneficial to reduce the local high temperature area and is able to improve the distribution of the exit temperature. And then achieve the goal of reducing the environmental pollution.

Sign in / Sign up

Export Citation Format

Share Document