The Influence of Film Cooling on Emissions for a Low NOx Radial Swirler Gas Turbine Combustor

2001 ◽  
Author(s):  
G. E. Andrews ◽  
M. N. Kim
Keyword(s):  
Mach Number ◽  
Gas Turbine ◽  
Flow Rate ◽  
Film Cooling ◽  
Equivalence Ratio ◽  
Air Flow ◽  
Gas Turbine Combustor ◽  
Cooling Flow ◽  
Full Coverage ◽  
Primary Zone

An experimental investigation was undertaken of the influence on emissions of full coverage discrete hole film cooling of a lean low NOx radial swirler natural gas combustor. The combustor used radial swirler vane passage fuel injection on the centre of the vane passage inlet. The test configuration was similar to that used in the Alstom Power Tornado and related family of low NOx gas turbines. The test conditions were simulated at atmospheric pressure at the flow condition of lean low NOx gas turbine primary zones. The tests were carried out at an isothermal flow Mach number of 0.03, which represents 60% of industrial gas turbine combustor airflow through the swirl primary zone. The effusion film cooling used was Rolls-Royce Transply, which has efficient internal cooling of the wall as well as full coverage discrete hole film cooling. Film cooling levels of 0, 16 and 40% of the primary zone airflow were investigated for a fixed total primary zone air flow and reference Mach number of 0.03. The results showed that there was a major increase in the NOx emissions for 740K inlet temperature and 0.45 overall equivalence ratio from 6ppm at zero film cooling air flow to 32ppm at 40% coolant flow rate. CO emissions increased from 25ppm to 75ppm for the same increase in film cooling flow rate. It was shown that the main effect was the creation of a richer inner swirler combustion with a surrounding film cooling flow that did not mix well with the central swirling combustion. The increase in NOx and CO could be predicted on the basis of the central swirl flow equivalence ratio.

Experimental Analysis of Combustion in Gas Turbine

2019 ◽  
Author(s):  
M. S. N. Murthy ◽  
Subhash Kumar ◽  
Sheshadri Sreedhara
Keyword(s):  
Gas Turbine ◽  
Flow Rate ◽  
Experimental Analysis ◽  
Air Flow ◽  
Measuring System ◽  
Maximum Pressure ◽  
Gear Pump ◽  
Air Flow Rate ◽  
Gas Turbine Combustor ◽  
Turbine Engine

Abstract This paper presents the methodology and results of an experimental analysis of combustion in a gas turbine combustor. The experimental setup is designed to imitate the conditions of a working gas turbine engine (GT), using an actual gas turbine combustor. Air is supplied by a heavy-duty air compressor at a maximum pressure of 7 bar to the combustor through an air pipe catering to the developing length. The air flow rate is measured using an ASME standard Venturimeter along with a manometer. The air flow rate and pressure are controlled by a combination of air outlet valve placed before developing length and by a throttle orifice in the exhaust duct at combustor outlet. Diesel fuel used in the experiments is provided at required atomizing pressure by a gear pump. Mass flow rate and pressure of fuel is controlled by combination of valves and varying the speed of gear pump using a variable speed electric motor. Combustion is initiated in a conventional pilot ignition unit using a spark plug and fuel burner. Fuel flow rate is measured accurately using a unique catch and time measuring system at the inlet of the gear pump.

Numerical Simulation to Characterize Homogeneity of Air-Fuel Mixture for Premixed Combustion in Gas Turbine Combustor

2012 ◽  
Author(s):  
Kamalika Chatterjee ◽  
Arkadeep Kumar ◽  
Souvick Chatterjee ◽  
Achintya Mukhopadhyay ◽  
Swarnendu Sen
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Flow Rate ◽  
Combustion Zone ◽  
Equivalence Ratio ◽  
Fuel Mixture ◽  
Premixed Combustion ◽  
Internal Diameter ◽  
Gas Turbine Combustor ◽  
Ansys Fluent

Homogeneity in mixing of air and fuel in premixed combustion for a gas turbine combustor is a critical criterion to ensure efficient combustion and less environmental hazards. The current work deals with determining this homogenous characteristic of air-fuel mixture through computational simulation to specify homogeneity for a particular premixing length and equivalence ratio required for gas turbine combustion. A 3-D geometry of combustion chamber with combustion zone of internal diameter 6 cm is constructed. A premixing tube is augmented with the combustion chamber which has one air inlet port at the bottom and 3 fuel inlet ports. Air-fuel mixture is considered to enter the combustion zone with inlet swirl. The homogeneity of the mixture is found out at the dump plane and other important planes from simulation done with ANSYS FLUENT® for the meshed geometry. The results show whether mixing of air and fuel is full or partial and the extent of partial premixing. The parameters varied in the ANSYS FLUENT®. based simulation are the premixing length i.e. port of entry of fuel, the fuel flow rate i.e. the equivalence ratio and the air flow rate.

Prediction of lean blowout performance on variation of combustor inlet area ratio for micro gas turbine combustor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kirubakaran V. ◽  
Naren Shankar R.
Keyword(s):  
Gas Turbine ◽  
Mass Flow ◽  
Equivalence Ratio ◽  
Area Ratio ◽  
Gas Temperature ◽  
Gas Turbine Combustor ◽  
Content Type ◽  
Lean Blowout ◽  
Micro Gas Turbine ◽  
Primary Zone

Purpose This paper aims to predict the effect of combustor inlet area ratio (CIAR) on the lean blowout limit (LBO) of a swirl stabilized can-type micro gas turbine combustor having a thermal capacity of 3 kW. Design/methodology/approach The blowout limits of the combustor were predicted predominantly from numerical simulations by using the average exit gas temperature (AEGT) method. In this method, the blowout limit is determined from characteristics of the average exit gas temperature of the combustion products for varying equivalence. The CIAR value considered in this study ranges from 0.2 to 0.4 and combustor inlet velocities range from 1.70 to 6.80 m/s. Findings The LBO equivalence ratio decreases gradually with an increase in inlet velocity. On the other hand, the LBO equivalence ratio decreases significantly especially at low inlet velocities with a decrease in CIAR. These results were backed by experimental results for a case of CIAR equal to 0.2. Practical implications Gas turbine combustors are vulnerable to operate on lean equivalence ratios at cruise flight to avoid high thermal stresses. A flame blowout is the main issue faced in lean operations. Based on literature and studies, the combustor lean blowout performance significantly depends on the primary zone mass flow rate. By incorporating variable area snout in the combustor will alter the primary zone mass flow rates by which the combustor will experience extended lean blowout limit characteristics. Originality/value This is a first effort to predict the lean blowout performance on the variation of combustor inlet area ratio on gas turbine combustor. This would help to extend the flame stability region for the gas turbine combustor.

Experimental Characterization of Premixed Flame in Gas Turbine Combustor With Spectroscopy and RGB Analysis

2012 ◽  
Author(s):  
Arkadeep Kumar ◽  
Kamalika Chatterjee ◽  
Achintya Mukhopadhyay ◽  
Swarnendu Sen
Keyword(s):  
Gas Turbine ◽  
Flow Rate ◽  
Equivalence Ratio ◽  
Graphical Representation ◽  
Chemical Species ◽  
Fuel Mixture ◽  
Electromagnetic Spectrum ◽  
Gas Turbine Combustor ◽  
Flame Monitoring

Gas turbine combustion has been one of the principal sources for power generation and propulsion systems. Recent research thrust on flame monitoring for characterization of flame behavior has gained prominence for several reasons — notably for performance of combustor in aerospace propulsion and power plant applications, reduction in pollutant levels like NOx, and fire safety engineering, Lean air-fuel mixture leads to efficient combustion with lesser emissions, albeit with risk of Lean blow out (LBO). Flame monitoring is done to find out LBO point-which occurs by progressively varying the Air-fuel ratio or equivalence ratio. The current paper monitors the characteristics of lean premixed, swirl-stabilized, LPG fueled, dump combustor with the help of spectroscopy and high resolution camera images. Chemiluminescence is being used for determination of combustion characteristics. The spectroscopic peaks for chemical species like - OH* and CH* radicals and water vapor are found at varying parameters like air-fuel premixing and equivalence ratio. Blow off characteristics which occur in gas turbine combustor when going from rich to lean mixture are investigated. The comparison of the averaged red, green and blue (R, G, B) values has been done by graphical representation. The spectroscopic data are co-related with the RGB analysis results- and the location of spectroscopic peaks of intensities and their correspondence with electromagnetic spectrum in investigated. The behavior of peak intensities of Red, Green, Blue alongwith irradiation by chemical species – with the change in parameters like air flow rate, fuel flow rate or equivalence ratio and the extent of air-fuel premixing are investigated. Metrics for detecting the approach of impending LBO are proposed from the spectroscopic results.

Soot Formation and Its Effect in an Aero Gas Turbine Combustor

2019 ◽  
Vol 36 (1) ◽  
pp. 61-73 ◽  
Author(s):  
R. K. Mishra ◽  
Sunil Chandel
Keyword(s):  
Gas Turbine ◽  
Equivalence Ratio ◽  
Soot Formation ◽  
Cone Angle ◽  
Peak Temperature ◽  
Soot Concentration ◽  
Gas Turbine Combustor ◽  
Spray Cone ◽  
Primary Zone ◽  
Soot Deposit

Abstract Soot formation and the effect of soot deposit on the performance and integrity on an aero gas turbine combustor has been studied. Defective atomizer or blockage of air passages creates a fuel rich mixture which promotes soot formation in combustor primary zone. The temperature field and soot concentration inside the liner has been analyzed at high equivalence ratio using computational model in CFX. The peak temperature in primary zone increases till equivalence ratio reaches ϕ=1.1. But at high equivalence ratio, i. e., ϕ≥1.2, the peak temperature in primary zone decreases and that in dilution zone increases. Soot concentration increases at liner front end as well as in dilution zone when equivalence ratio increases from 1.25 to 3.0. Erosion and distortion of atomizer flow passages cause higher spray cone angle which again increases the soot concentration. Soot deposit inside liner has detrimental effect on the life and performance of the combustor as well as of the aero engine.

Effects of Oscillations in the Main Flow due to Thermo Acoustic Fields in a Gas Turbine Combustor on Film Cooling

2016 ◽  
Author(s):  
Seung Il Baek ◽  
Savas Yavuzkurt
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Gas Turbine ◽  
Flow Rate ◽  
Film Cooling ◽  
Jet Flow ◽  
Main Flow ◽  
Wave Form ◽  
Gas Turbine Combustor ◽  
Wave Forms

The objective of this study is to understand the effects of oscillations in the main flow and the film cooling jets caused by the thermoacoustic fields formed in a gas turbine combustor on film cooling. As a first step, CFD simulations are performed for the case of steady mainstream and steady film cooling jets for validation of models and simulations and compared with other studies trying to predict adiabatic effectiveness under similar operating conditions. Based on the knowledge gained on the capability and limitations of different turbulence models for the steady simulations, simulations were extended to unsteady main flow and unsteady cooling jets. The unsteady simulations are performed using URANS-realizable k-ε turbulence model and LES-Smagorinsky-Lilly model. Initially, oscillations due to the combustion instabilities are approximated to be in sinusoidal form. For unsteady main flow and cooling jet simulations, results from the Seo et al. [3] experimental study were selected for comparison with CFD results. The effects of different frequencies (2, 16, 32 Hz) on film cooling are investigated. In each case, average blowing ratio was M=0.5. The results show that if the frequencies of the main flow and the cooling jet flow are increased, the adiabatic centerline effectiveness is decreased and the heat transfer coefficient is increased. Some representative results are: if the frequency of the main flow is increased from 0 Hz to 2 Hz, 16 Hz, or 32 Hz for L/D=1.6, the centerline effectiveness is decreased about 10%, 12%, or 47% and the spanwise-averaged heat transfer coefficient is increased around 1%, 2%, or 4% respectively. If the frequency of the mainstream and the jet flow is increased, the amplitude of the pressure difference between the mainstream and the plenum is increased and the amplitude of coolant flow rate oscillation is increased. Additionally, rectangular or triangular wave forms are used for mainstream and coolant jet flow in order to see the effect on the results and total 36 cases are simulated and effects of changing wave form are investigated. In each case, coolant flow rate was the same as sinusoidal wave forms. It seems like rectangular wave form for main flow at 2 Hz has a negative effect on film cooling performance whereas the same wave form for coolant jet at 32 Hz has a positive effect.

Characteristics of Volcanic Ash in a Gas Turbine Combustor and Nozzle Guide Vanes

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Lei-Yong Jiang ◽  
Yinghua Han ◽  
Prakash Patnaik
Keyword(s):  
Gas Turbine ◽  
Volcanic Ash ◽  
Inlet Temperature ◽  
Gas Turbine Combustor ◽  
Flow Passage ◽  
Guide Vanes ◽  
Cooling Flow ◽  
Cooling Passage ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

To understand the physics of volcanic ash impact on gas turbine hot-components and develop much-needed tools for engine design and fleet management, the behaviors of volcanic ash in a gas turbine combustor and nozzle guide vanes (NGV) have been numerically investigated. High-fidelity numerical models are generated, and volcanic ash sample, physical, and thermal properties are identified. A simple critical particle viscosity—critical wall temperature model is proposed and implemented in all simulations to account for ash particles bouncing off or sticking on metal walls. The results indicate that due to the particle inertia and combustor geometry, the volcanic ash concentration in the NGV cooling passage generally increases with ash size and density, and is less sensitive to inlet velocity. It can reach three times as high as that at the air inlet for the engine conditions and ash properties investigated. More importantly, a large number of the ash particles entering the NGV cooling chamber are trapped in the cooling flow passage for all four turbine inlet temperature conditions. This may reveal another volcanic ash damage mechanism originated from engine cooling flow passage. Finally, some suggestions are recommended for further research and development in this challenging field. To the best of our knowledge, it is the first study on detailed ash behaviors inside practical gas turbine hot-components in the open literature.

scholarly journals The Development of a Diesel Burning Combustion Chamber With a Multiple Jet Primary Zone

1987 ◽  
Author(s):  
R. V. Cottington ◽  
J. P. D. Hakluytt ◽  
J. R. Tilston
Keyword(s):  
Gas Turbine ◽  
Shear Layers ◽  
Fuel Quality ◽  
Carbon Formation ◽  
Gas Turbine Combustor ◽  
Smoke Emission ◽  
Primary Zone ◽  
Efficient Combustion ◽  
Operational Range ◽  
Lean Conditions

A new primary zone for a gas turbine combustor has been developed which achieves efficient combustion in fuel lean conditions for minimizing carbon formation. This uses a large number of jets in the head of the chamber to generate independent shear layers in a co-operative array. Good combustion performance, wide fuel/air ratio operational range and tolerance to fuel quality have been demonstrated on research rigs. The combustor itself has been developed to an engine standard for a naval gas turbine required to operate with low smoke emission on distillate diesel fuel. The rig programme used to optimise the design is described together with results from engine evaluation. Practical advantages of this type of chamber apply equally to aero applications on kerosene.

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