Experimental and Numerical Investigation of Fuel-Air Mixing in a Radial Swirler Slot of a Dry Low Emission Gas Turbine Combustor

2014 ◽  
Author(s):  
Festus Eghe Agbonzikilo ◽  
Jill Stewart ◽  
Suresh Kumar Sadasivuni ◽  
Ieuan Owen ◽  
Mike Riley ◽  
...  
Keyword(s):  
Experimental Data ◽  
Large Scale ◽  
Experimental Studies ◽  
Flux Ratio ◽  
Turbulence Models ◽  
Test Facility ◽  
Combustion System ◽  
Fuel Gas ◽  
Low Emission ◽  
Air Mixing

This paper presents the results of an investigation in which the fuel/air mixing process in a single slot within the radial swirler of a dry low emission (DLE) combustion system is explored using air/air mixing. Experimental studies have been carried out on an atmospheric test facility in which the test domain is a large-scale representation of a swirler slot from a Siemens DLE SGT-400 combustion system. Hot air with a temperature of 300°C is supplied to the slot, while the injected fuel gas is represented using air jets with temperatures of about 25°C. Temperature has been used as a scalar to measure the mixing of the jets with the cross-flow. The mixture temperatures were measured using thermocouples while Pitot probes were used to obtain local velocity measurements. The experimental data have been used to validate a computational fluid dynamics (CFD) mixing model. Numerical simulations were carried out using CFD software ANSYS-CFX. Due to the complex three-dimensional flow structure inside the swirler slot, different RANS turbulence models were tested. The shear stress transport (SST) turbulence model was observed to give best agreement with the experimental data. The momentum flux ratio between the main air flow and the injected fuel jet, and the aerodynamics inside the slot, were both identified by this study as major factors in determining the mixing characteristics. It has been shown that mixing in the swirler can be significantly improved by exploiting the aerodynamic characteristics of the flow inside the slot. The validated CFD model provides a tool which will be used in future studies to explore fuel/air mixing at engine conditions.

Experimental and Numerical Investigation of Fuel–Air Mixing in a Radial Swirler Slot of a Dry Low Emission Gas Turbine Combustor

2015 ◽  
Vol 138 (6) ◽  
Author(s):  
Festus Eghe Agbonzikilo ◽  
Ieuan Owen ◽  
Jill Stewart ◽  
Suresh Kumar Sadasivuni ◽  
Mike Riley ◽  
...  
Keyword(s):  
Experimental Data ◽  
Large Scale ◽  
Experimental Studies ◽  
Flux Ratio ◽  
Turbulence Models ◽  
Test Facility ◽  
Combustion System ◽  
Fuel Gas ◽  
Low Emission ◽  
Air Mixing

This paper presents the results of an investigation in which the fuel/air mixing process in a single slot within the radial swirler of a dry low emission (DLE) combustion system is explored using air/air mixing. Experimental studies have been carried out on an atmospheric test facility in which the test domain is a large-scale representation of a swirler slot from a Siemens proprietary DLE combustion system. Hot air with a temperature of 300 °C is supplied to the slot, while the injected fuel gas is simulated using air jets with temperatures of about 25 °C. Temperature has been used as a scalar to measure the mixing of the jets with the cross-flow. The mixture temperatures were measured using thermocouples while Pitot probes were used to obtain local velocity measurements. The experimental data have been used to validate a computational fluid dynamics (CFD) mixing model. Numerical simulations were carried out using CFD software ansys-cfx. Due to the complex three-dimensional flow structure inside the swirler slot, different Reynolds-averaged Navier–Stokes (RANS) turbulence models were tested. The shear stress transport (SST) turbulence model was observed to give best agreement with the experimental data. The momentum flux ratio between the main air flow and the injected fuel jet, and the aerodynamics inside the slot were both identified by this study as major factors in determining the mixing characteristics. It has been shown that mixing in the swirler can be significantly improved by exploiting the aerodynamic characteristics of the flow inside the slot. The validated CFD model provides a tool which will be used in future studies to explore fuel/air mixing at engine conditions.

Investigation of Flow Aerodynamics for Optimal Fuel Placement and Mixing in the Radial Swirler Slot of a Dry Low Emission Gas Turbine Combustion Chamber

2015 ◽  
Vol 138 (5) ◽  
Author(s):  
Festus Eghe Agbonzikilo ◽  
Ieuan Owen ◽  
Suresh Kumar Sadasivuni ◽  
Ronald A. Bickerton
Keyword(s):  
Large Scale ◽  
Fuel Injection ◽  
Orthogonal Design ◽  
Test Facility ◽  
Combustion System ◽  
Mixing Processes ◽  
Baseline Design ◽  
Optimization Study ◽  
Low Emission ◽  
Air Mixing

This paper is concerned with optimizing the fuel–air mixing processes that take place within the radial swirler slot of a dry low emission (DLE) combustion system. The aerodynamics of the flow within the slot is complex and this, together with the placement of the fuel holes with cross injection, controls the mixing of the fuel and air. Computational fluid dynamics (CFD) with the shear stress transport (SST) (k–ω) turbulence model was used for flow and mixing predictions within the radial swirler slot and for conducting a CFD-based design of experiments (DOE) optimization study, in which different parameters related to the fuel injection holes were varied. The optimization study was comprised of 25 orthogonal design configurations in the Taguchi L25 orthogonal array (OA). The test domain for the CFD, and its experimental validation, was a large-scale representation of a swirler slot from the Siemens proprietary DLE combustion system. The DOE study showed that the number of fuel holes, injection hole diameter, and interhole distance are the most influential parameters for determining optimal fuel mixing. Consequently, the optimized mixing configuration obtained from the above study was experimentally tested on an atmospheric test facility. The mixing patterns from experiments at various axial locations across the slot are in good agreement with the mixing predictions from the optimal CFD model. The optimized fuel injection design improved mixing compared with the baseline design by about 60%.

Investigation of Flow Aerodynamics for Optimal Fuel Placement and Mixing in the Radial Swirler Slot of a Dry Low Emission Gas Turbine Combustion Chamber

2015 ◽  
Author(s):  
Festus Eghe Agbonzikilo ◽  
Ieuan Owen ◽  
Suresh Kumar Sadasivuni ◽  
Ronald A. Bickerton
Keyword(s):  
Large Scale ◽  
Fuel Injection ◽  
Orthogonal Design ◽  
Test Facility ◽  
Combustion System ◽  
Original Design ◽  
Mixing Processes ◽  
Low Emission ◽  
Air Mixing ◽  
Computational Fluid Dynamics Cfd

This paper presents the results of a detailed investigation of the fuel-air mixing processes that take place within the radial swirler slot of a dry low emission combustion system. The aerodynamics of the flow within the slot is complex and this, together with the placement of the fuel holes with cross injection, controls the mixing of the fuel and air. Computational fluid dynamics (CFD) with the Shear Stress Transport (k-ω) turbulence model was used for flow and mixing predictions within the radial swirler slot and for conducting a CFD-based Design of Experiments (DOE) optimisation study, in which different parameters related to the fuel injection holes were varied. The optimisation study was comprised of 25 orthogonal design configurations in a Taguchi L25 orthogonal array. The test domain for the CFD, and its experimental validation, was a large-scale representation of a swirler slot from a Siemens proprietary DLE combustion system. The DOE study showed that the number of fuel holes, injection hole diameter and inter-hole distance are the most influential parameters for determining optimal fuel mixing. Consequently, the optimised mixing configuration obtained from the above study was experimentally tested on an atmospheric test facility. The mixing patterns from experiments at various axial locations across the slot are in good agreement with the mixing predictions from the optimal CFD model. The optimised fuel injection design improved mixing compared with the original design by about 60%.

Low-Emission, Liquid Fuel Combustion System for Conventional and Alternative Fuels Developed by the Scaling Analysis

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Yonas Niguse ◽  
Ajay Agrawal
Keyword(s):  
Alternative Fuels ◽  
Large Scale ◽  
Small Scale ◽  
Scaling Analysis ◽  
Combustion System ◽  
Low Emission ◽  
Wide Range ◽  
Air Mixing ◽  
Scaling Parameters ◽  
Fine Spray

The objective of this study is to develop a theoretical basis for scalability considerations and design of a large-scale combustor utilizing flow blurring (FB) atomization. FB atomization is a recently discovered twin-fluid atomization concept, reported to produce fine spray of liquids with wide range of viscosities. Previously, we have developed and investigated a small-scale swirl-stabilized combustor of 7-kWth capacity. Spray measurements have shown that the FB injector's atomization capability is superior when compared to other techniques, such as air blast atomization. However, despite these favorable results, scalability of the FB injector and associated combustor design has never been explored for large capacity; for example, for gas turbine applications. In this study, a number of dimensionless scaling parameters that affect the processes of atomization, fuel–air mixing, and combustion are analyzed, and scaling criteria for the different components of the combustion system are selected. Constant velocity criterion is used to scale key geometric components of the system. Scaling of the nonlinear dimensions and complex geometries, such as swirler vanes and internal parts of the injector is undertaken through phenomenological analysis of the flow processes associated with the scaled component. A scaled-up 60-kWth capacity combustor with FB injector is developed and investigated for combustion performance using diesel and vegetable oil (VO) (soybean oil) as fuels. Results show that the scaled-up injector's performance is comparable to the smaller scale system in terms of flame quality, emission levels, and static flame stability. Visual flame images at different atomizing air-to-liquid ratio by mass (ALR) show mainly blue flames, especially for ALR > 2.8. Emission measurements show a general trend of lower CO and NOx levels at higher ALRs, replicating the performance of the small-scale combustion system. Flame liftoff height at different ALRs is similar for both scales. The scaled-up combustor with FB injector preformed robustly with uncompromised stability for the range of firing rates (FRs) above 50% of the design capacity. Experimental results corroborate with the scaling methodology developed in this research.

Low Emission, Liquid Fuel Combustion System for Conventional and Alternative Fuels Developed by the Scaling Analysis

2015 ◽  
Author(s):  
Yonas G. Niguse ◽  
Ajay K. Agrawal
Keyword(s):  
Alternative Fuels ◽  
Large Scale ◽  
Small Scale ◽  
Scaling Analysis ◽  
Combustion System ◽  
Low Emission ◽  
Wide Range ◽  
Air Mixing ◽  
Scaling Parameters ◽  
Fine Spray

The objective of this study is to develop a theoretical basis for scalability considerations and design of a large scale combustor utilizing flow blurring (FB) atomization. FB atomization is a recently discovered twin-fluid atomization concept, reported to produce fine spray of liquids with wide range of viscosities. Previously, we have developed and investigated a small scale swirl-stabilized combustor of 7-kWth capacity. Spray measurements have shown that the FB injector’s atomization capability is superior when compared to other techniques, such as air blast atomization. However, despite these favorable results, scalability of the FB injector and associated combustor design has never been explored for large capacity, for example, for gas turbine applications. In this study, a number of dimensionless scaling parameters that affect the processes of atomization, fuel-air mixing, and combustion are analyzed, and scaling criteria for the different components of the combustion system are selected. Constant velocity criterion is used to scale key geometric components of the system. Scaling of the nonlinear dimensions and complex geometries, such as swirler vanes and internal parts of the injector is undertaken through phenomenological analysis of the flow processes associated with the scaled component. A scaled up 60-kWth capacity combustor with FB injector is developed and investigated for combustion performance using diesel and vegetable oil (soybean oil) as fuels. Results show that the scaled-up injector’s performance is comparable to the smaller scale system in terms of flame quality, emission levels, and static flame stability. Visual flame images at different air to liquid ratio by mass (ALR) show mainly blue flames, especially for ALR > 2.8. Emission measurements show a general trend of lower CO and NOx levels at higher ALRs, replicating the performance of the small scale combustion system. Flame liftoff height at different ALRs is similar for both scales. The scaled-up combustor with FB injector preformed robustly with uncompromised stability for the range of firing rates above 50% of the design capacity. Experimental results corroborate with the scaling methodology developed in this research.

Combustion System Development and Testing for MAN’s New Industrial Gas Turbines MGT 6100 and MGT 6200

2014 ◽  
Author(s):  
Frank Reiss ◽  
Sven-Hendrik Wiers ◽  
Ulrich Orth ◽  
Emil Aschenbruck ◽  
Martin Lauer ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Test Facility ◽  
Combustion System ◽  
Test Rig ◽  
Low Emission ◽  
Pressure Test ◽  
Industrial Gas Turbines ◽  
And Performance

This paper describes the development and test results of the low emission combustion system for the new industrial gas turbines in the 6–7 MW class from MAN Diesel & Turbo. The design of a robust combustion system and the achievement of very low emission targets were the most important design goals of the combustor development. During the design phase, the analysis of the combustor (i.e. burner design, air distribution, liner cooling design) was supported with different CFD tools. This advanced Dry Low Emission can combustion system (ACC) consists of 6 cans mounted externally on the gas turbine. The behavior and performance of a single can sector was tested over a wide load range and with different boundary conditions; first on an atmospheric test rig and later on a high pressure test rig with extensive instrumentation to ensure an efficient test campaign and accurate data. The atmospheric tests showed a very good performance for all combustor parts and promising results. The high pressure tests demonstrated very stable behavior at all operation modes and very low emissions to satisfy stringent environmental requirements. The whole operation concept of the combustion system was tested first on the single-can high pressure test bed and later on twin and single shaft gas turbines at MAN’s gas turbine test facility. During the engine tests, the can combustors demonstrated the expected combustion performance under real operation conditions. All emissions and performance targets were fully achieved. On the single shaft engine, the combustors were running with single digit ppm NOx levels between 50% and 100% load. The validation phase and further optimization of the gas turbines and the engine components are ongoing. The highlights of the development process and results of the combustor and engine tests will be presented and discussed within this paper.

Combustion System Update SGT5-4000F: Design, Testing and Validation

2013 ◽  
Author(s):  
Boris F. Kock ◽  
Bernd Prade ◽  
Benjamin Witzel ◽  
Holger Streb ◽  
Mike H. Koenig
Keyword(s):  
Gas Turbines ◽  
High Reliability ◽  
Product Development Process ◽  
Test Facility ◽  
Combustion System ◽  
Lean Premixed Combustion ◽  
Air Mixing ◽  
Acoustic Stability ◽  
Combustion Tests ◽  
Cooling Air

The first Siemens AG SGT5-4000F engine with hybrid burner ring combustor (HBR) was introduced in 1996. Since then, frequent evolutionary design improvements of the combustion system were introduced to fulfill the continuously changing market requirements. The improvements particularly focused on increased thermodynamic performance, reduced emissions, and increasing operational flexibility in terms of load gradients, fuel flexibility, and turndown capability. According to the Siemens product development process, every design evolution had to pass several validation steps to ensure high reliability and best performance. The single steps included cold flow and mixing tests at atmospheric pressure, high-pressure combustion tests in full-scale sector combustion test rigs, and full engine tests at the Berlin test facility (BTF). After successful validation, the design improvements were gradually released for commercial operation. In a first step, cooling air reduction features have been implemented in 2005, followed by the introduction of a premixed pilot as second step in 2006. Both together resulted in a significant reduction of the NOx emissions of the system. In a third step, an aerodynamic burner modification was introduced in 2007, which improved the thermo-acoustic stability of the system towards higher turbine inlet temperatures and adapted to fuel preheating to allow for increased cycle efficiency. All three features together have been released as package in 2010 and to date accumulated more than 50,000 operating hours (fleet leader 24,000). This paper reports upon the steps towards this latest design status of the SGT5-4000F and presents results from typical focus areas of lean premixed combustion systems in gas turbines including aero-dynamical optimization, fuel/air mixing improvements and cooling air management in the combustor.

Integrated Experimental and Numerical Approach for Fuel-Air Mixing Prediction in a Heavy-Duty Gas Turbine LP Burner

2000 ◽  
Vol 123 (4) ◽  
pp. 803-809 ◽  
Author(s):  
G. Mori ◽  
S. Razore ◽  
M. Ubaldi ◽  
P. Zunino
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Numerical Procedure ◽  
Turbulence Models ◽  
Mie Scattering ◽  
Optical Measurements ◽  
Heavy Duty ◽  
Experimental Apparatus ◽  
Air Mixing ◽  
Heavy Duty Gas Turbine

An integrated experimental-numerical procedure has been developed for fuel-air mixing prediction in a heavy-duty gas turbine burner. Optical measurements of the degree of mixing have been performed in a full-scale test rig operating with cold flow. Experimental data have been utilized to validate a CFD RANS numerical model. In fact, it is recognized that the turbulence behavior of jets in swirling air-flow stream is not accurately described by standard k-ε turbulence models; therefore advanced turbulence models have been assessed by means of experimental data. The degree of mixing between simulated fuel and air streams has been evaluated at the burner exit section by means of a planar Mie scattering technique. The experimental apparatus consists of a pulsed Nd:YAG laser and a high resolution CCD video camera connected to a frame grabber. The acquired instantaneous images have been processed through specific procedures that also take into account the laser beam spatial nonuniformity. A second-order discretization scheme with a RSM turbulence model gives the best accordance with the experimental data. Such CFD model will be part of a more general method addressed to numerical prediction of turbulent combustion flames in LP technology.

Experimental Measurements of an Air Conditioner Performance

2002 ◽  
Author(s):  
Luis Rosario ◽  
Muhammad M. Rahman ◽  
Jose L. F. Porteiro
Keyword(s):  
Experimental Data ◽  
Air Conditioning ◽  
Experimental Studies ◽  
Operating Conditions ◽  
System Capacity ◽  
Coefficient Of Performance ◽  
Test Facility ◽  
Experimental Program ◽  
Air Conditioner ◽  
Test Unit

The performance of the air conditioner was tested in an extensive experimental program using the environmentally controlled chambers in a test facility. Two psychometric rooms provided constant ambient temperature and humidity conditions for a test unit using ASHRAE standard procedures [1]. The indoor and outdoor units were placed into separate environmental chambers, which provided precise temperature, humidity, and airflow conditions for simulation of various operating conditions. The first goal of the experimental program was to define the range of conditions over which the test unit should be tested. The second goal of the experimental studies was to determine the performance of the test unit under the defined conditions. All air conditioner performance data has been collected with air side instrumentation only. Experimental tests were performed using the test unit over a range of outdoor temperatures between 22.4°C (80°F) and 40.6°C (105°F) and indoor temperatures between 18.3°C (65°F) and 35°C (95°F). Analysis of the experimental data was performed by studying air conditioning parameters such as heat rejection rate qc, compressor power W, system capacity qe, and coefficient of performance COP. The analysis was accomplished with the variation of a boundary condition. The sensitivity analysis of experimental data gave expected results when compared to those shown by air conditioning units similar to our test unit.

Development Approach to the Dry Low Emission Combustion System of MAN Diesel and Turbo Gas Turbines

2014 ◽  
Author(s):  
Holger Huitenga ◽  
Eric R. Norster
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Field Tests ◽  
Test Facility ◽  
Design Parameters ◽  
Combustion System ◽  
Low Emission ◽  
Lean Premixed ◽  
Industrial Gas Turbines ◽  
Gas Pumping

The THM series of industrial gas turbines covers a power range of 6 to 12.5 MW and has been improved and uprated over many years. The majority of turbines installed are still in commercial operation and they are mainly used for compressor drives but also find generator applications. In recent years the constraints of emission legislations for new and existing gas turbines has made a development programme for a dry low emission (DLE) combustion system essential. The combustion system apart from meeting latest emission targets of 75 mg/mN3 NOx and 100 mg/mN3 CO must be suitable for both, new and retrofit engine options and therefore compact for standard enclosure installation. In addition the design should be simple and robust with the same accessibility as the existing standard combustion system. The paper describes the design and development steps to provide a prototype lean premixed DLE combustion system. The basic approach for a simple lean premixed design together with aero-thermodynamic sizing for pressure loss, flow proportions, stability and cooling is described. The initial efforts were directed to a system for the 11 MW THM 1304-11AP machine, with combustor atmospheric testing to verify design parameters and operating limits. The development was continued by subsequent high pressure testing of the prototype, starting with suitable units in the MAN engine test facility, omitting any high pressure rig tests. Field tests were carried out on a compressor drive application on a gas pumping station to prove long term durability. Adaptations of the design are now engine-tested for other THM models, even recuperated ones. Also, the combustor technology and methods developed here provide the basis for the combustors on the new MAN MGT 6100 and 6200 engines [1].

Sign in / Sign up

Export Citation Format

Share Document