CFD Based Analysis of Burner Fuel Air Mixing Over a Range of Air Inlet and Fuel Pre-Heat Temperatures for a Siemens V94.3A Gas Turbine Burner

2006 ◽  
Author(s):  
O. R. Darbyshire ◽  
C. W. Wilson ◽  
A. Evans ◽  
S. B. M. Beck
Keyword(s):  
Gas Turbine ◽  
Computational Effort ◽  
Ambient Conditions ◽  
Fuel Gas ◽  
3 Dimensional ◽  
Continuity Equations ◽  
Air Inlet ◽  
Air Mixing ◽  
Inlet Conditions ◽  
Thermal Nox

The homogeneity of the fuel/air mix entering the combustion chamber of a gas turbine is known to be a factor in both the emissions performance (with poor mixing resulting in local hotspots and the formation of thermal NOx) and the generation of acoustic vibrations (humming). Obviously it is desirable to reduce both pollutants and unwanted acoustics as far as possible. The aim of this paper is to study the relationship between the local inlet conditions and the mixing of the fuel and air, specifically looking at the effects of fuel gas preheating and inlet air temperature on mixedness at the combustor inlet. A CFD model of the lean pre-mixed combustor for a Siemens v94.3A gas turbine was used to analyse the problem. The 3-dimensional model employs a structured mesh scheme and uses the symmetry of the burner to reduce computational effort. The model was solved using a 2nd order discretisation of the momentum and continuity equations along with the RNG k-ε turbulence model to provide closure. The boundary conditions for the model were taken from data obtained from in service measurements. Several runs were made using air inlet temperatures varying from −10°C to 30°C and gas inlet temperatures from 10°C to 450°C. The data obtained from the CFD simulations was processed to give an indication of the quality of the fuel/air mixing for each set of inlet conditions. This was then used to create a tool which can be used to determine the amount of gas pre-heat required to achieve the best possible mixing for a given set of ambient conditions. An estimation of the NOx produced at different conditions was derived from the mixing data. Analysis of the results showed that increasing the gas preheat produces an improvement in the mixing of the fuel and air in the burner. This improvement in mixing also resulted in a reduction in the estimated amount of NOx produced.

The Impact of Model Assumptions on the CFD Assisted Design of Gas Turbine Packages

2019 ◽  
Author(s):  
Gabriele Lucherini ◽  
Vittorio Michelassi ◽  
Stefano Minotti
Keyword(s):  
Gas Turbine ◽  
Large Scale ◽  
Structural Integrity ◽  
Ventilation System ◽  
Gas Diffusion ◽  
Computational Effort ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Fuel Gas ◽  
The Impact

Abstract A gas turbine is usually installed inside a package to reduce the acoustics emissions and protect against adverse environmental conditions. An enclosure ventilation system is keeps temperatures under acceptable limits and dilutes any potentially explosive accumulation of gas due to unexpected leakages. The functional and structural integrity as well as certification needs of the instrumentation and auxiliary systems in the package require that temperatures do not exceed a given threshold. Moreover, accidental fuel gas leakages inside the package must be studied in detail for safety purposes as required by ISO21789. CFD is routinely used in BHGE (Baker Hughes, a GE Company) to assist in the design and verification of the complete enclosure and ventilation system. This may require multiple CFD runs of very complex domains and flow fields in several operating conditions, with a large computational effort. Modeling assumptions and simulation set-up in terms of turbulence and thermal models, and the steady or unsteady nature of the simulations must be carefully assessed. In order to find a good compromise between accuracy and computational effort the present work focuses on the analysis of three different approaches, RANS, URANS and Hybrid-LES. The different computational approaches are first applied to an isothermal scaled-down model for validation purposes where it was possible to determine the impact of the large-scale flow unsteadiness and compare with measurements. Then, the analysis proceeds to a full-scale real aero-derivative gas turbine package. in which the aero and thermal field were investigated by a set of URANS and Hybrid-LES that includes the heat released by the engine. The different approaches are compared by analyzing flow and temperature fields. Finally, an accidental gas leak and the subsequent gas diffusion and/or accumulation inside the package are studied and compared. The outcome of this work highlights how the most suitable approach to be followed for industrial purposes depends on the goal of the CFD study and on the specific scenario, such as NPI Program or RQS Project.

Development of a Liquid Fuel System for GE MS5002E Gas Turbine: Rig Test Validation of the Combustor Performance

2014 ◽  
Author(s):  
Alessandro Zucca ◽  
Sergey Khayrulin ◽  
Natalya Vyazemskaya ◽  
Borys Shershnyov ◽  
Geoff Myers
Keyword(s):  
Gas Turbine ◽  
Liquid Fuel ◽  
Water Injection ◽  
Dual Fuel ◽  
Market Segment ◽  
Fuel System ◽  
Ambient Conditions ◽  
Fuel Gas ◽  
Gas Market ◽  
Commercial Opportunity

Analysis of the Oil & Gas market segment showed that potential MS5002E customers could benefit from firing the gas turbine with distillate oil as a back-up fuel, mainly to provide power when the fuel gas is not available (e.g. when the plant itself is being commissioned). To address this customer need, the design of a dual fuel system for such mission should target simplicity, reliability and minimize the additional cost with respect to the single gas version. To achieve these targets, the development of the dual fuel system for the MS5002E leveraged the efforts made by GE for the design of a liquid fuel system for Frame 9F-1 series with no need of atomization air. Moreover, the emission capability during liquid fuel operation was enhanced allowing the mixing of water and fuel before injection in the combustion chamber and using of improved injection technology, thus improving the efficiency of water injection with a significant reduction in the required water flow rates; the importance of this achievement is related to both the increasingly stringent regulation on this subject and the often poor availability of water in the Oil & Gas market segment. The system is capable of continuous operation without water injection for applications where emissions are not critical; in these cases a small amount of demineralized water is employed occasionally for fuel line cooling and flushing, thus helping to guarantee constant performances of the injectors, and to maintain liquid fuel start-up capability over time. This paper presents the expected performance, in terms of ignition capability, emissions, operability and expected hardware durability on LF/water-fuel emulsion operation, based on a single can rig test campaign. The new liquid fuel cartridges were tested from ignition to base load at ISO and extreme simulated ambient conditions, both with and without water injection, showing promising performance in terms of combustor operability and emissions. All the combustor components were instrumented with thermocouples to assess variations in the hardware thermal levels with respect to the single gas conditions, and identify possible issues related to the transient and steady-state liquid fuel operation. Further development and testing will be carried out in the next phases of the development, and the performance will be confirmed by a dedicated engine test at the first commercial opportunity.

Numerical Simulation of the Unsteady Flow Field in an Axial Gas Turbine Rim Seal Configuration

2004 ◽  
Author(s):  
Ralf Jakoby ◽  
Thomas Zierer ◽  
Klas Lindblad ◽  
Jonas Larsson ◽  
Laurent deVito ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Gas Turbine ◽  
Large Scale ◽  
Computational Effort ◽  
Special Focus ◽  
Computational Domain ◽  
3 Dimensional ◽  
Numerical Resolution ◽  
Cooling Air

The fluid flow in gas turbine rim seals and the sealing effectiveness are influenced by the interaction of the rotor and the stator disk and by the external flow in the hot gas annulus. The resulting flow structure is fully 3-dimensional and time-dependant. The requirements to a sufficiently accurate numerical prediction for front and back cavity flows are discussed in this paper. The results of different numerical approaches are presented for an axial seal configuration. This covers a full simulation of the time-dependant flow field in a 1.5 stage experimental turbine including the main annulus and both rim cavities. This configuration is simplified in subsequent steps in order to identify a method providing the best compromise between a sufficient level of accuracy and the least computational effort. A comparison of the computed cavity pressures and the sealing effectiveness with rig test data shows the suitability of each numerical method. The numerical resolution of a large scale rotating structure that is found in the front cavity is a special focus of this study. The existence of this flow pattern was detected first by unsteady pressure measurements in test rig. It persists within a certain range of cooling air massflows and significantly affects the sealing behaviour and the cavity pressure distribution. This phenomenon is captured with an unsteady calculation using a 360 deg. computational domain. The description of the flow pattern is given together with a comparison to the measurements.

Gas Turbine Compartment Ventilation System

2014 ◽  
Author(s):  
Divya Kothakapu ◽  
Srinivas Avishetti
Keyword(s):  
Gas Turbine ◽  
Static Pressure ◽  
Geometric Model ◽  
Ventilation System ◽  
Pressure Head ◽  
Ambient Conditions ◽  
Fixed Temperature ◽  
3 Dimensional ◽  
Personnel Safety ◽  
American Society

The configuration of the compartment ventilation system is an important requirement in the gas turbine industry. The purpose of heating and ventilation system is to keep the turbine compartment within a fixed temperature envelope for at least personnel safety, equipment protection and reduction of turbine distortion by maintaining circumferentially uniform temperature distribution. The ventilation system also provides capability to detect and dilute the leaks by continually purging potential gas build up areas. Displacement ventilation is commonly used for the above considerations. The current GE approach is to perform CFD analysis to quantify the ventilation fan flow rate and arrive at fan static pressure head through simplified 1-D calculations. A detailed CFD geometric model is developed by including the entire turbine, piping, major support structure, all components with stringent temperature limits, ventilation inlets and outlets, enclosure roof and walls to verify the flow field. The fan static pressure head for various ambient conditions is obtained through 1-D calculations using the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) duct-fitting database. The goal of this work is: (1) accurate modeling of the components within the enclosure for better prediction of component temperatures; (2) consideration of solar radiation; and (3) integration of the 1-Dimensional Flowmaster models and 3-Dimensional CFD results to improve the predictions from One-Dimensional model.

scholarly journals Thermal Energy Storage For Gas Turbine Power Augmentation

2019 ◽  
Vol 3 ◽  
pp. 592-608
Author(s):  
Vasilis Gkoutzamanis ◽  
Anastasia Chatziangelidou ◽  
Theofilos Efstathiadis ◽  
Anestis Kalfas ◽  
Alberto Traverso ◽  
...  
Keyword(s):  
Energy Storage ◽  
Gas Turbine ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Air Inlet ◽  
Conventional Cooling

This work is concerned with the investigation of thermal energy storage (TES) in relation to gas turbine inlet air cooling. The utilization of such techniques in simple gas turbine or combined cycle plants leads to improvement of flexibility and overall performance. Its scope is to review the various methods used to provide gas turbine power augmentation through inlet cooling and focus on the rising opportunities when these are combined with thermal energy storage. The results show that there is great potential in such systems due to their capability to provide intake conditioning of the gas turbine, decoupled from the ambient conditions. Moreover, latent heat TES have the strongest potential (compared to sensible heat TES) towards integrated inlet conditioning systems, making them a comparable solution to the more conventional cooling methods and uniquely suitable for energy production applications where stabilization of GT air inlet temperature is a requisite. Considering the system’s thermophysical, environmental and economic characteristics, employing TES leads to more than 10% power augmentation.

LES of Swirling Flows in Gas Turbine Combustion Chambers

2004 ◽  
Author(s):  
Bogdan Gherman ◽  
Robert-Zoltan Szasz ◽  
Laszlo Fuchs
Keyword(s):  
Gas Turbine ◽  
Swirling Flows ◽  
Large Eddy Simulations ◽  
Combustion Chambers ◽  
Axial Distribution ◽  
Swirl Angle ◽  
Large Eddy ◽  
Air Mixing ◽  
Inlet Conditions ◽  
Gas Turbine Burner

The flow and mixing in a swirl-stabilized gas-turbine burner is studied by Large Eddy Simulations (LES). Each swirler has a different mass flux and swirl angle. The interaction between neighbouring jets is studied, co-rotating and counter rotating jets are considered. Another issue of importance is related to the jet inlet conditions (e.g. axial distribution and levels of turbulence). In addition to the flow field (using LES) we present results related to fuel/air mixing under different conditions. We show that the LES results can resolve several issues related to the burner that cannot be accounted for by the standard RANS computations.

Radial Swirler Designs for Ultra-Low NOx Gas Turbine Combustion

2008 ◽  
Author(s):  
Gordon E. Andrews ◽  
Nick Escott ◽  
Michael C. Mkpadi
Keyword(s):  
Gas Turbine ◽  
Cross Sections ◽  
Fuel Injection ◽  
Expansion Ratio ◽  
Nox Emissions ◽  
Air Inlet ◽  
Primary Zone ◽  
Air Mixing ◽  
Wall Injection ◽  
Injection Location

Four radial swirler vane passage designs were investigated for low NOx lean well mixed combustion of natural gas at simulated gas turbine primary zone conditions in terms of reference velocities and 600–740K air inlet temperatures at atmospheric pressure. Each radial swirler had eight vane passages and the four passage designs were curved, aerodynamic tapered flat bladed, rectangular and circular passage cross sections. The first two designs had an area that decreased towards the passage outlet and the last two designs were constant area vane passages. The swirler exit diameter d (76mm) to the combustor diameter D (140mm) expansion ratio, D/d, was 1.84. Three methods of fuel injection were investigated: eight single fuel holes per radial vane passage injection, swirler outlet throat 8 hole wall injection and 8 hole radially outward central injection. The results showed that the different radial swirler designs did not have a strong influence on the NOx emissions, compared with the stronger influence of the fuel injection location. All radial vane swirler passage designs gave minimum NOx emissions in the 1–2 ppm range. The radial swirler design influenced which fuel injection location, passage or exit throat wall, gave the lowest NOx emissions. The results were compared with the CPMCP ultra-low NOx emissions concept to show that the present rapid fuel and air mixing radial swirler results are equal to the best premixed low NOx designs.

scholarly journals Indoor Airflow Distribution in Repository Design: Experimental and Numerical Microclimate Analysis of an Archive

Buildings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 152
Author(s):  
Karin Kompatscher ◽  
Rick P. Kramer ◽  
Bart Ankersmit ◽  
Henk L. Schellen
Keyword(s):  
Vertical Gradient ◽  
Building Envelope ◽  
Cfd Modeling ◽  
Indoor Climate ◽  
Ambient Conditions ◽  
Climate Control ◽  
Climate Conditions ◽  
Airflow Distribution ◽  
Air Mixing ◽  
Delay Variations

The majority of cultural heritage is stored in archives, libraries and museum storage spaces. To reduce degradation risks, many archives adopt the use of archival boxes, among other means, to provide the necessary climate control and comply with strict legislation requirements regarding temperature and relative air humidity. A strict ambient indoor climate is assumed to provide adequate environmental conditions near objects. Guidelines and legislation provide requirements for ambient indoor climate parameters, but often do not consider other factors that influence the near-object environment, such as the use of archival boxes, airflow distribution and archival rack placement. This study aimed to provide more insight into the relation between the ambient indoor conditions in repositories and the hygrothermal conditions surrounding the collection. Comprehensive measurements were performed in a case study archive to collect ambient, local and near-object conditions. Both measurements and computational fluid dynamics (CFD) modeling were used to research temperature/relative humidity gradients and airflow distribution with a changing rack orientation, climate control strategy and supply as well as exhaust set-up in a repository. The following conclusions are presented: (i) supplying air from one air handling unit to multiple repositories on different floors leads to small temperature differences between them. Differences in ambient and local climates are noticed; (ii) archival boxes mute and delay variations in ambient conditions as expected—however, thermal radiation from the building envelope may have a large influence on the climate conditions in a box; (iii) adopting night reduction for energy conservation results in an increased influence of the external climate, with adequate insulation, this effect should be mitigated; and (iv) the specific locations of the supply air and extraction of air resulted in a vertical gradient of temperature and insufficient mixing of air, and adequate ventilation strategies should enhance sufficient air mixing in combination with the insulation of external walls, and gradient forming should be reduced.

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