CFD Modeling of Flame Structures in a Gas Turbine Combustion Reactor: Velocity, Temperature, and Species Distribution

2017 ◽  
Vol 15 (4) ◽  
Author(s):  
Alireza Bahramian ◽  
Mozhdeh Maleki ◽  
Bijan Medi
Keyword(s):  
Temperature Profile ◽  
Gas Turbine ◽  
Cfd Simulation ◽  
Flame Structure ◽  
Combustion Process ◽  
Three Dimensional ◽  
Species Distributions ◽  
Kinetic Mechanism ◽  
Cfd Modeling ◽  
Laser Measurements

Abstract This paper presents the computational fluid dynamics (CFD) simulation of a gas turbine combustor with methane-air fuel at atmospheric pressure. The velocity fields, temperature profile and species distributions have been numerically studied. The mathematical combustion models, namely Eddy Dissipation Concept (EDC) model coupled with detailed kinetic mechanism, and Finite Rate/Eddy Dissipation (FR-ED) model coupled with a simple global kinetic mechanism, have been used in numerical analysis considering a two-step oxy-combustion reaction kinetics model. Moreover, a series of CFD results with consideration of EDC model have been obtained by two- and three-dimensional simulations. An error analysis showed that the 3-D simulation with EDC model can accurately predict the velocity components, temperature profile, and species distributions of the combustion process and allow detailed investigation of the flame structure. The CFD results are in agreement with the experimental data obtained from laser measurements.

The 3-D Structure of Swirl-Stabilized Flames in a Lean Premixed Multi-Nozzle Can Combustor

2015 ◽  
Author(s):  
Janith Samarasinghe ◽  
Stephen J. Peluso ◽  
Bryan D. Quay ◽  
Domenic A. Santavicca
Keyword(s):  
Gas Turbine ◽  
Tomographic Reconstruction ◽  
Flame Structure ◽  
Combustion Process ◽  
Three Dimensional ◽  
Static Stability ◽  
Dimensional Structure ◽  
Reconstruction Technique ◽  
Flame Stability ◽  
The Relationship

Flame structure is an important aspect of the combustion process which must be considered in the design of gas turbine combustors as it can have a significant effect on the combustor’s static stability (blowoff) and dynamic stability (combustion instability). The relationship between flame structure and flame stability has been studied extensively in single-nozzle combustors. However, relatively few studies have been conducted in multi-nozzle combustor configurations typical of actual gas turbine combustion systems. In this paper, a chemiluminescence-based tomographic reconstruction technique is used to obtain three-dimensional images of the flame structure in a laboratory-scale five-nozzle can combustor. The images reveal the complex three-dimensional structure of this multi-nozzle flame, as well as, the effects of interacting swirling flows, flame-flame interactions and flame-wall interactions on flame structure.

The Three-Dimensional Structure of Swirl-Stabilized Flames in a Lean Premixed Multinozzle Can Combustor

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Janith Samarasinghe ◽  
Stephen J. Peluso ◽  
Bryan D. Quay ◽  
Domenic A. Santavicca
Keyword(s):  
Gas Turbine ◽  
Tomographic Reconstruction ◽  
Flame Structure ◽  
Combustion Process ◽  
Three Dimensional ◽  
Static Stability ◽  
Dimensional Structure ◽  
Reconstruction Technique ◽  
Three Dimensional Structure ◽  
The Relationship

Flame structure can have a significant effect on a combustor's static stability (resistance to blowoff) and dynamic stability (combustion instability) and therefore is an important aspect of the combustion process that must be taken into account in the design of gas turbine combustors. While the relationship between flame structure and flame stability has been studied extensively in single-nozzle combustors, relatively few studies have been conducted in multinozzle combustor configurations typical of actual gas turbine combustion systems. In this paper, a chemiluminescence-based tomographic reconstruction technique is used to obtain three-dimensional images of the flame structure in a laboratory-scale five-nozzle can combustor. Analysis of the 3D images reveals features of the complex, three-dimensional structure of this multinozzle flame. Effects of interacting swirling flows, flame–flame interactions, and flame–wall interactions on the flame structure are also discussed.

Model Simulation and Design Optimization of a Can Combustor with Methane/Syngas Fuels for a Micro Gas Turbine

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Chi-Rong Liu ◽  
Ming-Tsung Sun ◽  
Hsin-Yi Shih
Keyword(s):  
Gas Turbine ◽  
Turbulent Flows ◽  
Film Cooling ◽  
Fuel Injection ◽  
Model Simulation ◽  
Combustion Process ◽  
Three Dimensional ◽  
Future Application ◽  
Detailed Chemical Kinetics ◽  
Micro Gas Turbine

Abstract The design and model simulation of a can combustor has been made for future syngas combustion application in a micro gas turbine. An improved design of the combustor is studied in this work, where a new fuel injection strategy and film cooling are employed. The simulation of the combustor is conducted by a computational model, which consists of three-dimensional, compressible k-ε model for turbulent flows and PPDF (Presumed Probability Density Function) model for combustion process invoking a laminar flamelet assumption generated by detailed chemical kinetics from GRI 3.0. Thermal and prompt NOx mechanisms are adopted to predict the NO formation. The modeling results indicated that the high temperature flames are stabilized in the center of the primary zone by radially injecting the fuel inward. The exit temperatures of the modified can combustor drop and exhibit a more uniform distribution by coupling film cooling, resulting in a low pattern factor. The combustion characteristics were then investigated and the optimization procedures of the fuel compositions and fuel flow rates were developed for future application of methane/syngas fuels in the micro gas turbine.

Development and Validation of an Ignition Model for SI Engines

2006 ◽  
Author(s):  
Stefania Falfari ◽  
Gian Marco Bianchi
Keyword(s):  
Cfd Simulation ◽  
Combustion Process ◽  
Three Dimensional ◽  
Electrical Energy ◽  
Combustion Model ◽  
Test Case ◽  
Ignition Process ◽  
Mean Flow ◽  
Flame Kernel ◽  
Si Engines

In SI engines the ignition process strongly affects the combustion process. Its accurate modelling becomes a key issue for a design-oriented CFD simulation of the combustion process. Different approaches to simulate ignition have been proposed. The common base is decoupling the physics related to the very first ignition phase when a plasma is formed from that of the development of the flame kernel. The critical point of ignition models is related to the capability of representing the effect of ignition system characteristics, the criterion used for flame deposit and the initialisation of the combustion model. This paper aims to present and validates extensively an ignition model suited for CFD calculation of premixed combustion. The ignition model implemented in a customized version of the Kiva 3 code is coupled with ECFM Flamelet combustion model. The ignition model simulates the plasma/kernel expansion based on a lump evaluation of main ignition processes (i.e., breakdown, arc-phase and glow phase). A double switch criterion based on physical and numerical consideration is used to switch to the main combustion model. The Herweg and Maly experimental test case has been used to check the model capability. In particular, two different ignition systems having different amount of electrical energy released during spark discharge are considered. Comparisons with experimental results allowed testing the model with respect to its capability to reproduce the effects of mixture equivalence ratio, mean flow, turbulence and spark energy on flame kernel development as never done before in three-dimensional RANS CFD combustion modelling of premixed flames.

Three-Dimensional Flamelet Simulation of Polycyclic Aromatic Hydrocarbons Formation in DI-Diesel Engines

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Beijing Zhong ◽  
Shuai Dang ◽  
Jun Xi
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Numerical Simulations ◽  
Aromatic Hydrocarbons ◽  
Direct Injection ◽  
Combustion Process ◽  
Three Dimensional ◽  
Kinetic Mechanism ◽  
Flamelet Model ◽  
Polycyclic Aromatic ◽  
Reduced Kinetic Mechanism

In this study, numerical simulations for an n-heptane fueled Chaochai 6102bzl direct injection diesel engine are performed in order to predict the chemical details of the combustion process and resulting polycyclic aromatic hydrocarbons (such as benzene, naphthalene, phenanthrene and pyrene) formation. The diesel geometry and reduced kinetic mechanism of n-heptane oxidation, which includes only 86 reactions and 57 species, have been developed and incorporated into the computational fluid dynamics code, FLUENT. The diesel unsteady laminar flamelet model, turbulence model and spray model have been employed in the numerical simulations. The numerical simulation results showed that the polycyclic aromatic hydrocarbons were firstly increased with the increase of diesel crank angel and then decreased, which was mostly located at the bottom of diesel combustion chamber wall.

CFD Assisted Design of Micro GT Combustor

2009 ◽  
Author(s):  
Yeshayahou Levy ◽  
Vladimir Erenburg ◽  
Yakov Goldman ◽  
Valery Sherbaum ◽  
Vitaly Ovcharenko
Keyword(s):  
Heat Transfer ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Three Dimensional ◽  
Heat Radiation ◽  
Working Fluid ◽  
Stoichiometric Ratio ◽  
Three Dimensional Model ◽  
Successful Operation ◽  
Predicted Values

The work presents the development of a micro-combustor design, where the combustion process was simulated by CFD and tested experimentally. The inner diameter of the first model was 5.5 mm, the exit diameter 2.5 mm, and the length 24.5 mm. The designed heat release was 200W. Some modifications of the microcombustor were studied. Three-dimensional model for combustion simulations was used. The ‘conjugate heat transfer’ methodology, based on a simultaneous solution of the heat transfer equations for gas and combustor walls, coupled with equations for the working fluid, enabled the prediction of the combustor wall temperatures. To check model convergence 2 simulations with different number of cells were carried out. Effect of heat radiation was also studied by the CFD simulation. The fuel is methane and stoichiometric ratio was simulated. Reactive flow calculations were carried out with a two-step reaction. The analysis of the simulated results was based on the obtained velocity profiles, concentration and temperature distributions within the liner. Preliminary simulations showed that the first combustor design had inefficient combustion. The reason was poor mixing of methane and air inside the mixing chamber and deterioration of the combustion by dilution holes. Consequently, the combustor design was modified and simulated. The simulation showed that the modification significantly improved mixing and combustion process and better combustion was provided. Due to complexity associated with performing combustion experiments in such small dimensions, only limited data could be recorded. A small combustor was manufactured and tests and demonstrated its successful operation. Measurements of temperature and optical UV-VIS-IR - emissions at the combustor exit were obtained. The experimental and simulation results are compared and a good qualitative agreement was found between the experiments and the predicted values.

scholarly journals Assessment and Prediction of Air Entrainment and Geyser Formation in a Bottom Outlet: Field Observations and CFD Simulation

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 203
Author(s):  
James Yang ◽  
Penghua Teng ◽  
Junhu Nan ◽  
Shicheng Li ◽  
Anders Ansell
Keyword(s):  
Water Flow ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Cfd Modeling ◽  
Two Phase ◽  
Gate Operation ◽  
Flow Features ◽  
Air Pockets ◽  
Bottom Outlet

Air entrainment at the intake of a bottom outlet often gives rise to air pockets in its conduit and formation of geysers. The outlet in question comprises a bulkhead gate, gate shaft, horizontal conduit, and exit. Operations show that it suffers from appreciable flow fluctuations and blowouts in the tailwater, which leads to gate operation restrictions. For the purpose of understanding the hydraulic phenomenon, both prototype discharge tests and three-dimensional computational fluid dynamics (CFD) modeling of two-phase flows are performed. The operational focus of the facility are small and large gate openings. The CFD results reveal that, with air entrained in the gate shaft, continual breakup and coalescence of air bubbles in the conduit typify the flow. At small openings below 1 meter, the air–water flow is characterized by either distinct blowouts of regular frequency or continuous air release. In terms of geyser behaviors inclusive of frequency, the agreement is good between field and numerical studies. At large openings, the gate becomes fully submerged, and the flow is discharged without air entrainment and blowouts. The paper showcases the air–water flow features in a typical bottom outlet layout in Sweden, which is intended to serve as an illustration of the study procedure for other similar outlets.

Combustion Characteristics of a Can Combustor With a Rotating Casing for an Innovative Micro Gas Turbine

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Hsin-Yi Shih ◽  
Chi-Rong Liu
Keyword(s):  
Gas Turbine ◽  
Flame Structure ◽  
Three Dimensional ◽  
Combustion Efficiency ◽  
Swirling Flows ◽  
Combustion Characteristics ◽  
Maximum Speed ◽  
Flow Angle ◽  
Rotating Speed ◽  
Micro Gas Turbine

A can type combustor with a rotating casing for an innovative micro gas turbine has been modeled, and the combustion characteristics were investigated. The simulations were performed using commercial code STAR-CD, in which a three-dimensional compressible k-ε turbulent flow model and a one-step overall chemical reaction between methane/air were used. The results include the detailed flame structure at different rotation speeds of outside casing, ranging from stationary to the maximum speed of 58,000 rpm of the design point. The airflows are baffled when entering the combustor through the linear holes due to the centrifugal force caused by the rotating casing, and the inlet flow angle is inclined. When the rotation is in the opposite direction of the swirling flows driven by the designed swirler, a shorter but broader recirculation zone and a concave shape flame are found at a higher rotating speed. At maximum rotating speed, the swirling flows are dominated by the rotating flows caused by the casing, especially downstream of the combustor. The combustor performance was also analyzed, indicating a higher combustion efficiency and higher exit temperature when the casing rotates, which benefits the performance of the gas turbine, but the cooling and possible hot spots for turbines are the primary concerns.

CFD Modeling of Cross Corrugated Microturbine Recuperator

2003 ◽  
Author(s):  
Jirˇi´ Hejcˇi´k ◽  
Miroslav Ji´cha
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Gas Turbine ◽  
Cfd Simulation ◽  
Hydraulic Performance ◽  
Cfd Modeling ◽  
Surface Type ◽  
Pressure Drops

The CFD code STAR CD was used to assess the thermal and hydraulic performance of a primary surface type gas turbine recuperator, with Cross Corrugated (CC) surface. The main goal of CFD modeling was to evaluate heat transfer and pressure drops predicted by the 1D methodology and thus to verify the recuperator efficiency. Two computational domains were made. The first for heat transfer and pressure drops simulation in the recuperator core and the latter for pressure drops predicted at the inlet and outlet ports. Details of the recuperator core, computational domains and the boundary conditions for CFD simulation as well as relevant results are presented.

scholarly journals Design and development of combustion chambers for gas turbine engines based on calculations of various levels of complexity

2021 ◽  
Vol 20 (3) ◽  
pp. 7-23
Author(s):  
Y. B. Aleksandrov ◽  
T. D. Nguyen ◽  
B. G. Mingazov
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Gas Flow ◽  
Combustion Process ◽  
Three Dimensional ◽  
Numerical Calculations ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Combustion Chambers ◽  
Flame Tube

The article proposes a method for designing combustion chambers for gas turbine engines based on a combination of the use of calculations in a one-dimensional and three-dimensional formulation of the problem. This technique allows you to quickly design at the initial stage of creating and development of the existing combustion chambers using simplified calculation algorithms. At the final stage, detailed calculations are carried out using three-dimensional numerical calculations. The method includes hydraulic calculations, on the basis of which the distribution of the air flow passing through the main elements of the combustion chamber is determined. Then, the mixing of the gas flow downstream of the flame tube head and the air passing through the holes in the flame tube is determined. The mixing quality determines the distribution of local mixture compositions along the length of the flame tube. The calculation of the combustion process is carried out with the determination of the combustion efficiency, temperature, concentrations of harmful substances and other parameters. The proposed method is tested drawing on the example of a combustion chamber of the cannular type. The results of numerical calculations, experimental data and values obtained using the proposed method for various operating modes of the engine are compared.

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