scholarly journals Vortex breakdown of the swirling flow in a Lean Direct Injection burner

2020 ◽  
Vol 32 (12) ◽  
pp. 125118
Author(s):  
Yazhou Shen ◽  
Mohamad Ghulam ◽  
Kai Zhang ◽  
Ephraim Gutmark ◽  
Christophe Duwig
Keyword(s):  
Vortex Breakdown ◽  
Swirling Flow ◽  
Direct Injection ◽  
Lean Direct Injection ◽  
Injection Burner

Large-Eddy Simulation of a Swirl-Stabilized, Lean Direct Injection Spray Combustor

2006 ◽  
Author(s):  
Mehmet Kırtas¸ ◽  
Nayan Patel ◽  
Vaidyanathan Sankaran ◽  
Suresh Menon
Keyword(s):  
Large Eddy Simulation ◽  
Vortex Breakdown ◽  
Direct Injection ◽  
Reacting Flow ◽  
Mean Velocity ◽  
Recirculation Bubble ◽  
Lean Direct Injection ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Recirculation Zones

Large-eddy simulation (LES) of a lean-direct injection (LDI) combustor is reported in this paper. The full combustor and all the six swirl vanes are resolved and both cold and reacting flow simulations are performed. Cold flow predictions with LES indicate the presence of a broad central recirculation zone due to vortex breakdown phenomenon near the dump plane and two corner recirculation zones at the top and bottom corner of the combustor. These predicted features compare well with the experimental non-reacting data. Reacting case simulated a liquid Jet-A fuel spray using a Lagrangian approach. A three-step kinetics model that included CO and NO is used for the chemistry. Comparison of mean velocity field predicted in the reacting LES with experiments shows reasonable agreement. Comparison with the non-reacting case shows that the centerline recirculation bubble is shorter but more intense in the reacting case.

Spectral Analysis of an Aeronautical Lean Direct Injection Burner Through Large Eddy Simulation

2020 ◽  
Author(s):  
M. Carreres ◽  
L. M. García-Cuevas ◽  
J. García-Tíscar ◽  
M. Belmar-Gil
Keyword(s):  
Experimental Data ◽  
Spectral Analysis ◽  
Flow Field ◽  
Large Eddy Simulation ◽  
Swirling Flow ◽  
Direct Injection ◽  
Flow Structures ◽  
Lean Direct Injection ◽  
Eddy Simulation ◽  
Large Eddy

Abstract During the last decades, many efforts have been invested by the scientific community in minimising exhaust emissions from aeronautical gas turbine engines. In this context, many advanced ultra-low NOx combustion concepts, such as the Lean Direct Injection treated in the present study, are being developed to abide by future regulations. Numerical simulations of these devices are usually computationally expensive since they imply a multi-scale problem. In this work, a non-reactive Large Eddy Simulation of a gaseous-fuelled, radial-swirled Lean-Direct Injection (LDI) combustor has been carried out through the OpenFOAM Computational Fluid Dynamics (CFD) code by solving the complete inlet flow path through the swirl vanes and the combustor. The geometry considered is the gaseous configuration of the CORIA LDI combustor, for which detailed measurements are available. Macroscopical analysis of the main turbulent features related to the swirling flow and the generated Central Recirculation Zone (CRZ) are well established in the literature. Nevertheless, a more in-depth characterization is still required in this area of active research since theory and experimental data are not yet able to predict which unstable mode dominates the flow. This work aims at using Large Eddy Simulation for a complete characterisation of the unsteady flow structures generated within the combustion chamber of a gaseous methane injection immersed in a strong non-reactive swirling flow field. To do so, a spectral analysis of the flow field is performed to identify the frequency, intensity and instabilities associated to the phenomena occurring at the swirler outlet region. A coherent structure known as Precessing Vortex Core (PVC) is identified both at the inner and the outer shear layers, resulting in a periodic disturbance of the pressure and velocity fields. The pressure and velocity fluctuations predicted by the CFD code are used to compute the spectral signatures through the Sound Pressure Level (SPL) amplitude at multiple locations. This allows investigating both the complex behaviour of the PVC and its associated acoustic phenomena. The acoustic characteristics computed by the numerical model are first validated qualitatively by comparing the spectrum with available experimental data. In this way, the use of dimensionless numbers to characterise the most energetic structures is coherent with the experimental observations and the characteristics of the PVC. Then, the numerical identification of the main acoustic modes in the chamber through Dynamic Mode Decomposition (DMD) allows overcoming the Fast Fourier Transform (FFT) shortcomings and better understanding the propagation of the hydrodynamic instability perturbations. This investigation on the main non-reacting swirling flow structures inside the combustor provides a suitable background for further studies on combustion instability mechanisms.

Spectral Analysis of an Aeronautical Lean Direct Injection Burner Through Large Eddy Simulation

2021 ◽  
Author(s):  
Marcos Carreres ◽  
Luis Miguel Garcia-Cuevas ◽  
Jorge Garc\xeda-T\xedscar ◽  
Mario Belmar
Keyword(s):  
Spectral Analysis ◽  
Large Eddy Simulation ◽  
Direct Injection ◽  
Lean Direct Injection ◽  
Eddy Simulation ◽  
Injection Burner ◽  
Large Eddy

Study of Swirling Air Flow Characteristics in a Lean Direct Injection Combustor

2010 ◽  
Author(s):  
Dipanjay Dewanji ◽  
Arvind G. Rao ◽  
Mathieu Pourquie ◽  
Jos P. van Buijtenen
Keyword(s):  
Numerical Model ◽  
Flow Field ◽  
Swirling Flow ◽  
Direct Injection ◽  
Flow Characteristics ◽  
Single Element ◽  
Complex Flow ◽  
Flow Passage ◽  
Lean Direct Injection ◽  
Entire Flow

This paper investigates the non-reacting aerodynamic flow characteristics in Lean Direct Injection (LDI) combustors. The RANS modeling is used to simulate the turbulent, non-reacting, and confined flow field associated with a single-element and a nine-element LDI combustor. The results obtained from the simulation are compared with some experimental data available in literature. The numerical model, which is in accordance with an experimental combustor, consists of an air swirler with 6 helical axial vanes of 60 degree vane angle and a converging-diverging duct, extending in a square flame tube. The numerical model covers the entire flow passage, including the highly swirling flow passage through the swirler vanes, and the combustion chamber. Simulation has been performed with a low Reynolds number realizable k-ε model and a Reynolds stress turbulence model. It is observed that the computational model is able to predict the central re-circulation zones (CTRZ), the corner recirculation zones, and the complex flow field associated with the adjacent swirlers with reasonable accuracy. The computed velocity components for the single-element case show that the flow field is similar to the experimental observations.

scholarly journals Modeling gaseous non-reactive flow in a lean direct injection gas turbine combustor through an advanced mesh control strategy

2020 ◽  
Vol 234 (11) ◽  
pp. 1788-1810
Author(s):  
R Payri ◽  
R Novella ◽  
M Carreres ◽  
M Belmar-Gil
Keyword(s):  
Gas Turbine ◽  
Adaptive Mesh Refinement ◽  
Swirling Flow ◽  
Direct Injection ◽  
Mesh Refinement ◽  
Adaptive Mesh ◽  
Experimental Database ◽  
Lean Direct Injection ◽  
Multi Scale ◽  
Large Eddy

Fuel efficiency improvement and harmful emissions reduction are the main motivations for the development of gas turbine combustors. Numerical computational fluid dynamics (CFD) simulations of these devices are usually computationally expensive since they imply a multi-scale problem. In this work, gaseous non-reactive unsteady Reynolds-Averaged Navier–Stokes and large eddy simulations of a gaseous-fueled radial-swirled lean direct injection combustor have been carried out through CONVERGE™ CFD code by solving the complete inlet flow path through the swirl vanes and the combustor. The geometry considered is the gaseous configuration of the CORIA lean direct injection combustor, for which detailed measurements are available. The emphasis of the work is placed on the demonstration of the CONVERGE™ applicability to the multi-scale gas turbine engines field and the determination of an optimal mesh strategy through several grid control tools (i.e., local refinement, adaptive mesh refinement) allowing the exploitation of its automatic mesh generation against traditional fixed mesh approaches. For this purpose, the normalized mean square error has been adopted to quantify the accuracy of turbulent numerical statistics regarding the agreement with the experimental database. Furthermore, the focus of the work is to study the behavior when coupling several large eddy simulation sub-grid scale models (i.e., Smagorinsky, Dynamic Smagorinsky, and Dynamic Structure) with the adaptive mesh refinement algorithm through the evaluation of its specific performances and predictive capabilities in resolving the spatial-temporal scales and the intrinsically unsteady flow structures generated within the combustor. This investigation on the main non-reacting swirling flow characteristics inside the combustor provides a suitable background for further studies on combustion instability mechanisms.

Numerical Study of Non-Reacting and Reacting Flow Characteristics in a Lean Direct Injection Combustor

2011 ◽  
Author(s):  
Dipanjay Dewanji ◽  
Arvind G. Rao ◽  
Mathieu Pourquie ◽  
Jos P. van Buijtenen
Keyword(s):  
Flow Field ◽  
Swirling Flow ◽  
Numerical Study ◽  
Reverse Flow ◽  
Direct Injection ◽  
Flow Characteristics ◽  
Droplet Breakup ◽  
Reacting Flow ◽  
Lean Direct Injection ◽  
Wide Range

The Lean Direct Injection (LDI) combustion concept has been of active interest due to its potential for low emissions under a wide range of operational conditions. This might allow the LDI concept to become the next generation gas-turbine combustion scheme for aviation engines. Nevertheless, the underlying unsteady phenomena, which are responsible for low emissions, have not been widely investigated. This paper reports a numerical study on the characteristics of the non-reacting and reacting flow field in a single-element LDI combustor. The solution for the non-reacting flow captures the essential aerodynamic flow characteristics of the LDI combustor, such as the reverse flow regions and the complex swirling flow structures inside the swirlers and in the neighborhood of the combustion chamber inlet, with reasonable accuracy. A spray model is introduced to simulate the reacting flow field. The reaction of the spray greatly influences the gas-phase velocity distribution. The heat release effect due to combustion results in a significantly stronger and compact reverse flow zone as compared to that of the non-reacting case. The inflow spray is specified by the Kelvin-Helmholtz breakup model, which is implemented in the Reynolds-Averaged Navier Stokes (RANS) code. The results show a strong influence of the high swirling flow field on liquid droplet breakup and flow mixing process, which in turn could explain the low-emission behavior of the LDI combustion concept.

Multi-Swirl Lean Direct Injection Burner for Enhanced Combustion Stability and Low Pollutant Emissions

2017 ◽  
Author(s):  
V. Deepika ◽  
S. R. Chakravarthy ◽  
T. M. Muruganandam ◽  
N. Raja Bharathi
Keyword(s):  
Pressure Drop ◽  
Gas Turbine ◽  
Direct Injection ◽  
Combustion Stability ◽  
Pollutant Emissions ◽  
Lean Direct Injection ◽  
Unburned Hydrocarbon ◽  
Injection Burner ◽  
Efficient Combustion ◽  
Flame Flashback

Control of emissions is a big challenge plaguing the gas turbine industry for years. This necessitates new combustor designs addressing the problem. This paper discusses the characterization of a novel burner* employing Lean Direct Injection (LDI) technology for reduced pollutant emissions and improved combustion. The burner is an array of multiple swirlers arranged closely, facilitating distributed mixing of fuel and air at each swirler throughout the length of the burner. This results in a uniform and rapid mixing, thus eliminating hot spots and enabling efficient combustion. The burner thus developed is capable of operating at very lean conditions of fuel, leading to overall temperatures being low. The burner is characterized in terms of lean blow out equivalence ratio, pressure drop, average exit temperature of the burnt mixture, pattern factor and emissions — CO, CO2, unburned hydrocarbon (UHC), NOx and soot. Results show very low NOx emissions. Enhanced combustion also results in reduction in overall emissions. It overcomes the drawback of flame flashback encountered in lean premixed pre-vaporized concept. LDI is also less susceptible to combustion instability. Pressure drop across the burner is observed to be very less compared to the conventional gas turbine combustors. Thus, this concept of multi-swirl LDI burner can be a potential contender to be employed in the combustors of gas turbine engines.

Combustion Dynamics Behavior in a Single-Element Lean Direct Injection (LDI) Gas Turbine Combustor

2014 ◽  
Author(s):  
Cheng Huang ◽  
Rohan Gejji ◽  
William Anderson ◽  
Changjin Yoon ◽  
Venkateswaran Sankaran
Keyword(s):  
Gas Turbine ◽  
Direct Injection ◽  
Single Element ◽  
Gas Turbine Combustor ◽  
Combustion Dynamics ◽  
Lean Direct Injection
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