Accurate Inlet Boundary Conditions to Capture Combustion Chamber and Turbine Coupling with Large-Eddy Simulation

2021 ◽  
Author(s):  
Benjamin Martin ◽  
Florent Duchaine ◽  
Laurent Y.M. Gicquel ◽  
Nicolas Odier ◽  
Jerome Dombard
Keyword(s):  
Combustion Chamber ◽  
Interface Plane ◽  
Fully Integrated ◽  
Integrated Simulation ◽  
Eddy Simulation ◽  
Reference Simulation ◽  
Large Eddy ◽  
Recorded Data ◽  
Proper Orthogonal ◽  
Inlet Boundary Condition

Abstract The coupling between different components of a turbomachinery is becoming more widely studied especially by use of Computational Fluid Dynamics. Such simulations are of particular interest especially at the interface between a combustion chamber and a turbine, for which the prediction of the migration of hotspots generated in the chamber is of paramount importance for performance and life-duration issues. The objective of the present study is to investigate available solutions to perform isolated simulations while taking into account the effect of multi-component coupling. Investigations presented in the paper focus on the FACTOR configuration. The fist step of the proposed method is to record conservative variables solved by the LES code at the interface plane between the chamber and the turbine of a reference simulation. Then, using the Spectral Proper Orthogonal Decomposition method, the recorded data is analysed and can be partially reconstructed using different numbers of frequencies. Using the partial reconstructions, it is then possible to replicate a realistic inlet boundary condition for isolated turbine simulations with both velocity and temperature fluctuations, while reducing the storage cost compared to the initial database. The integrated simulation is then compared to the isolated simulations as well as against simulations making use of averaged quantities with or without synthetic turbulence injection at their inlet. The isolated simulations for which the inlet condition is reconstructed with a large number of frequencies show very good agreement with the fully integrated simulation compared to the typical isolated simulation using average quantities at the inlet.

Accurate Inlet Boundary Conditions to Capture Combustion Chamber and Turbine Coupling With Large-Eddy Simulation

2021 ◽  
Author(s):  
Benjamin Martin ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Nicolas Odier ◽  
Jérôme Dombard
Keyword(s):  
Boundary Conditions ◽  
Combustion Chamber ◽  
Radial Profile ◽  
Point Of View ◽  
Interface Plane ◽  
Fully Integrated ◽  
Integrated Simulation ◽  
Eddy Simulation ◽  
Reconstructed Signal ◽  
Recorded Data

Abstract The coupling between different components of a turbomachinery is becoming more widely studied especially by use of Computational Fluid Dynamics. Such simulations are of particular interest especially at the interface between a combustion chamber and a turbine, for which the prediction of the migration of hotspots generated in the chamber is of paramount importance for performance and life-duration issues. Despite this need for fully integrated simulations, typical turbomachinery simulations however often only consider isolated components with either time-averaged constant value, radial profile or least frequently 2D maps imposed at their inlet boundaries preventing any accurate two-way coupling. The objective of the present study is to investigate available solutions to perform isolated simulations while taking into account the effect of multi-component coupling. Investigations presented in the paper focus on the FACTOR configuration. The fist step of the proposed method is to record conservative variables solved by the LES code at the interface plane between the chamber and the turbine of a reference simulation. Then, using the Spectral Proper Orthogonal Decomposition (SPOD) method, the recorded data is analysed and can be partially reconstructed using different numbers of frequencies. Using the partial reconstructions, it is then possible to replicate a realistic inlet boundary condition for isolated turbine simulations with both velocity and temperature fluctuations, while reducing the storage cost compared to the initial database. The integrated simulation is then compared to the isolated simulations as well as against simulations making use of averaged quantities with or without synthetic turbulence injection at their inlet. The isolated simulations for which the inlet condition is reconstructed with a large number of frequencies show very good agreement with the fully integrated simulation compared to the typical isolated simulation using average quantities at the inlet. As expected, decreasing the number of frequencies in the reconstructed signal deteriorates the accuracy of the resulting signal compared to the full recorded database. However, isolated simulations with a low number of frequencies still perform better than standard boundary conditions, especially from an aero-thermal point of view.

scholarly journals Towards the Large-Eddy Simulation of a full engine: Integration of a 360 azimuthal degrees fan, compressor and combustion chamber. Part I: Methodology and initialisation

2021 ◽  
pp. 1-16
Author(s):  
Carlos Pérez Arroyo ◽  
Jérôme Dombard ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Benjamin Martin ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Combustion Chamber ◽  
Computational Cost ◽  
Thermodynamic Cycle ◽  
Turbine Engine ◽  
Fully Integrated ◽  
Integrated Simulation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
The Impact

Optimising the design of aviation propulsion systems using computational fluid dynamics is essential to increase their efficiency and reduce pollutant as well as noise emissions. Nowadays, and within this optimisation and design phase, it is possible to perform meaningful unsteady computations of the various components of a gas-turbine engine. However, these simulations are often carried out independently of each other and only share averaged quantities at the interfaces minimising the impact and interactions between components. In contrast to the current state-of-the-art, this work presents a 360 azimuthal degrees large-eddy simulation with over 2100 million cells of the DGEN-380 demonstrator engine enclosing a fully integrated fan, compressor and annular combustion chamber at take-off conditions as a first step towards a high-fidelity simulation of the full engine. In order to carry such a challenging simulation and reduce the computational cost, the initial solution is interpolated from stand-alone sectoral simulations of each component. In terms of approach, the integrated mesh is generated in several steps to solve potential machine dependent memory limitations. It is then observed that the 360 degrees computation converges to an operating point with less than 0.5% difference in zero-dimensional values compared to the stand-alone simulations yielding an overall performance within 1% of the designed thermodynamic cycle. With the presented methodology, convergence and azimuthally decorrelated results are achieved for the integrated simulation after only 6 fan revolutions.

Wake-Airfoil Interaction as Broadband Noise Source: A Large-Eddy Simulation Study

2005 ◽  
Vol 4 (1-2) ◽  
pp. 93-115 ◽  
Author(s):  
Jérôme Boudet ◽  
Nathalie Grosjean ◽  
Marc C. Jacob
Keyword(s):  
Large Eddy Simulation ◽  
Particle Image ◽  
Broadband Noise ◽  
Far Field ◽  
Acoustic Analogy ◽  
Eddy Simulation ◽  
Naca0012 Airfoil ◽  
Image Velocimetry ◽  
Large Eddy ◽  
Proper Orthogonal

A large-eddy simulation is carried out on a rod-airfoil configuration and compared to an accompanying experiment as well as to a RANS computation. A NACA0012 airfoil (chord c = 0.1 m) is located one chord downstream of a circular rod (diameter d = c/10, Red = 48 000). The computed interaction of the resulting sub-critical vortex street with the airfoil is assessed using averaged quantities, aerodynamic spectra and proper orthogonal decomposition (POD) of the instantaneous flow fields. Snapshots of the flow field are compared to particle image velocimetry (PIV) data. The acoustic far field is predicted using the Ffowcs Williams & Hawkings acoustic analogy, and compared to the experimental far field spectra. The large-eddy simulation is shown to accurately represent the deterministic pattern of the vortex shedding that is described by POD modes 1 & 2 and the resulting tonal noise also compares favourably to measurements. Furthermore higher order POD modes that are found in the PIV data are well predicted by the computation. The broadband content of the aerodynamic and the acoustic fields is consequently well predicted over a large range of frequencies ([0 kHz; 10 kHz]).

Integrated Large Eddy Simulation of Combustor and Turbine Interactions: Effect of Turbine Stage Inlet Condition

2017 ◽  
Author(s):  
Florent Duchaine ◽  
Jérôme Dombard ◽  
Laurent Gicquel ◽  
Charlie Koupper
Keyword(s):  
Large Eddy Simulation ◽  
Combustion Chamber ◽  
Rotor Blade ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Stator Vane ◽  
Specific Configuration ◽  
Inlet Conditions

To study the effects of combustion chamber dynamics on a turbine stage aerodynamics and thermal loads, an integrated Large-Eddy Simulation of the FACTOR combustion chamber simulator along with its high pressure turbine stage is performed and compared to a standalone turbine stage computation operated under the same mean conditions. For this specific configuration, results illustrate that the aerodynamic expansion of the turbine stage is almost insensitive to the inlet turbulent conditions. However, the temperature distribution in the turbine passages as well as on the stator vane and rotor blade walls are highly impacted by these inlet conditions: underlying the importance of inlet conditions in turbine stage computations and the potential of integrated combustion chamber / turbine simulations in such a context.

Large-Eddy Simulation of an Integrated High-Pressure Compressor and Combustion Chamber of a Typical Turbine Engine Architecture

2020 ◽  
Author(s):  
Carlos Pérez Arroyo ◽  
Jérôme Dombard ◽  
Florent Duchaine ◽  
Laurent Gicquel ◽  
Nicolas Odier ◽  
...  
Keyword(s):  
High Pressure ◽  
Large Eddy Simulation ◽  
Combustion Chamber ◽  
High Amplitude ◽  
Turbine Engine ◽  
Eddy Simulation ◽  
High Pressure Compressor ◽  
Large Eddy ◽  
Pressure Perturbations ◽  
Pressure Compressor

Abstract The design optimization of aviation propulsion systems by means of computational fluid dynamics is key to increase their efficiency and reduce pollutant and noise emissions. The recurrent increase in available computing power allows nowadays to perform unsteady high-fidelity computations of the different components of a gas turbine. However, these simulations are often made independently of each other and they only share average quantities at interfaces. In this work, the methodology and first results for a sectoral large-eddy simulation of an integrated high-pressure compressor and combustion chamber of a typical turbine engine architecture is proposed. In the simulation, the compressor is composed of one main blade and one splitter blade, two radial diffuser vanes and six axial diffuser vanes. The combustion chamber is composed of the contouring casing, the flame-tube and a T-shaped vaporizer. This integrated computation considers a good trade-off between accuracy of the simulation and affordable CPU cost. Results are compared between the stand-alone combustion chamber simulation and the integrated one in terms of global, integral and average quantities. It is shown that pressure perturbations generated by the interaction of the impeller blades with the diffuser vanes are propagated through the axial diffuser and enter the combustion chamber through the dilution holes and the vaporizer. Due to the high amplitude of the pressure perturbations, several variables are perturbed at the blade-passing frequency and multiples. This is also reflected on combustion where two broadband peaks appear for the global heat release.

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