Design for Thermo-Acoustic Stability: Modeling of Burner and Flame Dynamics

2013 ◽  
Author(s):  
Stefanie Bade ◽  
Michael Wagner ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer ◽  
Bruno Schuermans
Keyword(s):  
Optimization Procedure ◽  
Parametric Models ◽  
Design Parameters ◽  
Model Parameters ◽  
Geometrical Parameters ◽  
Flame Dynamics ◽  
Stability Model ◽  
Flame Response ◽  
Burner Design ◽  
Acoustic Stability

A Design for Thermo-Acoustic Stability (DeTAS) procedure is presented, that aims at selecting a most stable burner geometry for a given combustor. It is based on the premise that a thermo-acoustic stability model of the combustor can be formulated and that a burner design exists, which has geometric design parameters that sufficiently influence the dynamics of the flame. Describing the flame dynamics in dependence of the geometrical parameters an optimization procedure involving a linear stability model of the target combustor maximizes the damping and thereby yields the optimal geometrical parameters. To demonstrate the procedure on an existing annular combustor a generic burner design was developed that features a significant variability of dynamical flame response in dependence of two geometrical parameters. In this paper the experimentally determined complex burner acoustics and complex flame responses are described in terms of physics based parametric models with excellent agreement between experimental and model data. It is shown that these model parameters correlate uniquely with the variation of the burner geometrical parameters, allowing to interpolate the model with respect to the geometrical parameters. The interpolation is validated with experimental data.

Design for Thermo-Acoustic Stability: Modeling of Burner and Flame Dynamics

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
S. Bade ◽  
M. Wagner ◽  
C. Hirsch ◽  
T. Sattelmayer ◽  
B. Schuermans
Keyword(s):  
Optimization Procedure ◽  
Parametric Models ◽  
Design Parameters ◽  
Model Parameters ◽  
Geometrical Parameters ◽  
Flame Dynamics ◽  
Stability Model ◽  
Flame Response ◽  
Burner Design ◽  
Acoustic Stability

A design for thermo-acoustic stability (DeTAS) procedure is presented that aims at selecting the most stable burner geometry for a given combustor. It is based on the premise that a thermo-acoustic stability model of the combustor can be formulated and that a burner design exists, which has geometric design parameters that sufficiently influence the dynamics of the flame. Describing the flame dynamics in dependence of the geometrical parameters, an optimization procedure involving a linear stability model of the target combustor, maximizes the damping and thereby yields the optimal geometrical parameters. To demonstrate the procedure on an existing annular combustor a generic burner design was developed that features significant variability of dynamical flame response in dependence of two geometrical parameters. In this paper the experimentally determined complex burner acoustics and complex flame responses are described in terms of physics-based parametric models with excellent agreement between experimental and model data. It is shown that these model parameters correlate uniquely with the variation of the burner geometrical parameters, allowing interpolating the model with respect to the geometrical parameters. The interpolation is validated with experimental data.

Design for Thermo-Acoustic Stability: Procedure and Data Base

2013 ◽  
Author(s):  
Stefanie Bade ◽  
Michael Wagner ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer ◽  
Bruno Schuermans
Keyword(s):  
Data Base ◽  
Optimization Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Flame Dynamics ◽  
Stability Model ◽  
Annular Combustor ◽  
Dynamical Properties ◽  
Burner Design ◽  
Acoustic Stability

A Design for Thermo-Acoustic Stability (DeTAS) procedure is presented, that aims at selecting a most stable burner geometry for a given combustor. It is based on the premise that a thermo-acoustic stability model of the combustor can be formulated and that a burner design exists, which has geometric design parameters that sufficiently influence the dynamics of the flame. Describing the burner and flame dynamics in dependence of the geometrical parameters an optimization procedure involving a linear stability model of the target combustor maximizes the damping and thereby yields the optimal geometrical parameters. To demonstrate the procedure on an existing annular combustor a generic burner design was developed that features two geometrical parameters that can easily be adjusted. To provide the data base for the DeTAS procedure static and dynamical properties of burner and flame were measured for three by three configurations at a fixed operation point. The data is presented and discussed. It is found that the chosen design exhibits a significant variability of the flame dynamics in dependence of the geometrical parameters indicating that a DeTAS should be possible for the targeted annular combustor.

Design for Thermo-Acoustic Stability: Procedure and Database

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
S. Bade ◽  
M. Wagner ◽  
C. Hirsch ◽  
T. Sattelmayer ◽  
B. Schuermans
Keyword(s):  
Linear Stability ◽  
Optimization Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Flame Dynamics ◽  
Stability Model ◽  
Annular Combustor ◽  
Dynamical Properties ◽  
Burner Design ◽  
Acoustic Stability

A design for thermo-acoustic stability (DeTAS) procedure is presented, that aims at selecting a most stable burner geometry for a given combustor. It is based on the premise that a thermo-acoustic stability model of the combustor can be formulated and that a burner design exists, which has geometric design parameters that sufficiently influence the dynamics of the flame. Describing the burner and flame dynamics in dependence of the geometrical parameters an optimization procedure involving a linear stability model of the target combustor maximizes the damping and thereby yields the optimal geometrical parameters. To demonstrate the procedure on an existing annular combustor a generic burner design was developed that features two geometrical parameters that can easily be adjusted. To provide the database for the DeTAS procedure static and dynamical properties of burner and flame were measured for three by three configurations at a fixed operation point. The data is presented and discussed. It is found that the chosen design exhibits a significant variability of the flame dynamics in dependence of the geometrical parameters indicating that a DeTAS should be possible for the targeted annular combustor.

scholarly journals Methods for the Calculation of Thermoacoustic Stability Boundaries and Monte Carlo-Free Uncertainty Quantification

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Georg A. Mensah ◽  
Luca Magri ◽  
Jonas P. Moeck
Keyword(s):  
Monte Carlo ◽  
Uncertainty Quantification ◽  
Gas Turbines ◽  
Network Models ◽  
System Stability ◽  
Model Parameters ◽  
Geometrical Parameters ◽  
Parameter Uncertainties ◽  
Flame Response ◽  
Mode Stability

Thermoacoustic instabilities are a major threat for modern gas turbines. Frequency-domain-based stability methods, such as network models and Helmholtz solvers, are common design tools because they are fast compared to compressible flow computations. They result in an eigenvalue problem, which is nonlinear with respect to the eigenvalue. Thus, the influence of the relevant parameters on mode stability is only given implicitly. Small changes in some model parameters, may have a great impact on stability. The assessment of how parameter uncertainties propagate to system stability is therefore crucial for safe gas turbine operation. This question is addressed by uncertainty quantification. A common strategy for uncertainty quantification in thermoacoustics is risk factor analysis. One general challenge regarding uncertainty quantification is the sheer number of uncertain parameter combinations to be quantified. For instance, uncertain parameters in an annular combustor might be the equivalence ratio, convection times, geometrical parameters, boundary impedances, flame response model parameters, etc. A new and fast way to obtain algebraic parameter models in order to tackle the implicit nature of the problem is using adjoint perturbation theory. This paper aims to further utilize adjoint methods for the quantification of uncertainties. This analytical method avoids the usual random Monte Carlo (MC) simulations, making it particularly attractive for industrial purposes. Using network models and the open-source Helmholtz solver PyHoltz, it is also discussed how to apply the method with standard modeling techniques. The theory is exemplified based on a simple ducted flame and a combustor of EM2C laboratory for which experimental data are available.

Mathematical Modeling and Multi-Objective Optimization of a Mini-Channel Heat Exchanger Via Genetic Algorithm

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Tommaso Selleri ◽  
Behzad Najafi ◽  
Fabio Rinaldi ◽  
Guido Colombo
Keyword(s):  
Genetic Algorithm ◽  
Heat Exchanger ◽  
Multiobjective Optimization ◽  
Pareto Front ◽  
Optimization Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Objective Functions ◽  
Pressure Drops ◽  
Overall Heat Transfer Coefficient

In the present paper a mathematical model for a mini-channel heat exchanger is proposed. Multiobjective optimization using genetic algorithm is performed in the next step in order to obtain a set of geometrical design parameters, leading to minimum pressure drops and maximum overall heat transfer coefficient. Multiobjective optimization procedure provides a set of optimal solutions, called Pareto front, each of which is a trade-off between the objective functions and can be freely selected by the user according to the specifications of the project. A sensitivity analysis is also carried out to study the effects of different geometrical parameters on the considered functions. The whole system has been modeled based on advanced experimental correlations in matlab environment using a modular approach.

scholarly journals Optimized Design of a Novel Hydraulic Propeller Turbine for Low Heads

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 20
Author(s):  
Dario Barsi ◽  
Marina Ubaldi ◽  
Pietro Zunino ◽  
Robert Fink
Keyword(s):  
Design Optimization ◽  
High Efficiency ◽  
Single Point ◽  
Design Procedure ◽  
Optimization Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Practical Case ◽  
Optimized Design ◽  
Starting Point

In the present paper, an optimized design procedure capable of providing the geometry of a high efficiency compact hydraulic propeller turbine for low head is proposed and developed. The turbine preliminary design is based on fundamental turbomachinery mean-line equations and on the employment of statistical correlations, which relate the main geometrical parameters to the fundamental design parameters. The first obtained geometry represents the starting point of an automated aerodynamic single point optimization procedure based on a genetic algorithm generating and updating a wide database of turbine geometries. The approach employs a three-dimensional (3D) Reynolds averaged Navier–Stokes (RANS) solver for the construction of the corresponding database of performance. A meta-model, such as an artificial neural network (ANN), is used to speed up the design optimization process. The procedure has been applied on the practical case of a novel simplified hydraulic propeller turbine prototype for very low heads. The adopted design optimization procedure is able to modify the turbine blade and vane geometries in order to achieve automatically the targeted net head and the maximum for the total to total internal efficiency once diameter, mass flow rate, and rotational speed are assigned.

Computer-Based Design of Disc Brakes by Multi-Objective Form Optimization

2001 ◽  
Author(s):  
Sayed M. Metwalli ◽  
Hesham A. Hegazi
Keyword(s):  
Thermal Stresses ◽  
Optimization Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Objective Functions ◽  
Multi Objective ◽  
Disk Brake ◽  
Disc Brakes ◽  
Present Design ◽  
Computer Based

Abstract This paper is concerned with the application of CAD to design disc brakes using multi-objective form optimization. Temperature and disc (rotor) volume are two competing design objective functions used to obtain the optimum design parameters of disc brakes. The geometrical parameters affecting disk brake design such as the outer and inner disc diameters, disc thickness, pad thickness and pad angle are considered. The exponents of the two competing objective functions are to be optimized for better results. A sensitivity analysis of the two exponents (A and B) is used for this optimization procedure. The design vector for optimizing disc brakes includes the outer disc diameters, diameter ratio, disc thickness, and pad angle. The multi-objective formulation satisfies maximum attained torque; minimum actuating force; minimum thermal stresses; minimum temperature and minimum disc volume. A comparison with two previous optimization results indicates a marked improvement of the present design since previous results did not consider all design parameters or optimized objectives.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

scholarly journals Electrochemical Model-Based Investigation of Thick LiFePO4 Electrode Design Parameters

Modelling ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 259-287
Author(s):  
Robert Franke-Lang ◽  
Julia Kowal
Keyword(s):  
Lithium Ion Batteries ◽  
Porous Electrode ◽  
Lithium Ion ◽  
Size Composition ◽  
Design Parameters ◽  
Model Parameters ◽  
Electrode Structure ◽  
Transport Channel ◽  
Scale Particle ◽  
Electrochemical Model

The electrification of the powertrain requires enhanced performance of lithium-ion batteries, mainly in terms of energy and power density. They can be improved by optimising the positive electrode, i.e., by changing their size, composition or morphology. Thick electrodes increase the gravimetric energy density but generally have an inefficient performance. This work presents a 2D modelling approach for better understanding the design parameters of a thick LiFePO4 electrode based on the P2D model and discusses it with common literature values. With a superior macrostructure providing a vertical transport channel for lithium ions, a simple approach could be developed to find the best electrode structure in terms of macro- and microstructure for currents up to 4C. The thicker the electrode, the more important are the direct and valid transport paths within the entire porous electrode structure. On a smaller scale, particle size, binder content, porosity and tortuosity were identified as very impactful parameters, and they can all be attributed to the microstructure. Both in modelling and electrode optimisation of lithium-ion batteries, knowledge of the real microstructure is essential as the cross-validation of a cellular and lamellar freeze-casted electrode has shown. A procedure was presented that uses the parametric study when few model parameters are known.

Optimization of Turbofan Propulsion Cycle Using a Genetic Algorithm

2010 ◽  
Author(s):  
Adel Ghenaiet
Keyword(s):  
Genetic Algorithm ◽  
Fuel Consumption ◽  
Pressure Ratio ◽  
Engine Performance ◽  
Optimization Procedure ◽  
Specific Fuel Consumption ◽  
High Mass ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Simplifying Assumptions

This paper presents an evolutionary approach as the optimization framework to design for the optimal performance of a high-bypass unmixed turbofan to match with the power requirements of a commercial aircraft. The parametric analysis had the objective to highlight the effects of the principal design parameters on the propulsive performance in terms of specific fuel consumption and specific thrust. The design optimization procedure based on the genetic algorithm PIKAIA coupled to the developed engine performance analyzer (on-design and off-design) aimed at finding the propulsion cycle parameters minimizing the specific fuel consumption, while meeting the required thrusts in cruise and takeoff and the restrictions of temperatures limits, engine size and weight as well as pollutants emissions. This methodology does not use engine components’ maps and operates on simplifying assumptions which are satisfying the conceptual or early design stages. The predefined requirements and design constraints have resulted in an engine with high mass flow rate, bypass ratio and overall pressure ratio and a moderate turbine inlet temperature. In general, the optimized engine is fairly comparable with available engines of equivalent power range.

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