Active Flow and Combustion Control 2021: Papers Contributed to the Conference “Active Flow and Combustion Control 2021”, September 28–29, 2021, ... Mechanics and Multidisciplinary Design, 152)

Description

The book reports on the latest theoretical and experimental findings in the field of active flow and combustion control, in the context of energy conversion for power and propulsion systems. It covers new developments in actuator technology and sensing, robust and optimal open- and closed-loop control, model reduction for control purposes, and unsteady turbine cooling and performance, among other relevant topics.  Gathering contributions to the Active Flow and Combustion Control (AFCC 2021), held virtually on September 28-29, 2021, from the Technische Universität Berlin, Germany, this book describes research that has been carried out within, and supported by, the collaborative research center SFB 1029 on “Substantial efficiency increase in gas turbines through direct use of coupled unsteady combustion and flow dynamics”, and funded by the German Research Foundation (DFG). It highlights theoretical and practical aspects, and corresponding solutions, that are important for the development of future energy conversion systems, thus offering a timely guide for researchers and practitioners in the field of aeronautics, turbomachinery, control and combustion.  Preface Contents Part I: Constant Volume Combustion and Combustion Control Pressure Gain and Specific Impulse Measurements in a Constant-Volume Combustor Coupled to an Exhaust Plenum 1 Introduction 2 Experimental Setup and Diagnostics 3 Results and Discussion 3.1 Effect of a Nozzled Plenum on the Unsteady Combustor Dynamics 3.2 Effect of the Main Operating Parameters on the Time-Averaged Combustor Performance 4 Conclusion References Control of Auto-ignitive Wave Propagation Modes from Hot Spots by Mixture Tailoring in Shockless Explosion Combustion 1 Introduction 2 Experimental and Numerical Methods 3 Extension of Excitation Time by Dilution 3.1 Influence of Dilution on Excitation Time and Temperature Sensitivity of Ignition Delay Time 3.2 Influence of Dilution on the Non-dimensional Regime Parameters 4 Decreasing the Temperature Sensitivity of Ignition Delay Time by Fuel Blending 4.1 Effect of Fuel Blending on Temperature Sensitivities of Ignition Delay Times 4.2 Influence of Fuel Tailoring on Non-dimensional Regime Parameters 5 Conclusions References Autoignition Modes in a Shockless Explosion Combustor 1 Introduction 2 Experimental Setup and Measurement Procedure 2.1 k-means Clustering 2.2 Fuel Injection Modelling 3 Results 3.1 Clustering the Pressure Signals 3.2 Clustering the Fuel Concentration Profiles 4 Conclusion References Fuel-Rich Natural Gas Conversion in HCCI Engines with Ozone and Dimethyl Ether as Ignition Promoters: A Kinetic and Exergetic Analysis 1 Introduction 2 Methodology 3 Results and Discussion 4 Conclusions References Enhancement of Blowout Limits in Lifted Swirled Flames in Methane-Air Combustor by the Use of Sinusoidally Driven Plasma Discharges 1 Introduction 2 Experimental Setup 2.1 Burner Geometry and Plasma Actuator Device 2.2 Electrical Characterization 3 Results and Discussions 3.1 Electrical Characterization 3.2 Flow Visualization and PIV Lab in Quiescent Mode 3.3 Extension of Lean Blow Out (LBO) Limits 4 Conclusions References Part II: Combustor- Turbine-Integration: Pressure Fluctuations and Turbulence Computational Simulation of an Exhaust Plenum Charged by a Multi-tube Pulsed Detonation Combustor 1 Introduction 2 Computational Setup 2.1 Extensions of the AMReX CFD Framework 2.2 One-Dimensional Model of the PDC Tube 3 Validation Based on Single-Tube–Single-Shot Tests 4 Multi-tube Firing with Partially Blocked Plenum Exit 4.1 Plenum Pressure for Forced Inert Gas Flow 4.2 Mean Plenum Pressure and End-to-End Total Pressure Differences 5 Conclusions References Pressure Fluctuations in an Annular Plenum Downstream of a Multi-tube Pulse Detonation Combustor 1 Introduction 2 Experimental Setup and Measurement Procedure 3 Results and Discussion 3.1 Examination of Pressure Signals 3.2 Longitudinal Change of Pressure Amplitudes 4 Conclusion References Reduction of Pressure Fluctuations in an Annular Pulsed Detonation Combustor Mockup by Iterative Learning Control Using Eigenvector-Based Binary Solution Sets and Iterative Model Identification 1 Introduction 2 Experimental Setup 2.1 Extension to a Nonlinear System 3 Binary Iterative Learning Control 3.1 Eigenvector-Based Reduction of Solution Space 4 ILC Based on Iterative Model Identification 4.1 Iterative Model Identification 4.2 Iterative Control Calculation Using the Deviation Model 5 Results 5.1 ILC Using Eigenvector-Based Binary Solution Sets 5.2 ILC Using Iterative Model Identification 6 Conclusion and Outlook References Part III: Combustor- Turbine-Integration: Cooling and Unsteady Performance Dynamic Forced Impingement Cooling: Latest Experimental Results Regarding Variations in Flow Guidance and Pulse Parameters 1 Introduction 2 Experimental Setup 3 Experimental Results 4 Summary and Conclusions References Time-Resolved Analysis of Film Cooling Effects Under Pulsating Inflow Conditions 1 Introduction 2 Experimental Facility 3 Methods 4 Results 5 Conclusion References Rotating Detonation Combustor Downstream Transition Passage Design Considerations 1 Introduction 2 Methodology 2.1 Solver Description 2.2 Investigated Passages Geometries 3 Aerothermal Characterization 3.1 Aerothermal Characterization Within the Transition Passage 3.2 Spatio-Temporal Evolution at the Outlet of the Passage 3.3 Impact of the Back Pressure on Pressure Gain 3.4 Pressure Loss Across the Transition Passage 4 Assessment of the Chemistry Effects Across the Passage 4.1 Passage Inlet Profile Defined by the Combustor 4.2 Simulation of the Supersonic Passage Without Chemistry 4.3 Simulation of the Isolated Diffusing Passage Without Chemistry 5 Conclusion References Part IV: Numerical Methods Linear Forcing of Compressible Isotropic Turbulence in Rectangular Domains with Adapted Locally Refined Grids 1 Motivation and Introduction 2 Basis Equations and Numerical Details 2.1 Governing Equations 2.2 Linear Forcing 2.3 Compressible Turbulence 2.4 Technical Details 3 Test Cases 3.1 Linear Forcing in Cubic Domains 3.2 Linear Forcing in Rectangular Domains 3.3 Linear Forcing with Box-Filtered Velocity in Rectangular Domains 4 Results 5 Conclusions References Modal Decomposition of Flow Data via Gradient-Based Transport Optimization 1 Introduction 2 Preliminaries and Problem Formulation 3 Main Results 4 Discretization 5 Numerical Examples 5.1 Viscous Burgers' Equation 5.2 Nonlinear Schrödinger Equation 5.3 FitzHugh–Nagumo Wave Train 6 Summary References Towards Data-Driven Model Reduction of the Navier-Stokes Equations Using the Loewner Framework 1 Introduction 2 Loewner Framework for the Navier-Stokes Equations 2.1 Navier-Stokes System 2.2 Transformation into Quadratic ODE System 2.3 Expansion of Quadratic ODE System into a Linear System 2.4 Transfer Function Interpolation for Quadratic ODE Systems 2.5 The Loewner Framework for Quadratic ODE Systems 2.6 Computational Details 3 Numerical Example 4 Conclusions and Future Work References Part V: Active Flow Control and Performance of Turbomachinery The Effect of Periodic Disturbance Patterns on the Efficiency of Active Flow Control in a Linear Stator Cascade 1 Introduction 2 -Patterns 3 Experimental Setup 3.1 Linear Stator Cascade 3.2 Disturbance Generator 3.3 Active Flow Control Setup 3.4 Local Blockage at the Test Rig 4 Disturbed Base Flow Measurements 5 Active Flow Control 5.1 Steady Blowing 5.2 Closed-Loop Control 5.3 Open vs. Closed Loop: Disturbance Rejection 5.4 Open vs. Closed Loop: Performance 6 Conclusion References DBD Plasma Actuation on the Blades of Axial-Flow Turbomachinery 1 Introduction 2 Experimental Facility 3 Discussion of Results 3.1 Relevant Definitions 3.2 Effect of Modulation Frequency 3.3 Overall Turbine Performance 4 Conclusions and Future Research References Numerical Analysis of Unsteady Compressor Performance Under Boundary Conditions Caused by Pulsed Detonation Combustion 1 Introduction 2 Method and Compressor Model 3 Validation 3.1 Steady-State Conditions 3.2 Unsteady Conditions 4 Calculation of Boundary Condition 5 Compressor Simulation Results 5.1 Unsteady Damping 5.2 Isentropic Efficiency 6 Conclusion References Efficiency Increase and Start-Up Strategy of an Axial Turbine Stage Under Periodic Inflow Conditions Using Extremum Seeking Control 1 Introduction 2 Experimental Setup 2.1 Characterization of the Turbine Behavior 3 Extremum Seeking Control 4 Applications Using ESC 4.1 Maximization of Efficiency and Specific Work 4.2 Start-Up Strategy of a PDC-Based Gas Turbine 5 Results 5.1 Efficiency and Specific Work Increase 5.2 Start-Up Process 6 Conclusion References Part VI: Active Flow Control Methods Experimental Investigations of Active Flow Control Using a Piezo Adaptive Blade in a Compressor Cascade Under Periodic Boundary Conditions with High Strouhal-Number 1 Introduction 2 Theoretical Considerations 3 Experimental Setup 3.1 The Piezo-Adaptive Compressor Stator Vane 4 Measurement Methods 5 Results 6 Conclusion References A Comparison of Optimal, Binary Closed-Loop Active Flow Control Applied to an Annular Compressor Stator Cascade with Periodic Disturbances 1 Introduction 2 Experimental Setup 2.1 Instrumentation and Data Acquisition 3 Closed-Loop Control 3.1 Model Identification 3.2 Controller Formulation 3.3 State Estimation 4 Results 4.1 Actuation Slot Experiments 4.2 Closed-Loop Experiments 5 Conclusion References Numerical Methodologies for Magnetohydrodynamic Flow Control for Hypersonic Vehicles 1 Introduction 2 Governing Equations 2.1 Resistive MHD System Equations 2.2 Plasma19 Equation of State 3 Numerical Methods 4 Validation 4.1 MHD System Validation Under Ideal Gas Law 4.2 Hypersonic Double Cone Tests 5 Results 5.1 Hypersonic Double Cone with Electrodynamic Effect 6 Conclusions References Author Index