Laser Diagnostics and Optical Measurement Techniques

Transcription

1 Laser Diagnostics and Optical Measurement Techniques in Internal Combustion Engines by Hua Zhao

2 Preface... xi Chapter 1. Optical Engines Introduction Optical Access Optical Access Through the Cylinder Head Optical Access Through the Piston Optical Access Through the Sides Endoscopic Access Optical Materials Operation of Optical Engines...9 References...10 Chapter 2. Introduction to Laser-Based Optical Instruments Overview of Laser-Based Optical Instruments Lasers High-Energy Pulsed Lasers High-Repetition Pulsed Lasers Continuous Wave Lasers Laser Beam Delivery and Focusing Gaussian Laser Beam Focusing of a Gaussian Laser Beam Laser Sheet Optics Optics and Photodetection Systems Optics Photon Detectors and Charge-Coupled Device (CCD) Cameras High-Speed Imaging Image Processing and Calibration Summary...39 References...40 Further Reading...40 Websites...40 v

3 Chapter 3. Fundamentals of Laser Spectroscopic Techniques Introduction Fundamentals of Molecular Spectroscopy Internal Energy of a Molecule Population of Energy Levels Raman and Rayleigh Scattering Rayleigh Scattering and Its Measurement Raman Scattering Spectrum Measurement of Raman Scattering Laser-Induced Fluorescence Comparison of LRS, SRS, and LIF Summary...69 References...70 Further Reading...70 Chapter 4. Principle and Application of LDA and PIV for In-Cylinder Flow Measurements Introduction Laser Doppler Anemometry The Principle of Laser Doppler Anemometry Laser and Transmitting Optics Light Collection System Signal Processing Discrimination of Flow Direction by Frequency Shifting Seeding and Particles Accuracy Advanced LDA Systems Data Analysis of In-Cylinder Flows Applications of LDA to IC Engines Particle Image Velocimetry (PIV) Principle of Particle Image Velocimetry Operation of the Digital PIV System Lasers and Light Sheets Imaging Optics and Perspective Errors Evaluation of Particle Image Displacement Vectors Seeding Particles Optimization of a PIV System Postprocessing of PIV Data Advanced PIV Systems PIV Measurements in IC Engines vi

4 4.4 Summary References Chapter 5. In-Cylinder Fuel and Combustion Specie Measurement by Laser- Induced Fluorescence Introduction Fuel Vapor Concentration Measurement by PLIF Principle of Operation Selection of Fluorescence Tracers Experimental Setup of PLIF Calibration of PLIF Images In-Cylinder Fuel Distribution Measurements by PLIF Visualization of Combustion Species by PLIF Introduction Experimental Considerations PLIF Measurements of OH PLIF Measurements of NO Visualization of Formaldehyde by PLIF Imaging of Water Vapor and CO by the Two-Photon LIF Technique Summary References Chapter 6. Fuel and Mixture Composition Measurement by Raman and Rayleigh Scattering Techniques Introduction Fuel Concentration Measurement by Laser Rayleigh Scattering Principle of Operation Implementation of LRS Minimization of Background Light in LRS Filtered Rayleigh Scattering Application of LRS to IC Engines Measurement of Mixture Composition by Spontaneous Raman Scattering Introduction Principle of Operation Experimental Setup of SRS Background Radiation and Signal-to-Noise Ratio Data Analysis and Calibration Applications of the SRS Scattering Technique to IC Engines vii

5 6.3.7 Multispecies Measurements by SRS in a CAI Combustion Engine Summary References Chapter 7. Fuel Injection and Spray Characterization Introduction Direct Imaging of Spray and Droplets Liquid Droplet Sizing by the Fraunhofer Diffraction Method Fraunhofer Diffraction Implementation of the Fraunhofer Diffraction Method Droplet Sizing and Velocity Measurements by the Phase Doppler Particle Analyzer (PDPA) The Principle of the PDPA Implementation of the PDPA Data Reduction and Presentation Optimization of a PDPA System Application of PDPA to IC Engines Two-Dimensional Visualization of Spray Atomization by Mie Scattering and Laser-Induced Fluorescence (LIF) Two-Dimensional Spray Imaging Through Mie Scattering or PLIF Laser Sheet Droplet Sizing (LSD) by Combined Mie Scattering and LIF Simultaneous Visualization of Fuel Vapor and Liquid Fuel by the Laser-Induced Exciplex Fluorescence Technique Principle of Laser-Induced Exciplex Flourescence Technique Experimental Setup of LIEF Quantitative Analysis of Fuel Vapor Concentration Using PLIEF Application of PLIEF for In-Cylinder Fuel Visualization Application of LIEF to In-Cylinder Diesel Spray Measurement Summary References Chapter 8. Combustion Spectroscopy and Visualization Techniques Introduction Combustion Spectroscopy Light Emission of Combustion viii

6 8.2.2 Light Absorption of Combustion Species Detection of Emission and Absorption Application of Light Emission and Absorption Techniques Chemiluminescence Imaging Schlieren and Shadowgraph Techniques for Nonluminous Flow and Combustion Visualization Summary References Chapter 9. Gas Temperature Measurement Introduction Radiation Thermometry Principles of Radiation Thermometry Implementation of Radiation Thermometry Laser Rayleigh Scattering (LRS) Thermometry Principle of Laser Rayleigh Thermometry Implementation and Application of Rayleigh Thermometry Temperature Measurement by Spontaneous Raman Scattering (SRS) Principle of Raman Thermometry Implementation and Application of Raman Thermometry Temperature Measurement by Coherent Anti-Stokes Raman Scattering (CARS) Principle of CARS Thermometry Implementation of CARS Nitrogen Thermometry CARS Measurements in IC Engines Two-Dimensional Temperature Measurement by PLIF Introduction to Fluorescence Thermometry Monochromatic Fluorescence Thermometry Two-Line Fluorescence Thermometry Summary References Chapter 10. In-Cylinder Soot Concentration and Particle Size Measurement Introduction The Two-Color Method Principle of the Two-Color Method ix

7 Implementation of the Two-Color Method Accuracy Full-Field Two-Color Measurement Soot Concentration Measurement by the Light-Extinction Method Principle of the Light-Extinction Method Implementation of the Light-Extinction Method Laser-Induced Incandescence Introduction Soot Volume Fraction Measurement by LII Soot Particle Sizing Using LII and Laser Scattering (LS) Particle Sizing by Time-Resolved LII (TiRe-LII) Further Considerations of LII Techniques References Index About the Author x