In this chapter, several of the diagnostic techniques commonly used to investigate combustion phe... more In this chapter, several of the diagnostic techniques commonly used to investigate combustion phenomena are reviewed, and a brief survey is provided of the mechanical probing techniques used to measure temperature, flow velocity, pressure and species concentrations (including flue gas diagnostics). The chapter includes an overview of optical techniques used for flow diagnostics, species concentration and temperature measurements in reacting flows. The use of imaging and multidimensional diagnostics for typical structures in the combustion field is also outlined. The simultaneous use of different planar measurement techniques describes state-of-the-art of laser diagnostics in combustion research, and the potential for laser-diagnostics to validate these approaches, as used in numerical simulations. Keywords: Combustion diagnostics; local and spatial resolution; invasive and non-invasive techniques; visualization techniques; absorption and emission spectroscopy; laser-induced fluorescence and phosphorescence; Mie scattering; Rayleigh scattering; linear and nonlinear Raman scattering; laser-induced incandescence; multidimensional and multiparameter laser diagnostics
In this study, the occurrence of auto-ignition centers in a two-stroke SI engine was investigated... more In this study, the occurrence of auto-ignition centers in a two-stroke SI engine was investigated using planar laserinduced fluorescence (PLIF). An experimental SI engine equipped with glass windows to enable full optical access into the combustion chamber was operated under knocking conditions. The pulsed output of two XeCl excimer lasers was formed into planar light sheets (300 μm × 4 cm), which were spatially overlapped and directed into the combustion chamber of the operating engine. Unburned fuel components fluoresce strongly when illuminated with XeCl laser radiation; burned regions display no fluorescence. Self-ignited regions therefore show up as dark sites in the fluorescence images, indicating local consumption of the fuel. The resulting PLIF images were recorded using fast-gated ICCD cameras. By delaying the second laser pulse a specific time (100 ns—600 μs), image pairs were acquired which allowed the temporal development and mutual influence of hot-spots to be studied. The short laser pulse duration (20 ns), the two-dimensional nature of the imaged region and the strong signals obtained from our detection scheme yield very detailed information of the self-ignited regions. Approximately 20 000 image pairs were recorded. As important quantities, spatial distribution and expansion velocities were extracted from the PLIF images and investigated statistically.
Page 1. 1 982468 Two-Dimensional Temperature Measurements in an SI Engine Using Two-Line Tracer L... more Page 1. 1 982468 Two-Dimensional Temperature Measurements in an SI Engine Using Two-Line Tracer LIF Svenja Einecke and Christof Schulz PCI, Universität Heidelberg Volker Sick MEAM, University of Michigan Andreas ...
In this chapter, several of the diagnostic techniques commonly used to investigate combustion phe... more In this chapter, several of the diagnostic techniques commonly used to investigate combustion phenomena are reviewed, and a brief survey is provided of the mechanical probing techniques used to measure temperature, flow velocity, pressure and species concentrations (including flue gas diagnostics). The chapter includes an overview of optical techniques used for flow diagnostics, species concentration and temperature measurements in reacting flows. The use of imaging and multidimensional diagnostics for typical structures in the combustion field is also outlined. The simultaneous use of different planar measurement techniques describes state-of-the-art of laser diagnostics in combustion research, and the potential for laser-diagnostics to validate these approaches, as used in numerical simulations. Keywords: Combustion diagnostics; local and spatial resolution; invasive and non-invasive techniques; visualization techniques; absorption and emission spectroscopy; laser-induced fluorescence and phosphorescence; Mie scattering; Rayleigh scattering; linear and nonlinear Raman scattering; laser-induced incandescence; multidimensional and multiparameter laser diagnostics
In this study, the occurrence of auto-ignition centers in a two-stroke SI engine was investigated... more In this study, the occurrence of auto-ignition centers in a two-stroke SI engine was investigated using planar laserinduced fluorescence (PLIF). An experimental SI engine equipped with glass windows to enable full optical access into the combustion chamber was operated under knocking conditions. The pulsed output of two XeCl excimer lasers was formed into planar light sheets (300 μm × 4 cm), which were spatially overlapped and directed into the combustion chamber of the operating engine. Unburned fuel components fluoresce strongly when illuminated with XeCl laser radiation; burned regions display no fluorescence. Self-ignited regions therefore show up as dark sites in the fluorescence images, indicating local consumption of the fuel. The resulting PLIF images were recorded using fast-gated ICCD cameras. By delaying the second laser pulse a specific time (100 ns—600 μs), image pairs were acquired which allowed the temporal development and mutual influence of hot-spots to be studied. The short laser pulse duration (20 ns), the two-dimensional nature of the imaged region and the strong signals obtained from our detection scheme yield very detailed information of the self-ignited regions. Approximately 20 000 image pairs were recorded. As important quantities, spatial distribution and expansion velocities were extracted from the PLIF images and investigated statistically.
Page 1. 1 982468 Two-Dimensional Temperature Measurements in an SI Engine Using Two-Line Tracer L... more Page 1. 1 982468 Two-Dimensional Temperature Measurements in an SI Engine Using Two-Line Tracer LIF Svenja Einecke and Christof Schulz PCI, Universität Heidelberg Volker Sick MEAM, University of Michigan Andreas ...
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