Final Report Summary - DALDECS (Development and Application of Laser Diagnostic Techniques for Combustion Studies)
The scientific outcomes of the sub-tasks of the project are summarized below.
Detection of new species. The non-linear optical techniques polarization spectroscopy (PS) and degenerate four-wave mixing (DWFM) have been developed for detection of species in the mid-infrared spectral range, for example hydrogen cyanide (HCN). A novel detector concept based on photon up-conversion has provided enhanced sensitivity for mid-infrared detection. Photo-fragmentation laser-induced fluorescence (PFLIF) has been developed for two-dimensional imaging of non-fluorescing species and successfully demonstrated for visualization of hydrogen peroxides.
Quantitative measurements. Fluorescence quenching rates, necessary for absolute concentration measurements by means of the widely employed laser-induced fluorescence (LIF) method, have been measured for carbon monoxide (CO) and the hydroxyl radical (OH). In addition the LIF technique has been developed for detection of ammonia (NH3), water vapor and oxygen as well as the cyanide (CN), amide (NH), amidogen (NH2) and formal (HCO) radicals.
Light detection and ranging (LIDAR) has been developed for combustion diagnostics under conditions with restricted optical access through a single port, typically in large-scale power plants or gas turbines. This near-field LIDAR concept has been successfully demonstrated for thermometry, soot measurements and detection of NH3 and potassium chloride (KCl).
Advanced imaging - high-speed visualization and multi-species detection. Temporally resolved imaging in three dimensions, i.e. 4D measurements, has been achieved and provides a significant enhancement of laser diagnostics for studies of turbulent combustion. Simultaneous visualization of multiple species using clusters of lasers has been employed in studies of turbulent combustion. In particular for investigation of a special combustion mode lacking a definite flame zone, the so-called Distributed Reaction Zone regime, resulting in completely new information.
Advanced imaging - Structured Laser Illumination Planar Imaging (SLIPI). Interpreting optical signals transmitted through fuel sprays in liquid-fed combustion represents a challenge for their characterization. The developed SLIPI concept for sample illumination and signal analysis provides significant image contrast enhancement making accurate quantitative characterization of fuel sprays in terms of droplet size and distributions feasible.
The project objectives have been fulfilled to a great extent. The research has resulted in state-of-the-art laser-based techniques for combustion diagnostics. In particular the development of 4D-imaging and imaging of liquid sprays, but also of LIDAR remote sensing and detection of additional combustion-relevant species.
The developed techniques have been employed for combustion research. For example, the SLIPI technique for diesel spray characterization, 4D and multiscalar imaging for studies of turbulent combustion, LIDAR for thermometry during room fire development, photo-fragmentation fluorescence for ignition studies in an engine and detection of nitrogen species to validate models of flame chemistry.
The research has attracted attention in the scientific community. Multiple publications on the project research were selected for oral presentations at the 34th and 35th International Symposiums on Combustion in 2012 (Warsaw, Poland) and 2014 (San Francisco, USA). The SLIPI concept has gained attention within the spray research community and a publication received the ICLASS2009 Tanasawa Award, at the 12th International Conference on Liquid Atomization and Spray Systems (ICLASS) 2012 (Heidelberg, Germany).
Knowledge gained from development and application of laser-diagnostic methods for combustion studies has successfully been transferred to the fields of plasma physics and catalysis, thus opening up for new research.
Detection of new species. The non-linear optical techniques polarization spectroscopy (PS) and degenerate four-wave mixing (DWFM) have been developed for detection of species in the mid-infrared spectral range, for example hydrogen cyanide (HCN). A novel detector concept based on photon up-conversion has provided enhanced sensitivity for mid-infrared detection. Photo-fragmentation laser-induced fluorescence (PFLIF) has been developed for two-dimensional imaging of non-fluorescing species and successfully demonstrated for visualization of hydrogen peroxides.
Quantitative measurements. Fluorescence quenching rates, necessary for absolute concentration measurements by means of the widely employed laser-induced fluorescence (LIF) method, have been measured for carbon monoxide (CO) and the hydroxyl radical (OH). In addition the LIF technique has been developed for detection of ammonia (NH3), water vapor and oxygen as well as the cyanide (CN), amide (NH), amidogen (NH2) and formal (HCO) radicals.
Light detection and ranging (LIDAR) has been developed for combustion diagnostics under conditions with restricted optical access through a single port, typically in large-scale power plants or gas turbines. This near-field LIDAR concept has been successfully demonstrated for thermometry, soot measurements and detection of NH3 and potassium chloride (KCl).
Advanced imaging - high-speed visualization and multi-species detection. Temporally resolved imaging in three dimensions, i.e. 4D measurements, has been achieved and provides a significant enhancement of laser diagnostics for studies of turbulent combustion. Simultaneous visualization of multiple species using clusters of lasers has been employed in studies of turbulent combustion. In particular for investigation of a special combustion mode lacking a definite flame zone, the so-called Distributed Reaction Zone regime, resulting in completely new information.
Advanced imaging - Structured Laser Illumination Planar Imaging (SLIPI). Interpreting optical signals transmitted through fuel sprays in liquid-fed combustion represents a challenge for their characterization. The developed SLIPI concept for sample illumination and signal analysis provides significant image contrast enhancement making accurate quantitative characterization of fuel sprays in terms of droplet size and distributions feasible.
The project objectives have been fulfilled to a great extent. The research has resulted in state-of-the-art laser-based techniques for combustion diagnostics. In particular the development of 4D-imaging and imaging of liquid sprays, but also of LIDAR remote sensing and detection of additional combustion-relevant species.
The developed techniques have been employed for combustion research. For example, the SLIPI technique for diesel spray characterization, 4D and multiscalar imaging for studies of turbulent combustion, LIDAR for thermometry during room fire development, photo-fragmentation fluorescence for ignition studies in an engine and detection of nitrogen species to validate models of flame chemistry.
The research has attracted attention in the scientific community. Multiple publications on the project research were selected for oral presentations at the 34th and 35th International Symposiums on Combustion in 2012 (Warsaw, Poland) and 2014 (San Francisco, USA). The SLIPI concept has gained attention within the spray research community and a publication received the ICLASS2009 Tanasawa Award, at the 12th International Conference on Liquid Atomization and Spray Systems (ICLASS) 2012 (Heidelberg, Germany).
Knowledge gained from development and application of laser-diagnostic methods for combustion studies has successfully been transferred to the fields of plasma physics and catalysis, thus opening up for new research.