MEASUREMENT OF COMBUSTION RADICALS USING VISIBLE/NEAR INFRARED DIODE LASERS

TO ACHIEVE A DETAILED AND QUANTITATIVE UNDERSTANDING OF COMBUSTION CHEMISTRY, NEW DIAGNOSTIC METHODS THAT CAN QUANTIFY THE IMPORTANT REACTIVE SPECIES PRESENT IN A COMBUSTION SYSTEM ARE REQUIRED. MOST EXISTING LASER-BASED TECHNIQUES ARE UNABLE TO PROVIDE ABSOLUTE SPECIES NUMBER DENSITIES AND USUALLY REQUIRE VERY HIGH COST LASERS. THIS PROJECT STUDIES A NEW LASER-BASED COMBUSTION DIAGNOSTIC THATCOMBINES TWO RECENT TECHNOLOGICAL ADVANCES-THE USE OF INEXPENSIVE VISIBLE OR NEAR-INFRARED DIODE LASERS AND HIGH FREQUENCY WAVELENGTH MODULATION SPECTROSCOPY-TO ACHIEVE QUANTITATIVE, HIGHLY SENSITIVE, AND RAPID TIME RESPONSE DETECTION OF COMBUSTION REACTION INTERMEDIATES. PHASE I EXPERIMENTS FOCUS ON MEASURING THE KEY SPECTRAL PARAMETERS OF A REPRESENTATIVE SPECIES, THE FORMYL RADICAL (HCO), AND DETERMINING THE DETECTION LIMITS FOR THE RADICAL IN A COMBUSTION ENVIRONMENT. THE RESULTS WILL PROVIDE THE BASIS FOR DEVELOPING A PROTOTYPE INSTRUMENT FOR IN-SITU COMBUSTIONSTUDIES IN PHASE II.