Resonant Holographic Interferometry, An Innovative Technique For Combustion Diagnostics

This synopsis discusses our development efforts in the area of resonant holographic interferometry (RHI). RHI is a completely nonintrusive optical diagnostic suitable for a wide range of gas dynamic investigations. As described in previous reports, RHI is a hybrid technique that combines the multi-dimensional imaging capability of holography, the phase sensitive detection of interferometry, and the species specificity of spectroscopy. When combined with tomography, RHI provides three-dimensional characterization and quantitative measurement of species concentrations, temperature, velocity, pressure, mixing and other thermophysical quantities. Specific Aims The specific aims of this program have not been modified from the original goals. These goals are to theoretically and experimentally demonstrate RHI by quantitatively measuring chemical species of interest to the Army in controlled combustion environments. Efforts this past year were focused on making quantitative RHI concentration measurements in a calibrated laboratory burner. Results During this reporting period RHI measurements of hydroxyl radicals (OH) were recorded in a WolfhartParker (W-P) slot burner. The data is currently being analyzed and compared to absorption data and predictions based on our RHI model. The method of Phase Shifting Interferometry (PSI) was developed and implemented for converting an unwrapped phase map into concentration data. The PSI method was adapted for automation using a personal computer. A two-reference beam RHI system previously developed under this research program was modified to accommodate a calibrated W-P slot burner. Phase Shift Interferometry (PSI) data reduction was facilitated by using a Correcting Holographic Optical Element (CHOE) as described in previous reports and an automated computer data reduction package. RHI data at several burner flow rates were recorded using the RHI holocamera. The burner was calibrated using thermocouples and absorption measurements. 14. SUBJECT TERMS