Fluorescence Imaging of Underexpanded Jets and Comparison with CFD

摘要: *† ‡ § An experimental study of underexpanded and highly axisymmetric nitrogen free jets seeded with 0.5% nitric oxide (NO) issuing from a sonic orifice was conducted at NASA Langley Research Center. Reynolds numbers based on nozzle exit conditions ranged 770 to 35,700, exit-to-ambient jet pressure ratios 2 35. These flows were non-intrusively visualized spatial resolution approximately 0.14 mm x 1 thick temporal 1µs using planar laser-induced fluorescence (PLIF) NO, the laser tuned stronglyfluorescing UV absorption bands Q1 band head near 226.256 nm. Three laminar cases selected for comparison computational fluid dynamics (CFD). The run GASP (General Aerodynamic Simulation Program) Version 4. Comparisons fundamental wavelength flow showed good agreement between CFD experiment all three test cases, while comparisons Mach disk location diameter lower ratios, tendency slightly underpredict these parameters increasing ratio.