NO PLIF Imaging in the CUBRC 48" Shock Tunnel

Abstract

Nitric Oxide Planar Laser-Induced Fluorescence (NO PLIF) imaging is demonstrated at a 10 kHz repetition rate in the Calspan-University at Buffalo Research Center's (CUBRC) 48-inch Mach 9 hypervelocity shock tunnel using a pulse burst laser-based high frame rate imaging system. Sequences of up to ten images are obtained internal to a supersonic combustor model, located within the shock tunnel, during a single ~10-millisecond duration run of the ground test facility. This represents over an order of magnitude improvement in data rate from previous PLIF-based diagnostic approaches. Comparison with a preliminary CFD simulation shows good overall qualitative agreement between the prediction of the mean NO density field and the observed PLIF image intensity, averaged over forty individual images obtained during several facility runs.

Review of ultra-high repetition rate laser diagnostics for fluid dynamic measurements

“…As an example, mixing of residual 355 nm pump with the signal output at ∼622 nm has been shown to produce ∼0.5 mJ/pulse at ∼226 nm. This has enabled NO PLIF imaging in a small laboratory wind tunnel, at framing rates as high as 250 kHz , in the NASA-Langley 31 Mach 10 wind tunnel, at framing rates as high as 1 MHz (Jiang et al 2011c), and in the Cornell-University of Buffalo Research Center (CUBRC) 48 shock tunnel, where a sequence of 10 NO PLIF flow visualization images was obtained at 10 kHz framing rate in a single facility 'shot' (Jiang et al 2011a). Figure 12 shows a pair, out of more than 200 obtained, of time-correlated NO PLIF 10-20 frame image sequences obtained from the boundary layer of a 20 • flat plate model, in which transition was induced using a variety of different shaped protuberances including cylinders, a triangle and the boundary layer transition-detailed test object, recently flown on the Space Shuttle.…”

NO PLIF Visualizations of the Orion Capsule in LENS-I

“…PLIF has previously been used by NASA researchers to visualize capsule RCS jets, 17 simulated heat shield ablation, 18 flow over flat plates and cavities, 19 and various other geometries. Additionally, a high-speed (~100 kHz -1 MHz) NO PLIF system has previously been used to study a non-reacting supersonic combustor cavity in Calspan University at Buffalo Research Center's (CUBRC) 48‖ shock tunnel, 20 but this is the first application of PLIF to study RCS jets in a large-scale pulsed hypersonic facility. The LENS-I facility allowed RCS jet flows to be studied while varying the flow enthalpy.…”