Simultaneous three-dimensional velocimetry and thermometry in gaseous flows using the stereoscopic vibrationally excited nitric oxide monitoring technique

Abstract

We present a demonstration of the simultaneous measurement of spatially resolved three-component velocity and temperature in gaseous flow fields using a variant of the vibrationally excited nitric oxide monitoring (VENOM) technique, based on planar laser induced fluorescence and molecular tagging velocimetry methods. Three-component velocity determinations were derived from two-dimensional molecular tagging velocity measurements employing sequential fluorescence image pairs obtained simultaneously by two cameras in stereoscopic configuration. Probing two different rotational states of nitric oxide (X²∏, υ^''=1), produced via fluorescence and collisional quenching from initial excitation to the A Σ⁺2 state, for the sequential velocimetry images allows simultaneous determination of the temperature field. Experimental measurements of velocity and temperature across an oblique shock result in mean values within 21 m/s for the three components of velocity and 20 K for planar temperature when compared to oblique shock calculations.

A Review of Femtosecond Laser-Induced Emission Techniques for Combustion and Flow Field Diagnostics

“…MTV techniques can be categorized by whether the atomic/molecular tracer is "seeded" or "unseeded". In "seeded" MTV methods, the flow is seeded with molecules (or atoms) such as ketone [119,120], ester [121], nitric oxide [122,123], and metal atoms [124,125]. Different atomic/molecular tracers are seeded in terms of different flow fields.…”

Femtosecond laser-induced cyano chemiluminescence in methane-seeded nitrogen gas flows for near-wall velocimetry

“…Velocity field mapping of gas flows is an essential task in fluid science, where non-intrusive optical methods play an important role. In the last few decades, many optical velocimetric techniques have been developed, among which the representative ones include laser Doppler velocimetry (LDV) [1], particle image velocimetry (PIV) [2], and molecular tagging velocimetry (MTV) [3][4][5][6]. Velocimetric techniques based on Doppler effect work better in high-speed flow field, and as a particle-seeding technique PIV suffers from problems such as particle lag and device contamination.…”