Simultaneous imaging of two-phase velocities in particle-laden flows by two-color optical phase discrimination

Journal Article · Thu Aug 05 00:00:00 EDT 2021 · Optics Letters

DOI:https://doi.org/10.1364/OL.428357· OSTI ID:1811949

Bi, Xiaopeng; Sun, Zhiwei; Lau, Timothy; Alwahabi, Zeyad; Nathan, Graham

In this Letter, we present a particle image/tracking velocimetry (PIV/PTV) technique for simultaneous velocity measurement of both fluid and particle phases, adopting newly developed optical phase discrimination methods and novel optical particles. Spherical acrylic (PMMA) particles of diameter $\sim \; <\#comment/>\mathrm{O}\left(100\text{µ <\#comment/>}\mathrm{m}\right)$ were used as the particle phase, while fine $\mathrm{B}\mathrm{A}\mathrm{M}:{\mathrm{E}\mathrm{u}}^{2+}$ phosphors of diameter $\sim \; <\#comment/>\mathrm{O}\left(1\text{µ <\#comment/>}\mathrm{m}\right)$ were used as the fluid tracer. Under Nd:YAG 355 nm laser excitation, both the laser-induced fluorescence (LIF) from PMMA and laser-induced phosphorescence (LIP) from $\mathrm{B}\mathrm{A}\mathrm{M}:{\mathrm{E}\mathrm{u}}^{2+}$ provided sufficiently strong signals for PIV imaging with two non-intensified cameras and were clearly separable for phase discrimination using spectral filters and temporal profiles. The advantages of the PIV/PTV method include the relatively low cost of $\mathrm{B}\mathrm{A}\mathrm{M}:{\mathrm{E}\mathrm{u}}^{2+}$ phosphors, high sphericity and narrow size distribution of PMMA particles with LIF emission, and direct optical discrimination eliminating artifacts, while requiring much less computational capacity for PIV/PTV processing of complex particle-laden flows.

• Sponsoring Organization: USDOE
• OSTI ID: 1811949
• Journal Information: Optics Letters, Journal Name: Optics Letters Journal Issue: 16 Vol. 46; ISSN 0146-9592; ISSN OPLEDP
• Publisher: Optical Society of America
• Country of Publication: United States
• Language: English