Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Femtosecond laser activation and sensing of hydroxyl for velocimetry in reacting flows

Not Accessible

Your library or personal account may give you access

Abstract

A molecular tagging method for velocity measurements in reacting environments such as propulsion devices and high-temperature combustion-assisted wind tunnels is described. The method employs a femtosecond (write) laser to photodissociate ${{\rm{H}}_2}{\rm{O}}$, a common combustion product, into a locally high concentration of OH radicals. These radicals are tracked by planar laser-induced fluorescence (PLIF) from the ${{\rm{A}}^2}\Sigma - {{\rm{X}}^2}\Pi$ (1–0) vibrational band excited by a time-delayed 284 nm (read) laser sheet. As a variant of hydroxyl tagging velocimetry, the source laser can also be used to dissociate nitrogen for femtosecond laser electronic excitation tagging velocimetry to mark the time-zero location of the write laser for velocimetry in non-reacting regions using the same imaging system without OH PLIF. The OH tracer lifetime is studied in a hydrogen-air Hencken burner operating at $\Phi = 0.5 - 1.8$ to evaluate the tracking capability for velocimetry over a range of conditions. Effects of changing read laser wavelength, excitation energy, and influence of background flame emission are also studied. The data processing methodology and results are described for tracking displacements with 9–25 µm uncertainty in a hydrogen diffusion flame. This method presents several advantages in operational convenience and availability of laser sources, and it provides an avenue for improvements in the repetition rate, precision, and applicability over previously demonstrated hydroxyl tagging schemes.

© 2020 Optical Society of America

Full Article  |  PDF Article
More Like This
Vibrationally excited hydroxyl tagging velocimetry

Nathan Grady and Robert W. Pitz
Appl. Opt. 53(31) 7182-7188 (2014)

Flame flow tagging velocimetry with 193-nm H2O photodissociation

Joseph A. Wehrmeyer, Lubomir A. Ribarov, Douglas A. Oguss, and Robert W. Pitz
Appl. Opt. 38(33) 6912-6917 (1999)

Hydroxyl tagging velocimetry method optimization: signal intensity and spectroscopy

Lubomir A. Ribarov, Shengteng Hu, Joseph A. Wehrmeyer, and Robert W. Pitz
Appl. Opt. 44(31) 6616-6626 (2005)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (12)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Tables (1)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved