Instantaneous dual-tracer PLIF measurements of molecular mixing in axisymmetric jets

G. F. King, R. P. Lucht, J. C. Dutton

Research output: Contribution to conferencePaper

Abstract

A dual-tracer PLIF technique for making instantaneous, quantitative measurements of molecularly mixed fluid fraction is presented and demonstrated in an axisymmetric jet in a mild co-flow. The two-camera, two-laser technique uses PLIF of nitric oxide (NO) seeded in a nitrogen jet to mark unmixed jet fluid fraction, while PLIF of acetone seeded into the low velocity air co-flow marks total co-flow fluid fraction. By combining data from these two simultaneous images, quantitative measurements of molecularly mixed jet fluid fraction can be made on a pixel-by-pixel basis, while the "resolution-free" nature of the technique allows simultaneous study of overall flowfield characteristics and large-structure behavior. By calculating the jet fluid mixing efficiency, regions of subresolution stirring can also be visualized. Instantaneous images and probability density functions, calculated at x/d, = 2 and 3.5, are presented for Rejet, = 1000, 10,000, and 50,000. For the fully turbulent (Rejet = 50,000) conditions, stirring at subresolution scales is detected primarily on the jet side of the mixing layer. This creates a hybrid PDF behavior (stationary on the jet side of the mixing layer, marching on the co-flow side) that is not shown by passive scalar methods at equivalent image resolution.

Original languageEnglish (US)
StatePublished - Jan 1 1997
Event35th Aerospace Sciences Meeting and Exhibit, 1997 - Reno, United States
Duration: Jan 6 1997Jan 9 1997

Other

Other35th Aerospace Sciences Meeting and Exhibit, 1997
CountryUnited States
CityReno
Period1/6/971/9/97

ASJC Scopus subject areas

  • Space and Planetary Science
  • Aerospace Engineering

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    King, G. F., Lucht, R. P., & Dutton, J. C. (1997). Instantaneous dual-tracer PLIF measurements of molecular mixing in axisymmetric jets. Paper presented at 35th Aerospace Sciences Meeting and Exhibit, 1997, Reno, United States.