Measurement of Liquid Acetone Fluorescence and Phosphorescence for Two-Phase Imaging

Tran, Thao; Kochar, Yash; Seitzman, Jerry M.

doi:10.2514/6.2005-827

Cited by 14 publications

(12 citation statements)

References 14 publications

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“…The fluorescent seed was acetone, blended with each test fluid at a concentration of 5% by volume. 25,26 The laser-induced fluorescence technique allowed the determination of the distribution of the vapor concentration surrounding a droplet at each stage of droplet breakup in supersonic flow. Due to the very violent and rapid droplet disruption that occurs in supersonic flow, the acetone tracer was expected to provide a reasonable indication of the total amount and extent of the vaporized fluid.…”

Section: Imaging Systemsmentioning

confidence: 99%

Breakup and vaporization of droplets under locally supersonic conditions

Kim

Hermanson

2012

Physics of Fluids

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CH 3 CH 2 OD / D 2 O binary condensation in a supersonic Laval nozzle: Presence of small clusters inferred from a macroscopic energy balanceThe disruption and vaporization of simulated fuel droplets in an accelerating supersonic flow was examined experimentally in a draw-down supersonic wind tunnel. The droplets achieved supersonic velocities relative to the surrounding air to give relative Mach numbers of up to 1.8 and Weber numbers of up to 300. Mono-disperse, 100 μm-diameter fluid droplets were generated using a droplet-on-demand generator upstream of the tunnel entrance. Direct close-up single-and multiple-exposure imaging was used to examine the features of droplet breakup and to determine the droplet velocities. Laser-induced fluorescence (LIF) imaging of the disrupting droplets was performed using acetone fluorescence to determine the dispersion of the expelled vapor. Three test liquids were employed: 2-propanol and tetraethylene glycol dimethyl ether as non-volatile fluids and a 50/50 hexanol-pentane mixture (Hex-Pen 50/50). The vapor pressure of the Hex-Pen 50/50 was sufficiently high to cause the droplet fluid to potentially become superheated in the decreased static pressure of the supersonic stream. The dynamics for 2-propanol and Hex-Pen 50/50 droplets were similar up to the point of disruption, which occurred more rapidly for the more volatile Hex-Pen 50/50. A 1D dynamic droplet model was developed to provide a first estimate of the expected droplet acceleration and velocity. The actual droplet velocities were in reasonable agreement with the model up to the point at which significant droplet disruption and mass loss commenced. The droplet deformation and breakup patterns for these supersonic flow conditions can be classified into four different flow regions characterized by changes in the Weber number with downstream distance as the droplets accelerate, however, those flow regimes and Weber number ranges were different than those seen for droplets disrupting in shock tubes. The disruption patterns were seen to be generally similar for the different fluids, though droplet disruption occurred more rapidly for the more volatile fluid. LIF imaging established the extent of the dispersion of the expelled vapor. Examination of the vapor clouds surrounding the droplets suggests that Hex-Pen 50/50 droplets had a greater rate of vaporization than 2-propanol droplets starting at approximately 2 mm downstream of the nozzle throat, where the air static pressure became lower than the liquid vapor pressure. This suggests that droplet superheating can have an effect on the extent and rate of droplet vaporization under locally supersonic conditions. The degree of vaporization for Hex-Pen 50/50 was approximately 1.3 times greater than that of the non-volatile fluids over all downstream distances in the supersonic flow. C 2012 American Institute of Physics. [http://dx.

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Section: Imaging Systemsmentioning

confidence: 99%

Breakup and vaporization of droplets under locally supersonic conditions

Kim

Hermanson

2012

Physics of Fluids

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“…Other quantitative measurements of acetone vapour concentration in presence of droplets were reported by Ritchie and Seitzman (2001): a model was developed to use PLIF signal to derive droplet size as well by taking into account the disturbing effect of the droplets. Tran et al (2005) studied particularly the fluorescence and phosphorescence of liquid acetone to assist in the development of quantitative mixing measurements in two-phase flows.…”

Section: List Of Symbolsmentioning

confidence: 99%

Composition measurement of bicomponent droplets using laser-induced fluorescence of acetone

et al. 2007

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“…The L/R ratio increases at the saturation line near 90°C due to that the right flank from 440 nm and up growing weaker, making the emission spectrum approach that of hexafluoroacetone. 8 When comparing the emission spectrum to that of acetone using 266 nm data from Tran et al, 9 fluoroketone has an almost identical emission peak near 420 nm, and…”

Section: Resultsmentioning

confidence: 99%

“…When phosphorescence is of importance, i. e. in the absence of oxygen, the emission spectrum of acetone will be broadened and red-shifted. Extrapolating from the 266 and 285 nm excitation results of Tran et al, 9 using 355 nm rather than 266 nm excitation will lead to red-shift of the fluorescence signal and increased importance of the phosphorescence signal. While no data on acetone emission for 355 nm excitation was found in literature by the present author, the emission spectrum given for 308 nm excitation by Lozano et al 7 is substantially red-shifted, exhibiting double peaks at 445 and 480 nm and having a FWHM of 153 nm.…”

Section: Fluoroketonementioning

confidence: 95%

Characterization of a Perfluorinated Ketone for LIF Applications

Gustavsson

Segal

2008

46th AIAA Aerospace Sciences Meeting and Exhibit

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A perfluorinated ketone, 2-trifluoromethyl-1,1,1,2,4,4,5,5,5-nonafluoro-3-pentanone, has been investigated to determine several physical and spectroscopic properties. It was found to exhibit fluorescence similar to that of acetone, emitting over the 360-550 nm range with a peak near 420 nm when excited at 355 nm. This compound's emission is nearly unaffected over a wide range of temperature and pressure in an argon bath gas. Its fluorescence efficiency was found to be three times higher than that of acetone. Combined with low reactivity and thermal stability up to 500°C, this makes the material an excellent tracer for flow applications near critical conditions. NomenclatureP = pressure P c = critical pressure P R = reduced pressure, P/P c T = temperature T c = critical temperature T R = reduced pressure, T/T c V = molar volume λ = wavelength µ = dynamic viscosity ν = kinematic viscosity ρ = density I. IntroductionHE molecular structure of the perfluorinated ketone discussed in the present paper, 2-trifluoromethyl-1,1,1,2,4,4,5,5,5-nonafluoro-3-pentanone, also known as FK-5-1-12, and referred to as "fluoroketone" for brevity herein, is shown in Figure 1.This fluoroketone has several interesting features that make it an important material for research: ♦ High vapor pressure at ambient pressure -making the fluoroketone a good model for studies of the break-up and mixing of volatile fuels and enabling high seeding densities. ♦ Low critical pressure and temperature -facilitating the study of trans-and supercritical phenomena. ♦ Liquid fluoroketone low dynamic viscosity and high density -resulting in very low kinematic viscosity, making high-Re testing possible at modest flow speeds. ♦ Strong fluorescence with broadband excitation -making flow tracing using common high-power lasers, such as the 3rd and 4th order harmonics of a Nd:YAG laser, possible.

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Measurement of Liquid Acetone Fluorescence and Phosphorescence for Two-Phase Imaging

Cited by 14 publications

References 14 publications

Breakup and vaporization of droplets under locally supersonic conditions

Breakup and vaporization of droplets under locally supersonic conditions

Composition measurement of bicomponent droplets using laser-induced fluorescence of acetone

Characterization of a Perfluorinated Ketone for LIF Applications

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