scholarly journals Fluorescence Spectroscopy for Studying Evaporating Droplets Using the Dye Eosin-Y

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 5985
Author(s):  
Matthias Koegl ◽  
Christoph Weiß ◽  
Lars Zigan
Keyword(s):  
Mie Scattering ◽  
Droplet Evaporation ◽  
Experimental Investigations ◽  
Fluorescence Signal ◽  
Eosin Y ◽  
Droplet Deformation ◽  
Two Phase ◽  
Lif Spectroscopy ◽  
Single Droplets

Laser-induced fluorescence (LIF) spectroscopy using dyes is frequently applied for characterization of liquids and two-phase flows. The technique is utilized e.g., for mixing studies, thermometry, or droplet sizing. One major application of the LIF technique combined with Mie-scattering is the planar measurement of droplet sizes in spray systems. However, its uncertainty is determined, among others, by varying dye concentration and temperature changes occurring during mixing and droplet evaporation. Systematic experimental investigations are necessary to determine the influence of dye enrichment effects on the LIF-signal of single droplets. For these investigations, the fluorescence dye Eosin-Y is dissolved in water and ethanol, which are typical solvents and working fluids in bio-medical applications and power engineering. A photo-physical characterization of the mixtures under various conditions was conducted using a spectrometric LIF setup and a micro cell. For ethanol, a small temperature dependency of the Eosin-Y LIF signal is observed up to 373 K. Photo-dissociation of Eosin-Y is negligible for solution in ethanol while it is distinct in water. The LIF signals of the single droplets are studied with an acoustic levitator. Effects of droplet evaporation, droplet deformation and varying dye concentration on the LIF-signal are studied. The single droplet measurements revealed a complex change of the fluorescence signal with reduced droplet size. This is due to droplet deformations leading to variations in the internal illumination field as well as dye enrichment during evaporation.

scholarly journals Characterization of Nile Red as a Tracer for Laser-Induced Fluorescence Spectroscopy of Gasoline and Kerosene and Their Mixture with Biofuels

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2822 ◽  
Author(s):  
Matthias Koegl ◽  
Christopher Mull ◽  
Kevin Baderschneider ◽  
Jan Wislicenus ◽  
Stefan Will ◽  
...  
Keyword(s):  
Nile Red ◽  
Mie Scattering ◽  
Spectral Shift ◽  
Laser Induced Fluorescence ◽  
Fluorescence Signal ◽  
Spectral Absorption ◽  
Absorption And Emission ◽  
Ethanol Blends ◽  
Increasing Temperature

Suitable fluorescence tracers (“dyes”) are needed for the planar measurement of droplet sizes by using a combination of laser-induced fluorescence (LIF) and Mie scattering. Currently, no suitable tracers have been characterized for application in planar droplet sizing in gasoline and kerosene fuels, as well as biofuel blends. One promising tracer is nile red, which belongs to the fluorophore group. For its utilization for droplet size measurements, preliminary characterization of the fluorescence of the respective fuel tracer mixtures are mandatory. For this purpose, the fluorescence and absorption behavior of nile red dissolved in the surrogate fuels Toliso and Jet A-1 as well as in biofuel blends was investigated. The fluorescence signal for nile red that was dissolved in the two base fuels Toliso and Jet A-1 showed a linear behavior as a function of dye concentration. The temperature effect on spectral absorption and emission of nile red was investigated in a specially designed test cell. An ethanol admixture to Toliso led to a spectral shift towards higher wavelengths. The absorption and emission bands were shifted towards lower wavelengths with increasing temperature for all fuels. Both absorption and fluorescence decreased with increasing temperature for all fuels, except for E20, which showed an increased fluorescence signal with increasing temperature. Jet A-1 and its blends with hydroprocessed esters and fatty acids (HEFA) and farnesane did not exhibit explicit variations in spectral absorption or emission, but these blends showed a more distinct temperature dependence compared to the Toliso-ethanol-blends. The effect of photo-dissociation of the LIF signal of the fuel tracer mixtures was studied, and all fuel mixtures besides Toliso showed a more or less distinct decay in the fluorescence signal with time. In summary, all investigated fuel-tracer mixtures are suitable for LIF/Mie ratio droplet sizing in combination with nile red at moderate temperatures and low evaporation cooling rates.

A Theoretical and Experimental Study of the Characterization of Bubbles Using Light Scattering Interferometry

1991 ◽  
Vol 113 (3) ◽  
pp. 460-468 ◽  
Author(s):  
A. Bren˜a de la Rosa ◽  
S. V. Sankar ◽  
B. J. Weber ◽  
G. Wang ◽  
W. D. Bachalo
Keyword(s):  
Light Scattering ◽  
Surrounding Medium ◽  
Mie Scattering ◽  
Two Phase ◽  
General Validity ◽  
Doppler Method ◽  
Powerful Research Tool ◽  
Size And Morphology ◽  
Mie Scattering Theory

The present work details the theoretical and experimental research undertaken to determine the size and morphology of bubbles, and their dynamic characteristics such as velocity, number density, and volume flux using light scattering interferometry. The approach is based on the measurement of the phase difference of the interference fringe pattern which is produced when a particle passing through the probe volume defined by the intersection of two laser beams scatters light and interferes in the surrounding medium. Detailed analytical/numerical modeling of the phase Doppler approach using Mie scattering theory and the geometrical optics approximation resulted in optimum light scattering collection angles and calibration curves for bubble diagnostics. Using several techniques to generate a steady stream of monosize bubbles in the range from 6 μ to 1800 μm in diameter, the measurements obtained using the phase Doppler method were compared with direct photography yielding an agreement of better than 95 percent. The morphology of spheroidal bubbles was also investigated by placing the transmitting and receiving optical units at specified locations with respect to the scatterers. It is believed that this theoretical and experimental work has given the phase Doppler method general validity as applied to bubble diagnostics and promises to become a powerful research tool in the study of two phase flows.

Characterization of flow regimes in two phase flow using wavelet analysis

2018 ◽  
Author(s):  
Munzarin Morshed ◽  
Syed Imtiaz ◽  
Mohammad Aziz Rahman
Keyword(s):  
Wavelet Analysis ◽  
Two Phase Flow ◽  
Flow Regimes ◽  
Phase Flow ◽  
Two Phase

Small angle X-ray scattering study of porosity variation in a styrene-divinylbenzene copolymer

1981 ◽  
Vol 46 (7) ◽  
pp. 1675-1681 ◽  
Author(s):  
Josef Baldrian ◽  
Božena N. Kolarz ◽  
Henrik Galina
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Two Phase ◽  
X Ray ◽  
Porosity Variation ◽  
Swelling Agent ◽  
X Ray Scattering ◽  
Styrene Divinylbenzene ◽  
Ray Scattering

Porosity variations induced by swelling agent exchange were studied in a styrene-divinylbenzene copolymer. Standard methods were used in the characterization of copolymer porosity in the dry state and the results were compared with related structural parameters derived from small angle X-ray scattering (SAXS) measurements as developed for the characterization of two-phase systems. The SAXS method was also used for porosity determination in swollen samples. The differences in the porosity of dry samples were found to be an effect of the drying process, while in the swollen state the sample swells and deswells isotropically.

Characterization of alcohol/salt aqueous two-phase system for optimal separation of gallic acids

2021 ◽  
Vol 131 (5) ◽  
pp. 537-542
Author(s):  
Hui Suan Ng ◽  
Phei Er Kee ◽  
Hip Seng Yim ◽  
Joo Shun Tan ◽  
Yin Hui Chow ◽  
...  
Keyword(s):  
Phase System ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Optimal Separation

Characterization of Aqueous Two-Phase Systems from Volume and Density Measurements

2016 ◽  
Vol 61 (4) ◽  
pp. 1531-1539 ◽  
Author(s):  
Ehsan Atefi ◽  
Darcy Fyffe ◽  
Kerim B. Kaylan ◽  
Hossein Tavana
Keyword(s):  
Two Phase ◽  
Density Measurements ◽  
Aqueous Two Phase Systems ◽  
Phase Systems

Investigations into the Precessing Vortex Core Phenomenon in Cyclone Dust Separators

1994 ◽  
Vol 208 (2) ◽  
pp. 147-154 ◽  
Author(s):  
P Yazdabadi ◽  
A J Griffiths ◽  
N Syred
Keyword(s):  
Vortex Core ◽  
Reynolds Numbers ◽  
Frequency Parameter ◽  
Experimental Investigations ◽  
Swirl Number ◽  
Significant Drop ◽  
Precessing Vortex Core ◽  
Dust Separator ◽  
The Relationship

Experimental investigations have been carried out to examine the effect of downstream pipework configurations on the precessing vortex core (PVC) generated within the exhaust region of a cyclone dust separator. Characterization of the PVC using a non-dimensionalized frequency parameter (NDFP) was used to determine the relationship between Reynolds number and geometrical swirl number of the cyclone. The results show that the NDFP tends towards an asymptotic value for Reynolds numbers of about 50 000 and high swirl numbers (> 3.043). This value is reached earlier with lower swirl numbers. It was concluded that any exhaust pipework configuration produced a significant drop in the PVC frequency, and certain configurations either delayed or promoted the development of the PVC.

Sign in / Sign up

Export Citation Format

Share Document