Time-Average Molecular Rayleigh Scattering Technique for Measurement of Velocity, Density, Temperature, and Turbulence Intensity in High Speed Nozzle Flows

2004 ◽  
Author(s):  
Amy Mielke ◽  
Richard Seasholtz ◽  
Kristie Elam ◽  
Jayanta Panda
Keyword(s):  
Turbulence Intensity ◽  
High Speed ◽  
Rayleigh Scattering ◽  
Scattering Technique ◽  
Time Average ◽  
Nozzle Flows

The Effect of Lewis Number on Instantaneous Flamelet Speed and Position Statistics in Counter-Flow Flames With Increasing Turbulence

2017 ◽  
Author(s):  
Sean D. Salusbury ◽  
Ehsan Abbasi-Atibeh ◽  
Jeffrey M. Bergthorson
Keyword(s):  
Flame Front ◽  
Turbulence Intensity ◽  
High Speed ◽  
Rayleigh Scattering ◽  
Turbulent Flame ◽  
Lewis Number ◽  
Turbulent Flames ◽  
Flame Speed ◽  
Laminar Flames ◽  
Counter Flow

Differential diffusion effects in premixed combustion are studied in a counter-flow flame experiment for fuel-lean flames of three fuels with different Lewis numbers: methane, propane, and hydrogen. Previous studies of stretched laminar flames show that a maximum reference flame speed is observed for mixtures with Le ≳ 1 at lower flame-stretch values than at extinction, while the reference flame speed for Le ≪ 1 increases until extinction occurs when the flame is constrained by the stagnation point. In this work, counter-flow flame experiments are performed for these same mixtures, building upon the laminar results by using variable high-blockage turbulence-generating plates to generate turbulence intensities from the near-laminar u′/SLo=1 to the maximum u′/SLo achievable for each mixture, on the order of u′/SLo=10. Local, instantaneous reference flamelet speeds within the turbulent flame are extracted from high-speed PIV measurements. Instantaneous flame front positions are measured by Rayleigh scattering. The probability-density functions (PDFs) of instantaneous reference flamelet speeds for the Le ≳ 1 mixtures illustrate that the flamelet speeds are increasing with increasing turbulence intensity. However, at the highest turbulence intensities measured in these experiments, the probability seems to drop off at a velocity that matches experimentally-measured maximum reference flame speeds in previous work. In contrast, in the Le ≪ 1 turbulent flames, the most-probable instantaneous reference flamelet speed increases with increasing turbulence intensity and can, significantly, exceed the maximum reference flame speed measured in counter-flow laminar flames at extinction, with the PDF remaining near symmetric for the highest turbulence intensities. These results are reinforced by instantaneous flame position measurements. Flame-front location PDFs show the most probable flame location is linked both to the bulk flow velocity and to the instantaneous velocity PDFs. Furthermore, hydrogen flame-location PDFs are recognizably skewed upstream as u′/SLo increases, indicating a tendency for the Le ≪ 1 flame brush to propagate farther into the unburned reactants against a steepening average velocity gradient.

Application of a photodimerizable probe to the forced Rayleigh scattering technique for measurement of self-diffusion of polymer chains

Polymer ◽  
1986 ◽  
Vol 27 (11) ◽  
pp. 1705-1708 ◽  
Author(s):  
Qui Tran-Cong ◽  
Taihyun Chang ◽  
Charles C. Han ◽  
Yasunori Nishijima
Keyword(s):  
Rayleigh Scattering ◽  
Polymer Chains ◽  
Self Diffusion ◽  
Scattering Technique

Study on the interaction between emodin and ethyl violet by resonance Rayleigh scattering technique

RSC Advances ◽  
2014 ◽  
Vol 4 (64) ◽  
pp. 34204-34209 ◽  
Author(s):  
Ernv Wang ◽  
Jidong Yang ◽  
Donghai Yu
Keyword(s):  
Rayleigh Scattering ◽  
Resonance Rayleigh Scattering ◽  
Ethyl Violet ◽  
Scattering Technique

EV-EMO system. CEMO(1–8) 0, 0.4, 1.0, 1.5, 2.3, 3.2, 3.8, 4.2 μg mL−1; CEV: 1.2 × 10−5 mol L−1; pH 7.0.

Second order nonlinear optical properties of corroles: experimental and theoretical investigations

2012 ◽  
Vol 16 (12) ◽  
pp. 1276-1284 ◽  
Author(s):  
Xiao Ying ◽  
Xiao-Yan Long ◽  
Mian HR Mahmood ◽  
Quan-Yuan Hu ◽  
Hai-Yang Liu ◽  
...  
Keyword(s):  
Excited States ◽  
Rayleigh Scattering ◽  
Soret Band ◽  
Incident Wavelength ◽  
Maximum Value ◽  
Theoretical Investigations ◽  
Scattering Technique ◽  
Donor Acceptor ◽  
Neglect Of Differential Overlap ◽  
Good Agreement

The first hyperpolarizabilities, βHRS, of corrole derivatives have been measured by using Hyper–Rayleigh Scattering technique. The results showed that βHRS of corroles could be greatly enhanced by modifying its periphery with donor–acceptor groups. Maximum value reaches 354 × 10-30 esu at an incident wavelength of 1500 nm. βHRS of investigated corroles were also calculated with the Zerner's intermediate neglect of differential overlap/configuration interaction/sum-over-states method. The calculated and experimental results are in good agreement and conclude that βHRS arises mainly from the charge transfer along molecule's non-symmetrical axis and strong coupling between two different excited states of the Soret band.

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