Temperature and velocity determination of shock-heated flows with non-resonant heterodyne laser-induced thermal acoustics

Förster, Felix J.; Baab, Steffen; Lamanna, Grazia; Weigand, Bernhard

doi:10.1007/s00340-015-6217-7

Cited by 23 publications

(14 citation statements)

References 55 publications

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“…Three different atmospheres, namely nitrogen with a purity of 99.999 % , argon with a purity of 99.998 % , and carbon dioxide with a purity of 99.995 % , are studied. The optical setup is adapted from the one described in Baab et al (2016) and Förster et al (2015).…”

Section: Experimental Facility and Measurement Techniquementioning

confidence: 99%

On the potential and challenges of laser-induced thermal acoustics for experimental investigation of macroscopic fluid phenomena

et al. 2020

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Mixing and evaporation processes play an important role in fluid injection and disintegration. Laser-induced thermal acoustics (LITA) also known as laser-induced grating spectroscopy (LIGS) is a promising four-wave mixing technique capable to acquire speed of sound and transport properties of fluids. Since the signal intensity scales with pressure, LITA is effective in high-pressure environments. By analysing the frequency of LITA signals using a direct Fourier analysis, speed of sound data can be directly determined using only geometrical parameters of the optical arrangement no equation of state or additional modelling is needed at this point. Furthermore, transport properties, like acoustic damping rate and thermal diffusivity, are acquired using an analytical expression for LITA signals with finite beam sizes. By combining both evaluations in one LITA signal, we can estimate mixing parameters, such as the mixture temperature and composition, using suitable models for speed of sound and the acquired transport properties. Finally, direct measurements of the acoustic damping rate can provide important insights on the physics of supercritical fluid behaviour. Graphic Abstract

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Section: Experimental Facility and Measurement Techniquementioning

confidence: 99%

On the potential and challenges of laser-induced thermal acoustics for experimental investigation of macroscopic fluid phenomena

et al. 2020

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“…To date, the main efforts to provide such a pressure measurement tool have concentrated on the application of laserinduced thermal-acoustics (LITA) and laser-induced thermal grating spectroscopy (LITGS). [14][15][16][17][18][19] Although these methods have successfully demonstrated their applicability in pressure and temperature measurement, they do have some limitations. More specifically, because they are dependent on the laser radiation absorption and subsequent acoustic wave generation, they work well at high pressures (typically above 2 atm) while only one such method has demonstrated its applicability at a pressure below 100 Torr.…”

Section: A)mentioning

confidence: 99%

Remote-sensing gas measurements with coherent Rayleigh-Brillouin scattering

Gerakis

Shneider

Stratton

2016

Applied Physics Letters

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We measure the coherent Rayleigh-Brillouin scattering (CRBS) signal integral as a function of the recorded gas pressure in He, Co 2 , SF 6 , and air, and we confirm the already established quadratic dependence of the signal on the gas density. We propose the use of CRBS as an effective diagnostic for the remote measurement of gas' density (pressure) and temperature, as well as polarizability, for gases of known composition. Published by AIP Publishing.

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“…4. Note again that it is adapted from earlier versions of the setup described in Förster et al (2015) and Baab et al (2016). The description here is, therefore, limited to the essentials like the wavelengths of the excitation ( = 1064 nm ) and interrogation beams ( = 532 nm ).…”

Section: Optical Setupmentioning

confidence: 99%

“…The corresponding constant of proportionality is found in a calibration experiment using a system with known thermodynamic properties. The calibration procedure is identical to the one in Förster et al (2015), where the effect of uncertainties from the calibration is found to be within 1.3%. One of the important features of LITA is that this characteristic frequency is also found if the LITA is heavily deteriorated by scattering events caused for instance by inhomogeneous density fields along the beam path lengths and turbulence.…”

Section: Post-processingmentioning

confidence: 99%

Mixing characterization of highly underexpanded fluid jets with real gas expansion

et al. 2018

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We report a comprehensive speed of sound database for multi-component mixing of underexpanded fuel jets with real gas expansion. The paper presents several reference test cases with well-defined experimental conditions providing quantitative data for validation of computational simulations. Two injectant fluids, fundamentally different with respect to their critical properties, are brought to supercritical state and discharged into cold nitrogen at different pressures. The database features a wide range of nozzle pressure ratios covering the regimes that are generally classified as highly and extremely highly underexpanded jets. Further variation is introduced by investigating different injection temperatures. Measurements are obtained along the centerline at different axial positions. In addition, an adiabatic mixing model based on non-ideal thermodynamic mixture properties is used to extract mixture compositions from the experimental speed of sound data. The concentration data obtained are complemented by existing experimental data and represented by an empirical fit.

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Temperature and velocity determination of shock-heated flows with non-resonant heterodyne laser-induced thermal acoustics

Cited by 23 publications

References 55 publications

On the potential and challenges of laser-induced thermal acoustics for experimental investigation of macroscopic fluid phenomena

On the potential and challenges of laser-induced thermal acoustics for experimental investigation of macroscopic fluid phenomena

Remote-sensing gas measurements with coherent Rayleigh-Brillouin scattering

Mixing characterization of highly underexpanded fluid jets with real gas expansion

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