Concentration fields in a confined two-gas mixture and engine in-cylinder flow: laser tomography measurement by Mie scattering

Guibert, Philippe; Durget, M.; Murat, Miraç

doi:10.1007/s003480100309

Cited by 11 publications

(5 citation statements)

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“…In particular, the effect of Mie light scattering by particles was used to determine the particle spatial distribution in the flow (see, e.g., [72]). In the experiments we probed the central 212 × 212 mm 2 region in the chamber.…”

Section: Experimental Set-upmentioning

confidence: 99%

Tangling clustering of inertial particles in stably stratified turbulence

et al. 2010

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We have predicted theoretically and detected in laboratory experiments a new type of particle clustering (namely, tangling clustering of inertial particles) in a stably stratified turbulence with imposed mean vertical temperature gradient. In the stratified turbulence a spatial distribution of the mean particle number density is nonuniform due to the phenomenon of turbulent thermal diffusion, i.e., the inertial particles are accumulated in the vicinity of the minimum of the mean temperature of the surrounding fluid, and a non-zero gradient of the mean particle number density, ∇N , is formed. It causes generation of fluctuations of the particle number density by tangling of the large-scale gradient, ∇N , by velocity fluctuations. In addition, the mean temperature gradient, ∇T , produces the temperature fluctuations by tangling of the large-scale gradient, ∇T , by velocity fluctuations. The anisotropic temperature fluctuations contribute to the two-point correlation function of the divergence of the particle velocity field, i.e., they increase the rate of formation of the particle clusters in small scales. We have demonstrated that in the laboratory stratified turbulence this tangling clustering is much more effective than a pure inertial clustering (preferential concentration) that has been observed in isothermal turbulence. In particular, in our experiments in oscillating grid isothermal turbulence in air without imposed mean temperature gradient, the inertial clustering is very weak for solid particles with the diameter ≈ 10 µm and Reynolds numbers based on turbulent length scale and rms velocity, Re = 250. In the experiments the correlation function for the inertial clustering in isothermal turbulence is much smaller than that for the tangling clustering in nonisothermal turbulence. The size of the tangling clusters is of the order of several Kolmogorov length scales. The clustering described in our study is found for inertial particles with small Stokes numbers and with the material density that is much larger than the fluid density. Our theoretical predictions are in a good agreement with the obtained experimental results.

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Section: Experimental Set-upmentioning

confidence: 99%

Tangling clustering of inertial particles in stably stratified turbulence

et al. 2010

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“…Particle spatial distribution is determined using PIV system. In particular, the effect of the Mie light scattering by particles was used to determine the particle spatial distribution in the flow [55]. The mean intensity of scattered light was determined in 40 × 32 interrogation windows with the size 32 × 32 pixels.…”

Section: Methodsmentioning

confidence: 99%

Experimental study of turbulent thermal diffusion of particles in inhomogeneous and anisotropic turbulence

Elmakies,

Shildkrot,

Kleeorin

et al. 2022

Preprint

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We study experimentally turbulent thermal diffusion of small particles in inhomogeneous and anisotropic stably stratified turbulence produced by one oscillating grid in the air flow. The velocity fields have been measured using a Stereoscopic Particle Image Velocimetry (PIV). We have determined various turbulence characteristics: the mean and turbulent velocities, two-point correlation functions of the velocity field and an integral scale of turbulence from the measured velocity fields. The temperature field have been measured with a temperature probe equipped with 12 E thermocouples. Spatial distributions of micron size particles have been determined by a PIV system using the effect of the Mie light scattering by particles in the flow. The experiments have demonstrated that particles are accumulated at the minimum of mean fluid temperature due to phenomenon of turbulent thermal diffusion. Using measured spatial distributions of particles and temperature fields, we have determined the effective turbulent thermal diffusion coefficient of particles in inhomogeneous temperature stratified turbulence. This experimental study has clearly detected phenomenon of turbulent thermal diffusion in inhomogeneous turbulence.

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“…In this experimental study we use methods of measurements applied previously in different studies of turbulent transport of particles (for details see [25,26,27]). In particular, we use PIV and an Image Processing Technique based on the analysis of the intensity of the Mie scattering to determine the spatial distribution of tracer particles (see, e.g., [28]). As a tracer we use smoke produced by incense particles sublimation.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…In particular, we use PIV and an Image Processing Technique based on the analysis of the intensity of the Mie scattering to determine the spatial distribution of tracer particles (see, e.g., [28]). As a tracer we use smoke produced by incense particles sublimation.…”

Section: Experimental Set-upmentioning

confidence: 99%

Mixing at the External Boundary of a Submerged Turbulent Jet

Eidelman¹,

Elperin²,

Kleeorin³

et al. 2009

Springer Proceedings in Physics

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We study experimentally and theoretically mixing at the external boundary of a submerged turbulent jet. In the experimental study we use Particle Image Velocimetry and an Image Processing Technique based on the analysis of the intensity of the Mie scattering to determine the spatial distribution of tracer particles. An air jet is seeded with the incense smoke particles which are characterized by large Schmidt number and small Stokes number. We determine the spatial distributions of the jet fluid characterized by a high concentration of the particles and of the ambient fluid characterized by a low concentration of the tracer particles. In the data analysis we use two approaches, whereby one approach is based on the measured phase function for the study of the mixed state of two fluids. The other approach is based on the analysis of the two-point second-order correlation function of the particle number density fluctuations generated by tangling of the gradient of the mean particle number density by the turbulent velocity field. This gradient is formed at the external boundary of a submerged turbulent jet. We demonstrate that PDF of the phase function of a jet fluid penetrating into an external flow and the two-point second-order correlation function of the particle number density do not have universal scaling and cannot be described by a power-law function. The theoretical predictions made in this study are in a qualitative agreement with the obtained experimental results.

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Concentration fields in a confined two-gas mixture and engine in-cylinder flow: laser tomography measurement by Mie scattering

Cited by 11 publications

References 0 publications

Tangling clustering of inertial particles in stably stratified turbulence

Tangling clustering of inertial particles in stably stratified turbulence

Experimental study of turbulent thermal diffusion of particles in inhomogeneous and anisotropic turbulence

Mixing at the External Boundary of a Submerged Turbulent Jet

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