Acoustic waves in two-fraction mixtures of gas with vapor, droplets and solid particles of different materials and sizes in the presence of phase transitions

Gubaidullin, D. A.; Nikiforov, A. A.; Utkina, E. A.

doi:10.1134/s001546281101008x

Cited by 15 publications

(2 citation statements)

References 9 publications

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“…Phase separation in two‐phase flows significantly alters the propagation pattern of acoustic waves leading to their dispersion and attenuation [ Bercovici and Michaut , ; Nigmatulin , ]. The presence of more than one dispersed phase results in additional phenomena such as the dependence of the dispersion relation on interaction forces and physical properties, volume fraction, and size distribution of particles [ Gubaidullin and Nigmatulin , ; Gubaidullin et al ., ; Ishii and Matsuhisa , ]. The accuracy of the “one‐particle size” approximation depends on the actual size distribution function and reduces with increasing standard deviation.…”

Section: One‐dimensional Acoustic Wavesmentioning

confidence: 99%

Two‐phase dynamics of volcanic eruptions: Particle size distribution and the conditions for choking

2015

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Explosive volcanic eruptions are studied using a two-phase model of polydisperse suspensions of solid particles in gas. Eruption velocities depend on choking conditions in the volcanic conduit, which depend on acoustic wave propagation that is, in turn, influenced by the particle size distribution in the two-phase mixture. The acoustic wave spectrum is divided into three regions of superfast short waves moving at the pure gas sound speed, purely attenuated domain at intermediate wavelengths, and slower long waves for a dusty pseudogas. The addition of solid phases with differing particle sizes qualitatively preserves the features of two-phase acoustic wave dispersion, although it narrows the regions of short-fast and intermediate-blocked waves. Choking conditions, however, strongly depend on the number and size distribution of solid phases. Changes in particle sizes lead to variations in the choking conditions, which determine the eruption velocities and the resulting height of the erupting column. Smaller particles always exit the choking point faster than big particles, as expected. Even though particle-particle interaction is neglected, the particle distributions influence each other by momentum exchange through the gas. Therefore, the structure of the dispersion relation as well as the eruption or choking velocities and subsequent column height and particle deposition bear information on how eruption dynamics are controlled by size distribution and relative volume fractions of small and big particles. We suggest that unimodal distributions, with one dominant small particle size, favor development of vertical plinian eruptions, while bimodal distributions, with a comparable mean size, lead to pyroclastic lateral flows.

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Section: One‐dimensional Acoustic Wavesmentioning

confidence: 99%

Two‐phase dynamics of volcanic eruptions: Particle size distribution and the conditions for choking

2015

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“…1 Therefore, it is difficult to predict the thermal efficiency and the power output of the steam turbines under such complicated conditions. According to the study, [2][3][4] when the sound wave enters the mixed medium, such as a vapor-liquid droplet mixture or a liquid with bubbles filled with a vapor-gas mixture, the sound wave will be reflected and refracted at the gas-liquid interface due to the different densities of the two media. There are a large number of small droplets in wet steam, and each droplet will have an important impact on the propagation and dissipation of sound waves, which is reflected in the macroscopic changes in the sonic speed of wet steam.…”

Section: Introductionmentioning

confidence: 99%

Experimental validation of sonic speed theory for wet steam

Zhang

Wu²,

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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In order to obtain the sonic speed of the wet steam under different thermal conditions, and verify the accuracy and the precision of Petr’s wet steam sonic theory, experimental measurements were carried out. Also, the effects of acoustic frequency, pressure, wetness, and droplet size on the sonic speed of wet steam were studied based on Petr’s wet steam sonic theory. Results indicate that deviations between the experimental results and Petr’s wet steam sonic theory is in the range of −4%–4%, which is within the experimental measurement error of ±5%. The variation range of the ratio of the actual sonic speed a to the frozen speed af is 0.89–1. When the sonic speed ratio ( a/ af) is close to 1, it means that the sonic speed of wet steam is close to the frozen speed, and the faster the sound wave propagates in the wet steam. In the acoustic frequency range of 102–105 Hz, the sonic speed of wet steam increases with increase of acoustic frequency, pressure, and water droplet size, and decreases with increasing wetness.

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