Viscosity of Suspensions
About: This article is published in The Journal of the Society of Chemical Industry, Japan.The article was published on 1958-01-01 and is currently open access. It has received 8 citations till now. The article focuses on the topics: Relative viscosity & Viscosity.
Citations
More filters
TL;DR: A survey of the literature on the physical-mathematical modeling of debris flows can be found in this paper, where the authors discuss the basic aspects of their phenomenology, such as dilatancy, internal friction, fluidization, and particle segregation.
Abstract: A debris flow represents a mixture of sediment particles of various sizes and water flowing down a confined, channel-shaped region (e.g., gully, ravine or valley) down to its end, at which point it becomes unconfined and spreads out into a fan-shaped mass. This review begins with a survey of the literature on the physical-mathematical modeling of debris flows. Next, we discuss the basic aspects of their phenomenology, such as dilatancy, internal friction, fluidization, and particle segregation. The basic characterization of a debris flow as a mixture motivates the application of the continuum thermodynamical theory of mixtures to formulate a model for a debris flow as a viscous fluid-granular solid mixture. A major advantage of such a formulation, which goes beyond the most general models in the literature, e.g., Takahashi (1991), is that it can be used to expose and better understand the assumptions underlying existing models, as well as to derive new, more sophisticated models. Finally, we delve into the issue of how such models have been or can be implemented numerically, as well as general boundary conditions for debris flows.
148 citations
21 citations
TL;DR: In this paper, the authors used pulsed ultrasonic Doppler velocimetry to measure simultaneously the local velocity and the local concentration in a flow of solid-liquid suspension in a horizontal pipe.
Abstract: In this experimental study, the pulsed ultrasonic Doppler velocimetry was used to measure simultaneously the local velocity and the local concentration in a flow of solid-liquid suspension in a horizontal pipe. In order to distinguish between the Doppler signals coming from the continuous phase, water and those of the glass bead particles larger than the Kolmogorov length scale and the wavelength of the ultrasonic wave, a threshold is imposed on the integral of the power spectral density of the Doppler signal. The new approach measurement of the local concentration was used. It consists of counting a number NP of the Doppler signals of the solid particles crossing the measurement volume and a number NPt of the Doppler signals of the solid particles crossing the control volume. The concentration profile is then represented by the ration NP / NPt. The results obtained show that the suspension of fine particles, which represents a tracer, behaves as a homogenous fluid. For large particles, we confirmed the existence of the slip velocity and the effects of both concentration and size particle on the turbulence. The use of two distinct measurement volumes allows the direct determination of the turbulent length scales. The results show that the turbulence characteristics of the carried fluid are modified by the presence of the solid particles.
19 citations
TL;DR: In this article, an experimental method based on laser anemometry with Doppller effects is developed, which allows the measurement of velocities and their fluctuations in a flow of solid-liquid suspension in an ascendant vertical pipe.
Abstract: In this work, an experimental method based on laser anemometry with Doppller effects is developed. This allows the measurement of velocities and their fluctuations in a flow of solid-liquid suspension in an ascendant vertical pipe. In order to distinguish between the signals coming from the continuous phase, water, and those of the glass bead particles larger than the Kolmogorov length scale, an electronic logic circuit was incorporated in the measuring equipment. This enabled the study of both the slip velocity of the solid-liquid suspension and the influence of the large particles on turbulence. The results show that a fine particle suspension, which represents a tracer, behaves as a homogeneous fluid. For large particles, we confirmed the existence of a slip velocity and the effect of particle size on the turbulence. The use of two distinct measurement volumes produces good results for the direct measurement of the turbulent length scales. The results show that the presence of solid particles modifies the turbulence characteristics.
14 citations
TL;DR: In this paper, the effects of adding SiO2 or Al2O3 on the penetration characteristics of calcium ferrite (CF) melts into hematite substrate with different percentage of porosity were examined, and were discussed from the viewpoints of the relation to the solubility gap, viscosity and surface tension of the CF-based melts.
Abstract: Effects of adding SiO2 or Al2O3 on the penetration characteristics of calcium ferrite (CF) melts into hematite substrate with the different percentage of porosity were examined, and were discussed from the viewpoints of the relation to the solubility gap, ΔFe2O3 (mol%), viscosity and surface tension of the CF-based melts.In case of dense hematite substrate with 5% porosity, the penetration depth of CF melts into hematite substrate was depressed by the addition of SiO2 or Al2O3, and the addition of SiO2 was more effective than that of Al2O3. Moreover, the penetration of CF-based melts along grain boundaries into hematite substrate did not take place, and melts/hematite interface moved down by dissolution of solid hematite into these melts. The penetration depth of CF-based melts into hematite substrate was mostly determined by ΔFe2O3 (mol%), which meant that the dissolution of hematite into melts was rate-determine.In case of porous hematite substrate with 15% porosity, the penetration of CF-based melts along grain boundaries into hematite substrate occurred, and the penetration depth was 10 times deeper than the case of dense hematite substrate with 5% porosity for each slag. The penetration depth of CF melts was increased by the addition of SiO2 due to the decrease of melting temperature in the calcium ferrite system. The penetration depth of CF melts with the addition of Al2O3 was very similar to that of CF melts. These melts penetrated into hematite substrate with crystallization (solid) due to the increase of the melting temperature in calcium ferrite system by the dissolution of hematite into the liquid phase. The penetration depth of CF-based melts into hematite substrate was dominated by the ratio between the surface tension and viscosity of melts taking the suspension-corrected into consideration.
13 citations