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Masayuki Toda

Bio: Masayuki Toda is an academic researcher from Tohoku University. The author has contributed to research in topics: Particle & Plug flow. The author has an hindex of 3, co-authored 3 publications receiving 41 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors investigated the behavior of particles in pipe bends by the effect of gravitational and centrifugal forces and the secondary flow of fluid and found that both polystyrene and glass particles showed additional pressure drop, which was nearly constant regardless of the flow rate, similar to the case of horizontal pipe bends.
Abstract: Hydraulic transport of solid materials through pipe bends was investigated experimentally. Four kinds of 90° pipe bends of which the radii of curvature were 0, 12, 24 and 48cm, were made of polyacrylate pipe. The pressure drops were measured over sections of about 5 m, each including a pipe bend. The solid particles used in this experiment were glass beads (0.5-2.0mm diameter) and polystyrene particles (1.0mm diameter). The behavior of particles in pipe bends was found to be very much complicated by the effect of gravitational and centrifugal forces and the secondary flow of fluid. The results of the pressure-drop measurement were as follows, a) The horizontal pipe Bend : In the case of polystyrene particles, even though delivered particle concentration exceeded about 20%, the effect of particle concentration mc on the pressure drop did not appear to be the same as in the case of a straight pipeline. On the other hand, in the case of glass particles the additional pressure drop, which was nearly constant regardless of flow rate, increased with increasing particle concentration except where R=0 and 12cm. Moreover, the additional pressure drop was correlated by the dimensionless term Um2/gR (ρs/ρw-1) and mc. b) The vertical pipe bend : It was found from experiment that both polystyrene and glass particles showed additional pressure drop, which was nearly constant regardless of the flow rate, similar to the case of horizontal pipe bends.

19 citations

Journal ArticleDOI
TL;DR: In this article, the mean particle velocities in horizontal pipe, vertical pipe and pipe bends made of transparent polyacrylate pipe 30.2 mm in inside diameter were investigated experimentally.
Abstract: The mean particle velocities in horizontal pipe, vertical pipe and pipe bends made of transparent polyacrylate pipe 30.2 mm in inside diameter were investigated experimentally. The radii of curvature of the bends were 12, 24 and 48 cm, The solid particles used were glass beads which had a mean particle diameter of 0.189 cm and a density of 2.5 g/cm3. Radioactive particles were introduced as tracer and the particle velocities were determined by scintillation probes. The particle velocities in both the straight pipes and the bends are distributed in wide ranges, because the flow path of each particle in pipe is different. The particle velocity in vertical pipe is greater than that in horizontal pipe. The particle velocities in vertical bends with horizontal approach flow are in general smaller than those in the other bends. The effect of the radius of curvature on the particle velocity comes to be larger when the mean flow rate of slurry increases.

16 citations

Journal ArticleDOI
TL;DR: The limit-deposit velocity at which a solid deposit begins to build up in the bottom of a pipe is numerically analyzed on the basis of a two-dimensional flow model and a comparison is made with experimental results as discussed by the authors.
Abstract: The limit-deposit velocity at which a solid deposit begins to build up in the bottom of a pipe is numerically analyzed on the basis of a two-dimensional flow model and a comparison is made with experimental results. The model explains well the fact that the limit-deposit velocity increases with an increase in the delivered concentration of solids, and after reaching a maximum at a certain concentration it decreases gradually at higher concentrations. It is shown that, at lower solid concentrations, the shear stress acting on the surface of the bed of particles is the dominant factor for transporting the solids, while at higher concentrations the drag force of fluid within the bed plays a very important role.

9 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, a physical model for the prediction of the pressure drop and flow patterns is presented for the hydraulic transport of coarse particles in horizontal tubes, which is compared with new experimental data and shows good agreement.

182 citations

Journal ArticleDOI
TL;DR: In this paper, a method for displaying the range of existence of flow patterns in a solid-liquid pipeline is presented by means of flow maps drawn from the results of a phenomenological model.

157 citations

Journal ArticleDOI
TL;DR: In this paper, residence time distribution (RTD) of food particles in aseptic processing systems and the different experimental techniques used to gather RTD data as well as mathematical models used to describe RTD curves are discussed.

66 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used particle trajectories and velocity profiles of a single radioactively labelled tracer particle in high solid fraction, solid-liquid pipe flow to study solids conveying.

54 citations

Journal ArticleDOI
TL;DR: In this article, a comprehensive review of the existing knowledge on the fluid mechanics of two phase solid-liquid flows which largely emanates from the process engineering literature, and discusses its exploitation in continuous food processing is presented.

53 citations