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Shigemori Ohtani

Bio: Shigemori Ohtani is an academic researcher from Tohoku University. The author has contributed to research in topics: Thermal diffusivity & Carbonization. The author has an hindex of 8, co-authored 37 publications receiving 235 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, an optical method is applied to measure the average velocity of solid particles transported vertically by a turbulent air stream, which is based on cross-correlating the signals of two photo-sensors.

34 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss permeability, Osmotic Suction Pressure (OSP), and permability in the context of OSPs and show how to use them.
Abstract: 収縮性材料の乾燥に関して粘土を例に取りその機械的諸特性値 (ヤング率, 引張り強度, 降伏応力) ならびに輸送特性値 (Permeability, Osmotic Suction Pressure) の含水率依存性を実験的に求めた.収縮性材料内の水分移動に関して, 土質力学における圧密理論に基づき, Osmotic Suction Pressureの勾配の他に応力勾配をも移動の駆動力として考慮すべきであることを示した.計算から求められた局所含水率の時間変化は実測値と良く一致した.さらに, 応力分布の計算結果から乾燥速度の増加に伴い材料内で大きな引張り応力が発生することが明らかとなった.

18 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss osmotic suction pressure and osmosis in the context of OSSP, and show that it can be used to improve the performance of ossification.
Abstract: 水分移動に関して, osmotic suction pressureの勾配の他に応力勾配をも考慮し, 乾燥中の含水率および応力変化を有限要素法で計算した.乾燥実験から求められた局所含水率の時間変化は計算値と比較的よく一致した.更に, 応力分布の計算結果から乾燥速度の増加に伴い乾燥表面で大きな引張り応力が発生し, 内部は圧縮応力となるが, ある場合には材料内部で引張り応力となる事も示された.また, ガラス粒子を混合すると発生する応力値を木節粘土に比べて少さく抑える事ができ, 乾燥割れが生じにくくなる可能性が示された.

17 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of moisture content on Liquid transport properties (Permeability and suction pressure) and mechanical properties (Young's modulus, yield stress and tensile strength) of drying shrinkage materials (Kibnshi, IIaido and mixed clay) were measured.
Abstract: Effects of moisture content on Liquid transport properties (Permeability and suction pressure) and mechanical properties (Young's modulus, yield stress and tensile strength) of drying shrinkage materials (Kibnshi, IIaido and mixed clay) were measured and a strong dependence was found. When glass beads are added to the Kibushi, permeability increase and Young's modulus and yield stress decrease in spite of the same suction pressure and tensile strength. Changes in local moisture content and stress during drying was calculated by using finite-element method, taking into account the stress gradient in addition to the pressure gradient due to osmotic suction.

12 citations


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TL;DR: In this article, it was shown that at angles up to about 80°, the fluid flows mainly along the furrows on each plate and a secondary, swirling motion is imposed on the flow along a furrow when its path is crossed by streams flowing along furrows along the opposite wall.

354 citations

Journal ArticleDOI
TL;DR: In this article, the generalized Leveque equation was used to predict the heat transfer coefficient of a plate and frame heat exchanger with chevron corrugation pattern, which is the most important design parameter with respect to fluid friction and heat transfer.
Abstract: Manufacturers of plate and frame heat exchangers nowadays mainly offer plates with chevron (or herringbone) corrugation patterns. The inclination angleof the crests and furrows of that sinusoidal pattern relative to the main flow direction has been shown to be the most important design parameter with respect to fluid friction and heat transfer. Two kinds of flow may exist in the gap between two plates (pressed together with the chevron pattern of the second plate turned into the opposite direction): the crossing flow of small substreams following the furrows of the first and the second plate, respectively, over the whole width of the corrugation pattern, dominating at lower inclination angles (lower pressure drop); and the wavy longitudinal flow between two vertical rows of contact points, prevailing at highangles (high pressure drop). The combined effects of the longer flow paths along the furrows, the crossing of the substreams, flow reversal at the edges of the chevron pattern, and the competition between crossing and longitudinal flow are taken into account to derive a relatively simple but physically reasonable equation for the friction factor ξ as a function of the angleand the Reynolds number Re. Heat-transfer coefficients are then obtained from a theoretical equation for developing thermal boundary layers in fully developed laminar or turbulent channel flow — the generalized Leveque equation — predicting heat-transfer coefficients as being proportional to (ξ·Re2)1/3. It is shown, by comparison, that this prediction is in good agreement with experimental observations quoted in the literature.

343 citations

Journal ArticleDOI
TL;DR: Experimental shrinkage data as a function of water content for particles of potatoes, apples and carrots of different geometry and under various drying conditions are presented in this paper, where a simple model in which volumetric ratio is represented by one or two line segments is developed.

290 citations

Journal ArticleDOI
Yong Yan1
TL;DR: A detailed and comprehensive review of the techniques and the current state of knowledge and experience can be found in this article, where the techniques are classified under three main categories: direct measurement of mass flow rates, measurement of volumetric concentrations of solids and measurement of solid velocity.
Abstract: Many types of techniques for metering the mass flow rate of bulk solids in a pneumatic pipeline have been proposed and developed during the past 20 years. This paper presents a detailed and comprehensive review of the techniques and the current state of knowledge and experience. The techniques are classified under three main categories: direct measurement of solids mass flow rates, measurement of volumetric concentrations of solids and measurement of solids velocity. Future developments and possible trends in this field are also included.

265 citations

Journal ArticleDOI
TL;DR: In this paper, a literature search is presented on plate heat exchangers and new correlations for evaporation heat transfer coefficient and friction factor are introduced, which are applicable to various system pressure conditions and plate chevron angles.
Abstract: Plate heat exchangers are used regularly in the heating, ventilating, air conditioning, and refrigeration industry. There is an urgent need for detailed and systematic research regarding heat transfer and the fluid flow characteristics of these types of exchangers. As an initiative in this respect, a literature search is presented on plate heat exchangers. New correlations for evaporation heat transfer coefficient and friction factor are introduced, which are applicable to various system pressure conditions and plate chevron angles. The correlations are based on actual field data collected during several years of installation and operation of chillers, and they are intended to serve as design tools and perhaps as a starting point for future research.

243 citations