著者

清水 賀之 畠山 信夫 花村 英悟 渡部 一雄 横山 由香 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.135, no.7, pp.52-62, 2019-07-31 (Released:2019-07-05)

参考文献数

17

被引用文献数

1

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Flow characteristics of slurry with rare-earth rich mud are investigated to examine lifting systems for mining rare-earth elements from deep seabed. Twelve samples, extracted from different locations and depths from seabed around the Minamitorishima with several concentration of rare-earth elements are mixed up with sea water to make slurry with specified volume concentration of mud 1.0% to 10.0%. Cone-plate type rotary viscometers are used to examine relations between shear stress and shear rate of slurry in each volume concentration of mud. As a result, it was found that shape of graph; the shear stress in the vertical axis and the shear rate in the horizontal axis was concave down and increasing during whole range of the shear rate. The shear stress increased gradually as the shear rate increased in case of low volume concentration of mud up to 3.0%. On the other hand, the shear stress changed significantly at small shear rate, and then gradually increased, then lineally in the end in case of larger volume concentration. In addition, similar characteristics under the same volume concentration, even though tested samples were extracted from different locations, depths and concentration of rare-earth elements. Further, three types of fluid model; the Power low model, the Bingham-Papanastasiou model and the Herchel-Bulkley-Papanastasiou model were fitted on the data using the least square techniques, then compared with each other. The last two models, i.e., the Bingham-Papanastasiou model and the Herchel-Bulkley-Papanastasiou model corrects deviations from the data when using “original” the Bingham model and the Herchel-Bulkley model, especially in the range of small shear rate under high volume concentration of mud. The Herchel-Bulkley-Papanastasiou model was the most appropriate model within the three models. Furthermore, correlation equations for parameters of the HerchelBulkley-Papanastasiou model were derived related to volume concentration of mud.

著者

畠山 信夫 清水 賀之 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.136, no.5, pp.40-51, 2020-05-31 (Released:2020-05-29)

参考文献数

11

被引用文献数

1

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The mud flow between the borehole and the drill pipe in well drilling can be regarded as the flow of nonNewtonian fluids through a concentric annulus. In recent years, the Herschel-Bulkley rheological model is recommended as a general fluid model of drilling mud because it encompasses the power law model and the Bingham plastic model. Also, in the field of well drilling, the flow through a concentric annulus is conventionally approximated by the flow between two parallel plates. However, its applicability does not seem to be examined because it is not easy to perform analysis of non-Newtonian fluid flow through a concentric annulus. For studies on laminar flow of viscoplastic fluids (fluids with yield stress) through concentric annuli, there are researches on Bingham fluid by Fredrickson & Bird and on Herschel-Bulkley fluid by Hanks. Since the equation of motion in viscoplastic fluid flow through a concentric annulus cannot be analytically solved in all of them, in their researches numerical calculations are presented by charts. However, it is not simple as a method to estimate the frictional pressure loss, because multiple charts are related. In this research, based on the results of previous authors' research7, 8), we investigate a method that can easily calculate the average wall shear-stress in laminar flows of viscoplastic fluids through concentric annuli. That is, using the results of circular pipe and parallel-plate, an approximate expression of viscosity factor in viscoplastic fluid flow through concentric annuli is derived and the error of the average wall shear-stress represented by the approximate equation is evaluated. Furthermore, a simpler approximate formula which can be calculated directly without numerical calculation is derived and its error is also evaluated. In addition, error assessment is performed to confirm the applicability of approximation by the flow in the parallel-plate for the flow in a concentric annulus, which has been conventionally done in the field of well drilling.

著者

畠山 信夫 清水 賀之 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.135, no.2, pp.15-24, 2019-02-28 (Released:2019-02-28)

参考文献数

16

被引用文献数

1

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The rheological properties of cement slurries (including fresh concrete and high concentration paste for filling etc.) are complicated, therefore they are approximated by the Bingham plastic model. In recent years, the application of Herschel-Bulkley model is recommended for drilling mud. The rheological coefficients of these models are obtained by using measurement results of the rotational viscometer or experimental results of the flow in a circular pipe, and the pressure loss in pipe flows is obtained from these rheological coefficients. Therefor it is essential to properly select the model in order to design the slurry transportation. In the field of well drilling, the flow in a concentric annulus with a relatively large pipe diameter ratio is approximated by the flow in a parallelplate, so it is also necessary to consider the flow in a parallel-plate. In this study, first, a method to determine the rheological coefficients by the least squares method from measurement results of the rotational viscometer using the function provided in a spreadsheet is shown and a method to quantitatively select the rheological model using Akaike's information criterion is also shown. Next, after the exact solutions of flows in a circular pipe and in a parallel-plate is summarized, an approximate expression of wall shear stress is derived and the error analysis is performed, and its effectiveness is confirmed by using past experimental data. In addition, a method of calculating the rheological coefficients by the least squares method from measurement results of flows in a circular pipe and in a parallel-plate using spreadsheet is shown and this method is practiced by using the experimental data of the flow in pipes.

著者

清水 賀之 畠山 信夫 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.10, pp.142-150, 2018-10-31 (Released:2018-10-26)

参考文献数

21

被引用文献数

4

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A numerical analysis is conducted to examine an air-lift pumping system for mining rare-earth rich mud under 6000m deep seabed around the Minami-Tori-Shima. The numerical scheme in the analysis adopts the one-dimensional drift-flux model, which solves pressure and velocities as well as volumetric fractions of each phase in the air-slurry two-phase flow along a lifting pipe. The empirical formulas derived from experiments using rare-earth rich mud around the Minami-Tori-Shima estimate the pseudoplastic viscosity and the rheology constant as a function of volumetric concentration of mud in slurry. They are devised in the scheme to evaluate the pressure drop in air-slurry two-phase flow as the power-law fluid. Parametric studies were conducted to examine steady characteristics of the air-lift pumping system by changing the air flow rate, the water depth where the air was injected and back pressure. As a result, the basic characteristics of the air-lift pumping system were clarified. For example, with the air flow rate of 6kg/s, depth of water where air was injected of 3000m, back pressure of 0.2MPa (G), 6040m lifting pipe out of which 6000m is submerged, and 40m is above sea level, pipe diameter below the depth where the air was injected of 0.15m and above that depth 0.2m, it was found that the maximum mud flow rate was 1.01x103t/d, volumetric concentration of mud was 6.2%, slurry velocity was 3.8m/s, mixture velocity at the exit of the lifting pipe was 52m/s and power required was 2.0x103kW. In addition it was found that the performance of the system decreases when using the scheme as the power-law fluid compared with the one using the Mori-Ototake formula as Newtonian fluid. Furthermore, specifying back pressure is useful because of increased efficiency of the system, as well as for keeping the mixture velocity down at the exit of the lifting pipe.

著者

畠山 信夫 清水 賀之 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.134, no.2, pp.31-40, 2018-02-01 (Released:2018-02-27)

参考文献数

33

被引用文献数

1

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One of the authors has developed a numerical simulator of airlift pump to solve governing equations represented by the drift flux model. The solver is based on the finite volume method which is known as SIMPLER algorithm for numerical scheme. The calculated results using the simulator were comparatively in good agreement with experimental ones by Weber et al. and Saito et al., despite lack of appropriate correlations used in the constitutive equations. In this study, the simulator is improved by a recent study (Ishii and Hibiki, 2011) on the constitutive equations of the drift flux model in the gas-liquid two-phase flow. The effect of newly incorporated correlations versus original ones in the constitutive equations is studied on the lifting characteristics such as relation between inputting air and lifted water. Also, flow characteristics along axial direction of pipes are examined to compare numerical results with experimental ones over wide range of pipe diameter and pipe length. Furthermore, pressure losses are grasped from the standpoint of the pump head, the relation between various pressure losses and lifting characteristics is discussed.

著者

畠山 信夫 清水 賀之 益山 忠

出版者

一般社団法人 資源・素材学会

雑誌

Journal of MMIJ (ISSN:18816118)

巻号頁・発行日

vol.133, no.7, pp.157-164, 2017-07-19 (Released:2017-07-19)

参考文献数

8

被引用文献数

2

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The flow through annuli is encountered in drilling operation, in which drilling mud flows between the borehole wall and the drilling pipe. Some drilling muds, depending on their prepared materials, exhibit nonNewtonian characteristics and in many cases may be regarded as pseudoplastic fluids. This study examines the dimensionless flow rate defined by Fredrickson and Bird (Fredrickson and Bird, 1958) on pseudoplastic fluid laminar flow in concentric annuli. A new approximation function is derived to evaluate the viscosity factor, also easy to use without numerical procedures. The function is more precise than the one, which was previously shown by the authors (Masuyama and Hatakeyama, 2003). Further, a new scheme is proposed to evaluate the characterizing coefficients, such as the pseudoplastic viscosity and the rheology constant using flow data. Furthermore, generalized formulas of the Reynolds number and the pipe friction coefficient for pseudoplastic fluid are shown for concentric annuli in order to calculate the pressure drop. They are extendable in the case of circular pipes, also parallel plates.