Use of dimensional similitude for scale-up of hydrodynamics in three-phase fluidized beds

“…For the curved pipe flow of a Kaolin clay slurry, Tada et al (1994) developed a method to identify the friction factor using the Dean number (Reynolds number times the square root of the ratio of the radius of the pipe to its radius of curvature). In a three-phase fluidized bed, Safoniuk et al (1999) proposed five dimensionless groups that must match to ensure dynamic similitude. These groups included the M-group, Eotvus number, Reynolds number, density ratio, and velocity ratio.…”

Section: Multiphase Flowmentioning

confidence: 99%

Waste Tank Size Determination for the Hanford River Protection Project Cold Test, Training, and Mockup Facility

Onishi¹,

Wells²,

Kuhn³

2001

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SummaryHanford River Protection Project (RPP) staff will use the planned Cold Test, Training, and Mockup Facility (CTMF) to test the ability to retrieve tank waste using mixer pumps and fluidic mixers. The staff will conduct hydraulic tests to evaluate waste mobilization (verify the effective cleaning radius), waste suspension (verify the homogeneity of mixed solids), and hydraulic forces acting on tank internal structures (instrumentation trees and airlift circulators). The purpose of the study reported herein is to determine which tank size (30, 55, or 75 ft diameter) and waste depth (10, 20, or 30 ft) should be used for the CTMF model tank so the test results will best predict the corresponding mixing behavior in actual Hanford double-and single-shell tanks.The literature review on dynamic similarity criteria for hydrodynamic mixing and associated phenomena indicated that there was very little information available on the similitude of nonNewtonian slurry mixing. Thus we derived similarity criteria that, if met during testing, would dynamically reproduce double-and single-shell tank waste mixing for retrieval of Hanford tank waste. The nondimensional similarity parameters, in roughly descending order of importance, are jet Reynolds number, solid erosion criterion, densimetric Froude number, Rouse number for suspended sediment distribution, and particle Reynolds number.We evaluated four specific cases to illustrate the difficulties of obtaining appropriate liquid and solid properties to satisfy these similarity criteria. These four cases are AN-102 and AZ-102, representing low-activity and high-activity wastes, respectively, and their variations having a 275-µm diameter and 3,000-kg/m 3 solids density. Although we found 25 combinations of material properties that would satisfy or nearly satisfy some of the similarity criteria for these four cases, the study indicated that, with 35-and 55-ft scale models,• It is not theoretically possible, except in two specific cases for the 35-ft model tank.• It is not practical to obtain and conduct physical modeling with the required fluids and solids.• When it is possible to obtain some limited similitude, it is not useful in most of these cases.The solid transport, deposition, and erosion are very complex phenomena and require that a physical model be calibrated to reproduce the important prototype (actual tank) conditions (e.g., solid erosion and concentration). The lack of calibration data (except for AZ-101 pump mixing test data) requires the CTMF model tank testing to satisfy the strict similitude requirements presented above. Only the full-scale CTMF model tank with a 30-ft waste depth will satisfy all these similarity criteria for all the conditions. Thus, we recommend using a 75-ft-diameter and 30-ft-deep (full-scale) tank model for the CTMF, as a general model applicable to a wide range of waste and retrieval operational conditions.The CTMF test data can also be used to validate numerical simulation models. Validated computer models may, in turn, produce results t...

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“…Similitude analysis has been successfully applied to multiphase flow systems, such as fluidized beds [25,26], gasliquid bubble columns [27], and gas-liquid-solid bubble columns [28). Glicksman et al [29] provided an excellent review on the development and application of scaling laws for two-phase fluidized beds.…”

Section: Introductionmentioning

confidence: 99%

Similitude Analysis for Gas-Liquid-Fiber Flows in Cocurrent Bubble Columns

Tang

Heindel

2006

Volume 1: Symposia, Parts a and B

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Gas-liquid-fiber systems are different from conventional gas-liquid-solid systems in that the solid material (i.e., fiber) is flexible, has a large aspect ratio, and forms flocs or networks when its mass fraction is above a critical value. With its wide application to the pulp and paper industry, it is important to investigate the hydrodynamics of gas-liquid-fiber systems. In this paper, 19 parameters that influence gas holdup in gasliquid-fiber bubble columns are critically examined and then a dimensional analysis based on the Buckingham Pi Theorem is used to derive the dimensionless parameters governing gas-liquid-fiber bubble column hydrodynamics. Seven dimensionless parameters that are related to the fiber effects on gas holdup are further analyzed, and a single dimensionless parameter combining these dimensionless parameters is derived based on a force analysis and experimental results. This dimensionless parameter is shown to be sufficient to quantify the influence of fiber on gas holdup in gas-liquid-fiber cocurrent bubble columns. It also reduces the number of parameters needed in correlating experimental gas holdup data in gas-liquid-fiber bubble columns. ABSTRACTGas-liquid-fiber systems are different from conventional gas-liquid-solid systems in that the solid material (i.e., fiber) is flexible, has a large aspect ratio, and forms floes or networks when its mass fraction is above a critical value. With its wide application to the pulp and paper industry, it is important to investigate the hydrodynamics of gas-liquid-fiber systems.

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Use of dimensional similitude for scale-up of hydrodynamics in three-phase fluidized beds

Cited by 63 publications

References 0 publications

Gas holdup in a three‐phase fluidized bed

Gas holdup in a three‐phase fluidized bed

Waste Tank Size Determination for the Hanford River Protection Project Cold Test, Training, and Mockup Facility

Similitude Analysis for Gas-Liquid-Fiber Flows in Cocurrent Bubble Columns

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