A Statistical Intelligence (STI) Approach to Discovering Spurious Correlation in a Physical Model and Resolving the Problem With an Example of Designing a Pulse Jet Mixing System at Hanford

Pulse jet mixing tests were conducted to support the design of mixing systems for the Hanford Waste Treatment and Immobilization Plant. A physical approach (based on hydro-dynamic behavior) and two semi-empirical (SE) approaches were applied to the data to develop models for predicting two response variables (critical-suspension velocity and cloud height). Tests were conducted at three geometric scales using multiple noncohesive simulants and levels of possibly influential factors. The physical modeling approach based on hydrodynamic behavior was first attempted, but this approach can yield models with spurious correlation. To overcome this dilemma, two semi-empirical (SE) models were developed by generalizing the form of the physical model using dimensional and/or nondimensional (ND) variables. The results of applying statistical intelligence (STI) tools to resolve the spurious correlation problem via fitting the physical and SE models are presented and compared. Considering goodness-of-fit, prediction performance, spurious correlation, and the need to extrapolate, the SE models based on ND variables are recommended.

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Solids Erosion Patterns Developed by Pulse Jet Mixers

Volume 1B, Symposia: Fluid Measurement and Instrumentation; Fluid Dynamics of Wind Energy; Renewable and Sustainable Energy Conversion; Energy and Process Engineering; Microfluidics and Nanofluidics; Development and Applications in Computational Fluid Dynamics; DNS/LES and Hybrid RANS/LES Methods ◽

10.1115/fedsm2017-69382 ◽

2017 ◽

Author(s):

Judith Ann Bamberger ◽

Leonard F. Pease ◽

Michael J. Minette

Keyword(s):

Process Parameters ◽

Waste Treatment ◽

Measurement Techniques ◽

Applied Pressure ◽

Initial Step ◽

Pulse Tube ◽

Jet Mixing ◽

Under Construction ◽

Pulse Jet ◽

Pulse Jet Mixing

Millions of gallons of radioactive waste are stored in underground tanks at the Hanford Site in Washington State. This waste will be vitrified at the Waste Treatment and Immobilization Plant that is under construction. Vessels in the pretreatment portion of the plant are being configured for processing waste slurries with challenging physical and rheological properties that range from Newtonian slurries to non-Newtonian sludge. Pulse jet mixing (PJM) technology has been selected for mobilizing and mixing this waste. In the pulse jet mixing process, slurry is expelled from pulse tube nozzles directed towards the vessel floor. The expelled fluid forms a radial jet that erodes the settled layer of solids. The pulse tubes are configured in a ring or multiple rings and operate concurrently. The expelled fluid and mobilized solids traverse toward the center of the tank. At the tank center, the jets from pulse tubes in the ring collide and lift solids upward in a central plume. At the end of the pulse, when the desired fluid volume has been expelled from the pulse tube, the applied pressure switches to suction and the pulse tubes are refilled. This cycle is used to mobilize and mix the tank contents. An initial step of the process is the erosion of solids from the vessel floor by the radial jets that form on the vessel floor beneath each pulse tube. Experiments have been conducted using simulants to evaluate the ability of the pulse jet mixing system radial jets to combine to develop the central upwell and lift solids in the vessel. These experiments were conducted at three scales using a range of granular simulants over a range of concentrations in vessels with elliptical, spherical, or flanged and dished bottoms. Process parameters evaluated experimentally include the velocity of fluid expelled from the pulse tube, the duration of the pulse and the ratio of pulse duration to cycle time. Videos taken from beneath the vessel show the growth of the cleared area beneath each pulse tube as a function of time during the pulse. The focus of this paper is to describe measurement techniques and compare and contrast erosion patterns developed from different simulants and pulse tube configurations. The cases are evaluated to determine how changes in process parameters affect the PJM’s ability to mobilize solids from the vessel floor.

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Scaled Experiments Evaluating Pulse Jet Mixing of Slurries

Volume 9: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A, B and C ◽

10.1115/imece2009-12264 ◽

2009 ◽

Author(s):

Judith Ann Bamberger ◽

Perry A. Meyer ◽

Carl W. Enderlin ◽

James A. Fort ◽

Beric E. Wells ◽

...

Keyword(s):

Flow Condition ◽

Large Scale ◽

Waste Treatment ◽

Jet Mixing ◽

Cloud Height ◽

Steady Flow Condition ◽

Two Parameters ◽

Minimum Velocity ◽

Pulse Jet ◽

Pulse Jet Mixing

Pulse jet mixing (PJM) tests with noncohesive solids in Newtonian liquid were conducted at three geometric scales to support the design of mixing systems for the Hanford Waste Treatment and Immobilization Plant. The test data will be used to develop mixing models. The models predict the cloud height (the height to which solids will be lifted by the PJM action) and the critical suspension velocity (the minimum velocity needed to ensure all solids have been lifted from the floor), two parameters measured during the tests. From the cloud height estimate, the concentration of solids near the vessel floor and the minimum velocity predicted to lift solids can be calculated. The test objective was to observe the influence of vertically downward-directed jets on noncohesive solids in a series of scaled tanks with several bottom shapes. The test tanks and bottom shapes included small- and large-scale tanks with elliptical bottoms, a mid-scale tank with a spherical bottom, and a large-scale tank with a flanged and dished bottom. During testing, the downward-directed jets were operated in either a steady flow condition or a pulsed (periodic) flow condition. The mobilization of the solids resulting from the jets was evaluated based on: the motion/agitation of the particulate on the tank floor and the elevation the solids reach within the tank; the height the solids material reaches in the tank is referred to as the cloud height (HC).

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Evaluating Pulse Jet Mixing With Non-Newtonian Slurries

Volume 8: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A and B ◽

10.1115/imece2007-42223 ◽

2007 ◽

Author(s):

Judith Ann Bamberger ◽

Perry A. Meyer ◽

Jagan R. Bontha ◽

James A. Fort ◽

Franz Nigl ◽

...

Keyword(s):

Waste Treatment ◽

Treatment Plant ◽

Newtonian Fluids ◽

Jet Mixing ◽

Waste Treatment Plant ◽

Pulse Jet ◽

Pulse Jet Mixing

Pulse jet mixer technology has been selected for implementation in the Hanford Waste Treatment Plant. However, processing non-Newtonian fluids using this technology is not mature. Experiments were conducted at several scales to develop an understanding of the scaling mechanisms that govern this type of mixer performance.

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Pulse Jet Mixing Tests With Noncohesive Solids

10.2172/1036077 ◽

2012 ◽

Cited By ~ 1

Author(s):

Perry A. Meyer ◽

Judith A. Bamberger ◽

Carl W. Enderlin ◽

James A. Fort ◽

Beric E. Wells ◽

...

Keyword(s):

Jet Mixing ◽

Pulse Jet ◽

Pulse Jet Mixing

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Concentration Distribution During Pulse Jet Mixing

ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting: Volume 2, Fora ◽

10.1115/fedsm-icnmm2010-31314 ◽

2010 ◽

Author(s):

Judith Ann Bamberger ◽

Perry A. Meyer

Keyword(s):

Real Time ◽

Ultrasonic Attenuation ◽

Concentration Data ◽

Jet Mixing ◽

Slurry Concentration ◽

Suspension Process ◽

Solids Suspension ◽

Pulse Jet ◽

Pulse Jet Mixing

Obtaining real-time, in situ slurry concentration measurements during unsteady mixing can provide increased understanding into mixer performance. During recent tests an ultrasonic attenuation sensor was inserted into a mixing vessel to measure the slurry concentration during unsteady mixing in real time during pulse jet mixer operation. These pulse jet mixing tests to suspend noncohesive solids in Newtonian liquid were conducted at three geometric scales. To understand the solids suspension process and resulting solids distribution, the concentration of solids in the cloud was measured at various elevations and radial positions during the pulse jet mixer cycle. In the largest scale vessel, concentration profiles were measured at three radial locations: r = 0, 0.5 and 0.9 R where R is the vessel radius. These radial concentration data are being analyzed to provide a model for predicting concentration as a function of elevation. This paper describes pulse jet mixer operation, provides a description of the concentration probe, and presents transient concentration data obtained at three radial positions: in the vessel center (O R), midway between the center and the wall (0.5 R) and near the vessel wall (0.9 R) through out the pulse to provide insight into pulse jet mixer performance.

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Characterizing Pulsating Mixing of Slurries

Volume 2: Fora, Parts A and B ◽

10.1115/fedsm2007-37666 ◽

2007 ◽

Author(s):

Judith Ann Bamberger ◽

Perry A. Meyer

Keyword(s):

Reynolds Number ◽

Settling Velocity ◽

Velocity Ratio ◽

Applied Pressure ◽

Pulse Tube ◽

Operational Parameters ◽

Hindered Settling ◽

Jet Mixing ◽

Pulse Jet ◽

Pulse Jet Mixing

This paper describes the physical properties for defining the operation of a pulse jet mixing system. Pulse jet mixing systems operate with no moving parts located in the vessel or in the fluid to be mixed. Pulse tubes submerged in the vessel provide a pulsating flow that mixes the fluid due to a controlled combination of applied pressure to expel the fluid from the pulse tube nozzle followed by suction to refill the pulse tube through the same nozzle. For mixing slurries nondimensional parameters to define mixing operation include slurry properties, geometric properties and operational parameters. Primary parameters include jet Reynolds number and Froude number; alternate parameters may include particle Galileo number, particle Reynolds number, settling velocity ratio, and hindered settling velocity ratio. Rating metrics for system performance include just suspended velocity, concentration distribution as a function of elevation, and blend time.

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Cyclic Concentration Measurements for Characterizing Pulsating Flow

Volume 2, Fora: Cavitation and Multiphase Flow; Fluid Measurements and Instrumentation; Microfluidics; Multiphase Flows: Work in Progress ◽

10.1115/fedsm2013-16458 ◽

2013 ◽

Author(s):

Judith Ann Bamberger

Keyword(s):

Concentration Profile ◽

Pulsating Flow ◽

Local Concentration ◽

Concentration Data ◽

Jet Mixing ◽

Periodic Pulse ◽

Solids Concentration ◽

Concentration Measurements ◽

Pulse Jet ◽

Pulse Jet Mixing

Slurry mixed in vessels via pulse jet mixers has a periodic, rather than steady, concentration profile. Measurements of local concentration taken at the center of the tank at a range of elevations within the mixed region were analyzed to obtain a greater understanding of how the periodic pulse jet mixing cycle affects the local concentration. Data were obtained at the critical suspension velocity, when all solids are suspended at the end of the pulse. The data at a range of solids loadings are analyzed to observe the effect of solids concentration during the suspension and settling portions of the mixing cycle.

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Multiphase Flow Concentration Characterization in Slurries During Pulse Jet Mixing

Volume 2: Fora ◽

10.1115/fedsm2012-72466 ◽

2012 ◽

Author(s):

Judith Ann Bamberger

Keyword(s):

Real Time ◽

Ultrasonic Attenuation ◽

Concentration Data ◽

Jet Mixing ◽

Slurry Concentration ◽

Suspension Process ◽

Solids Suspension ◽

Pulse Jet ◽

Pulse Jet Mixing

Obtaining real-time, in situ slurry concentration measurements during unsteady mixing can provide increased understanding into mixer performance. During tests of an operating pulse jet mixing system, an ultrasonic attenuation sensor was inserted into a mixing vessel to measure the slurry concentration during unsteady mixing in real time. Pulse jet mixing tests to suspend noncohesive solids in Newtonian liquid were conducted at three geometric scales. To understand the solids suspension process and resulting solids distribution, the concentration of solids in the cloud was measured at various elevations and radial positions during the pulse jet mixer cycle. This paper presents transient concentration data obtained at three scales at the tank center to provide insight into pulse jet mixer performance.

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