Cyclic Concentration Measurements for Characterizing Pulsating Flow

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.

In Situ Measurement Techniques for Characterizing Pulse Jet Mixing of Slurries

2009 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Margaret S. Greenwood ◽  
Gerald W. Morgan ◽  
Perry A. Meyet ◽  
Ellen B. K. Baer ◽  
...  
Keyword(s):  
Concentration Profile ◽  
Ultrasonic Attenuation ◽  
Measurement Techniques ◽  
Jet Mixing ◽  
Cloud Height ◽  
Solids Concentration ◽  
Relative Measurements ◽  
Ultrasonic Doppler Velocimetry ◽  
Pulse Jet ◽  
Pulse Jet Mixing

Metrics to characterize mixing are the just suspended velocity (UJS) and the cloud height (HC). Two ultrasonic instruments to characterize pulse jet mixing of slurries were developed and deployed to measure related metrics: the thickness of the settled bed and the concentration within the cloud as a function of elevation [C(Z)]. Ultrasonic Doppler velocimetry was used to measure the thickness of the bed of nonmoving particles (the settled solids layer). During pulse jet mixing at the critical suspension velocity (UCS) the settled solids layer thickness approached zero at the end of the jet pulse. The UCS is related to the just suspended velocity (UJS) for steady mixing. Ultrasonic attenuation was used to measure the suspended solids concentration at locations in the vessel to determine the concentration profile as a function of radial position and elevation. The concentration profile provided data inside the particulate cloud and complemented the visual measurement of the cloud height (HC). The UDV and the ultrasonic concentration probe data are used to evaluate the desired metrics based on relative measurements. The relative measurements are correlated with results obtained from a series of working standards created for each slurry, and used to develop correlations specific to each slurry.

Concentration Distribution During Pulse Jet Mixing

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.

Multiphase Flow Concentration Characterization in Slurries During Pulse Jet Mixing

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.

scholarly journals Pulse Jet Mixing Tests With Noncohesive Solids

2012 ◽  
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

Characterizing Pulsating Mixing of Slurries

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.

Solids Erosion Patterns Developed by Pulse Jet Mixers

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.

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

2010 ◽  
Author(s):  
Brett G. Amidan ◽  
Greg F. Piepel ◽  
Alejandro Heredia-Langner ◽  
Perry A. Meyer ◽  
Beric E. Wells ◽  
...  
Keyword(s):  
Physical Model ◽  
Goodness Of Fit ◽  
Waste Treatment ◽  
Influential Factors ◽  
Jet Mixing ◽  
Spurious Correlation ◽  
Correlation Problem ◽  
Semi Empirical ◽  
Pulse Jet ◽  
Pulse Jet Mixing

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.

scholarly journals Pulse Jet Mixing Tests With Noncohesive Solids

2009 ◽  
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

Evaluating Concentration Profiles During Unsteady Mixing

2009 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Margaret S. Greenwood ◽  
Bruce D. Lawler ◽  
S. K. Sundaram ◽  
Ellen B. K. Baer ◽  
...  
Keyword(s):  
Newtonian Liquid ◽  
Concentration Profiles ◽  
Jet Mixing ◽  
Suspension Process ◽  
Solids Suspension ◽  
Pulse Jet ◽  
Pulse Jet Mixing

Pulse jet mixing tests to suspend noncohesive solids in Newtonian liquid were conducted at three geometric scales. To understand the solids suspension process an ultrasonic concentration probe was used to measure the concentration of solids in the cloud during a pulse at various elevations and radial positions. The data are being analyzed to provide a model for predicting concentration as a function of elevation.

Sign in / Sign up

Export Citation Format

Share Document