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Laminar mixing of a compressible fluid

Description: From Summary: "A theoretical investigation of the velocity profiles for laminar mixing of a high-velocity stream with a region of fluid at rest has been made assuming that the Prandtl number is unity. A method which involves only quadratures is presented for calculating the velocity profile in the mixing layer for an arbitrary value of the free-stream Mach number. Detailed velocity profiles have been calculated for free-stream Mach numbers of 0, 1, 2, 3, and 5."
Date: February 1949
Creator: Chapman, Dean R.
Partner: UNT Libraries Government Documents Department

On the Stability of the Laminar Mixing Region Between Two Parallel Streams in a Gas

Description: Note presenting a study of the stability of the mixing of two streams both for the interest in the problem and for clarifying certain points in the basic stability theory. Results show that when the relative speed of the two parallel streams exceeds the sum of their velocities of sound, subsonic oscillations cannot occur and the mixing region can be expected to be stable with respect to small disturbances.
Date: January 1953
Creator: Lin, C. C.
Partner: UNT Libraries Government Documents Department

Comparison of Waste Feed Delivery Small Scale Mixing Demonstration Simulant to Hanford Waste

Description: The Hanford double-shell tank (DST) system provides the staging location for waste that will be transferred to the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Specific WTP acceptance criteria for waste feed delivery describe the physical and chemical characteristics of the waste that must be met before the waste is transferred from the DSTs to the WTP. One of the more challenging requirements relates to the sampling and characterization of the undissolved solids (UDS) in a waste feed DST because the waste contains solid particles that settle and their concentration and relative proportion can change during the transfer of the waste in individual batches. A key uncertainty in the waste feed delivery system is the potential variation in UDS transferred in individual batches in comparison to an initial sample used for evaluating the acceptance criteria. To address this uncertainty, a number of small-scale mixing tests have been conducted as part of Washington River Protection Solutions' Small Scale Mixing Demonstration (SSMD) project to determine the performance of the DST mixing and sampling systems. A series of these tests have used a five-part simulant composed of particles of different size and density and designed to be equal or more challenging than AY-102 waste. This five-part simulant, however, has not been compared with the broad range of Hanford waste, and thus there is an additional uncertainty that this simulant may not be as challenging as the most difficult Hanford waste. The purpose of this study is to quantify how the current five-part simulant compares to all of the Hanford sludge waste, and to suggest alternate simulants that could be tested to reduce the uncertainty in applying the current testing results to potentially more challenging wastes.
Date: September 1, 2011
Creator: Wells, Beric E.; Gauglitz, Phillip A. & Rector, David R.
Partner: UNT Libraries Government Documents Department

Investigation of Turbulent Mixing Processes

Description: "With water as driving medium and delivered medium in a device similar to a simple jet apparatus, the pressure and velocity fields of the mixing zone were explored with a pitot bar; the ratio of delivered to driving volume ranged between the values 0, 1, 2, and 4. An attempt was also made to analyze the mixing flow mathematically by integration of the equation of motion, with the aid of conventional formulas for the turbulent shearing stress, but this succeeded only approximately for the very simplified case that a driving jet is introduced in an unlimited parallel flow, while the pressure over the whole mixing field is assumed to be constant. In spite of these dissimilar assumptions for the theory and the experiment, the form of the measured and the computed velocity profiles indicates a very high degree of approximation" (p. 1).
Date: October 1946
Creator: Viktorin, K.
Partner: UNT Libraries Government Documents Department

B physics at the Tevatron Collider

Description: Precision B-physics results from the CDF and DO Collaborations based on data collected during the Tevatron 1992-96 run are presented. In particular we discuss the measurement of B hadron lifetimes, and B{sup 0} - {anti B}{sup 0} mixing results obtained using time- evolution analyses. Perspectives for the next Tevatron run, starting in 1999, are also reported.
Date: May 1, 1997
Creator: De Troconiz, J. F.
Partner: UNT Libraries Government Documents Department

Mixing quality characterization in separations process tanks

Description: An experimental study has been performed on distribution of a dilute immiscible organic liquid dispersed in an aqueous phase contained baffled, paddle-agitated vessel, fitted with cooling coils. Acceptable total liquid levels in the vessel and minimum impeller speed were established for plant scale operation. Axial and radial distributions of the dispersed organic phase as functions of total liquid height, impeller speed, and the number of impellers were examined and some recurring trends were identified. Four stages of dispersion of organic phase in predominantly aqueous phase were identified with increasing rotational speed of impeller(s). The stages were: (1) non-dispersion stage in which the organic layer was undisturbed, (2) the organic layer was decreasing with impeller speed until complete but nonuniform dispersion was attained, (3) the non-uniformity of the completely dispersed mixture decreased with increasing rotational speed of impeller(s), and (4) a grossly uniform dispersion in which the local volume fraction of dispersed phase (organic) in mixture was the same throughout the vessel. Scale-up relations were developed for reproducing a defined mixing quality on two geometrically similar scales of operation, for the attainable condition of complete but non-uniform dispersion. The mixing quality was observed to decrease with increasing liquid depth over acceptable range, but variations in the overall concentration of organic liquid appeared to have only slight effect on the mixing quality.
Date: January 31, 1995
Creator: Hassan, N.M.
Partner: UNT Libraries Government Documents Department

Liquid-Liquid Extraction

Description: Abstract: "Extraction equipment of the multistage mixer-settler type has been found useful for providing the intensive contact between phases that is required in processes involving complex compounds of the heavy metals. In this report, the factors of mixer-settler design and operation are discussed with reference to the known types of mixer-settler units. Following this review, a detailed description is given of mixer-settler units constructed and installed in this laboratory."
Date: May 1953
Creator: Davis, Milton Wickers, (Jr.); Hicks, Thomas E. & Vermeulen, Theodore
Partner: UNT Libraries Government Documents Department

Effects of Parallel-Jet Mixing on Downstream Mach Number and Stagnation Pressure With Application to Engine Testing in Supersonic Tunnels

Description: "A one-dimensional analysis of the results of the parallel-jet mixing encountered in the testing of engines in supersonic wind tunnels is reported. Equations were derived for determining the totla pressure and Mach number behind the tunnel terminal shock. The method represents a simple procedure for determining these quantities while a tunnel is still in the design stage" (p. 1).
Date: March 1953
Creator: Bernstein, Harry
Partner: UNT Libraries Government Documents Department

Theory of the Jet Syphon

Description: Note presenting a new approach to the theory of the mixing of two currents in an injector which deals with an incompressible ideal fluid. The theory shows new potentialities in an appropriate shaping of the form of the walls of the mixing zone so as to improve the jet-syphon efficiency beyond the heretofore theoretically predicted. A few examples of ways to improve jet-syphon efficiency are indicated.
Date: May 1955
Creator: Szczeniowski, B.
Partner: UNT Libraries Government Documents Department

Modeling Bimolecular Reactions and Transport in Porous Media Via Particle Tracking

Description: We use a particle-tracking method to simulate several one-dimensional bimolecular reactive transport experiments. In this numerical method, the reactants are represented by particles: advection and dispersion dominate the flow, and molecular diffusion dictates, in large part, the reactions. The particle/particle reactions are determined by a combination of two probabilities dictated by the physics of transport and energetics of reaction. The first is that reactant particles occupy the same volume over a short time interval. The second is the conditional probability that two collocated particles favorably transform into a reaction. The first probability is a direct physical representation of the degree of mixing in an advancing displacement front, and as such lacks empirical parameters except for the user-defined number of particles. This number can be determined analytically from concentration autocovariance, if this type of data is available. The simulations compare favorably to two physical experiments. In one, the concentration of product, 1,2-naphthoquinoe-4-aminobenzene (NQAB) from reaction between 1,2-naphthoquinone-4-sulfonic acid (NQS) and aniline (AN), was measured at the outflow of a column filled with glass beads at different times. In the other, the concentration distribution of reactants (CuSO_4 and EDTA^{4-}) and products (CuEDTA^{4-}) were quantified by snapshots of transmitted light through a column packed with cryloite sand. The thermodynamic rate coefficient in the latter experiment was 10^7 times greater than the former experiment, making it essentially instantaneous. When compared to the solution of the advection-dispersion-reaction equation (ADRE) with the well-mixed reaction coefficient, the experiments and the particle-tracking simulations showed on the order of 20% to 40% less overall product, which is attributed to poor mixing. The poor mixing also leads to higher product concentrations on the edges of the mixing zones, which the particle model simulates more accurately than the ADRE.
Date: January 1, 2012
Creator: Ding, Dong; Benson, David; Paster, Amir & Bolster, Diogo
Partner: UNT Libraries Government Documents Department

Defining And Characterizing Sample Representativeness For DWPF Melter Feed Samples

Description: Representative sampling is important throughout the Defense Waste Processing Facility (DWPF) process, and the demonstrated success of the DWPF process to achieve glass product quality over the past two decades is a direct result of the quality of information obtained from the process. The objective of this report was to present sampling methods that the Savannah River Site (SRS) used to qualify waste being dispositioned at the DWPF. The goal was to emphasize the methodology, not a list of outcomes from those studies. This methodology includes proven methods for taking representative samples, the use of controlled analytical methods, and data interpretation and reporting that considers the uncertainty of all error sources. Numerous sampling studies were conducted during the development of the DWPF process and still continue to be performed in order to evaluate options for process improvement. Study designs were based on use of statistical tools applicable to the determination of uncertainties associated with the data needs. Successful designs are apt to be repeated, so this report chose only to include prototypic case studies that typify the characteristics of frequently used designs. Case studies have been presented for studying in-tank homogeneity, evaluating the suitability of sampler systems, determining factors that affect mixing and sampling, comparing the final waste glass product chemical composition and durability to that of the glass pour stream sample and other samples from process vessels, and assessing the uniformity of the chemical composition in the waste glass product. Many of these studies efficiently addressed more than one of these areas of concern associated with demonstrating sample representativeness and provide examples of statistical tools in use for DWPF. The time when many of these designs were implemented was in an age when the sampling ideas of Pierre Gy were not as widespread as they are today. Nonetheless, the ...
Date: October 29, 2013
Creator: Shine, E. P. & Poirier, M. R.
Partner: UNT Libraries Government Documents Department


Description: All modeling calculations for the mixing operations of miscible fluids contained in HBLine tanks, JT-71/72, were performed by taking a three-dimensional Computational Fluid Dynamics (CFD) approach. The CFD modeling results were benchmarked against the literature results and the previous SRNL test results to validate the model. Final performance calculations were performed by using the validated model to quantify the mixing time for the HB-Line tanks. The mixing study results for the JT-71/72 tanks show that, for the cases modeled, the mixing time required for blending of the tank contents is no more than 35 minutes, which is well below 2.5 hours of recirculation pump operation. Therefore, the results demonstrate the adequacy of 2.5 hours’ mixing time of the tank contents by one recirculation pump to get well mixed.
Date: November 26, 2013
Creator: Lee, S.
Partner: UNT Libraries Government Documents Department


Description: A wave equation for the pressure in a mixture of water and gas bubbles (such as found in the KEWB Reactor) is derived. The driving force may be either the production of additional bubbles or the growth of existent bubbles. Several illustrative solutions to the wave equation are found. (W.L.H.)
Date: May 25, 1960
Creator: Warner, C.
Partner: UNT Libraries Government Documents Department

Radial Expansion of a Low Energy Positron Beam Passing Through a Cold Electron Plasma within a Uniform Magnetic Field

Description: This paper from the 23rd Conference on Application of Accelerators in Research and Industry conference proceedings studies the radial expansion of a low energy positron beam passing through a cold electron plasma within a uniform magnetic field using a classical trajectory Monte Carlo simulation.
Date: June 18, 2015
Creator: Aguirre, F. F. & Ordonez, Carlos A.
Partner: UNT College of Arts and Sciences

Ammonia at Blodgett Forest, Sierra Nevada, USA

Description: Ammonia is a reactive trace gas that is emitted in large quantities by animal agriculture and other sources in California, which subsequently forms aerosol particulate matter, potentially affecting visibility, climate, and human health. We performed initial measurements of NH{sub 3} at the Blodgett Forest Research Station (BFRS) during a two week study in June, 2006. The site is used for ongoing air quality research and is a relatively low-background site in the foothills of the Sierra Nevada. Measured NH{sub 3} mixing ratios were quite low (< 1 to {approx} 2 ppb), contrasting with typical conditions in many parts of the Central Valley. Eddy covariance measurements showed NH{sub 3} fluxes that scaled with measured NH{sub 3} mixing ratio and calculated aerodynamic deposition velocity, suggesting dry deposition is a significant loss mechanism for atmospheric NH{sub 3} at BFRS. A simple model of NH{sub 3} transport to the site supports the hypothesis that NH{sub 3} is transported from the Valley to BFRS, but deposits on vegetation during the summer. Further work is necessary to determine whether the results obtained in this study can be generalized to other seasons.
Date: November 6, 2007
Creator: Fischer, Marc L. & Littlejohn, David
Partner: UNT Libraries Government Documents Department

Scaling Theory for Pulsed Jet Mixed Vessels, Sparging, and Cyclic Feed Transport Systems for Slurries

Description: This document is a previously unpublished work based on a draft report prepared by Pacific Northwest National Laboratory (PNNL) for the Hanford Waste Treatment and Immobilization Plant (WTP) in 2012. Work on the report stopped when WTP’s approach to testing changed. PNNL is issuing a modified version of the document a year later to preserve and disseminate the valuable technical work that was completed. This document establishes technical bases for evaluating the mixing performance of Waste Treatment Plant (WTP) pretreatment process tanks based on data from less-than-full-scale testing, relative to specified mixing requirements. The technical bases include the fluid mechanics affecting mixing for specified vessel configurations, operating parameters, and simulant properties. They address scaling vessel physical performance, simulant physical performance, and “scaling down” the operating conditions at full scale to define test conditions at reduced scale and “scaling up” the test results at reduced scale to predict the performance at full scale. Essentially, this document addresses the following questions: • Why and how can the mixing behaviors in a smaller vessel represent those in a larger vessel? • What information is needed to address the first question? • How should the information be used to predict mixing performance in WTP? The design of Large Scale Integrated Testing (LSIT) is being addressed in other, complementary documents.
Date: September 27, 2013
Creator: Kuhn, William L.; Rector, David R.; Rassat, Scot D.; Enderlin, Carl W.; Minette, Michael J.; Bamberger, Judith A. et al.
Partner: UNT Libraries Government Documents Department