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Measurement Of Unsteady Flows In Mercury With Hot-Film Anemometers, Charles A. Sleicher, G. B. Lim

Symposia on Turbulence in Liquids

The difficulties in making turbulence measurements in liquid metals are discussed briefly. Attention is then focused on the problem of frequency response attenuation of hot-film anemometers by the thermal capacity of the thermal boundary layer near cylindrical sensors. A solution is given to the problem of heat transfer from an infinite cylinder normal to the potential flow of a fluid with a small sinusoidal velocity component. Application of the results to anemometer measurements is discussed. Some preliminary experiments on dynamic calibration are reported, and they are in reasonable agreement with the theory for Peclet numbers less than one.

Turbulence Measurements In Submerged Water Jets By Electromagnetic Induction Anemometry, Walter C. Mih

Symposia on Turbulence in Liquids

This paper describes the measurement and data analysis of the turbulence in a two-dimensional water jet discharging from a thin slot into a large body of stationary water having the same width as the slot. Tap water without additives was used as the flow medium. The electromagnetic induction method (commonly known as magnetohydrodynamics, or the MHD method) was used to sense the fluctuation velocities in the diffusion zone of the jet. A DC magnet was placed outside the flow field with the magnetic flux density of 885 Gauss perpendicular to the plane of homogeneity of the two-dimensional flow field. A …

Hydrogen-Bubble Flow-Visualization: Limitations In Drag Reducing Polymer Solutions, George L. Donohue

Symposia on Turbulence in Liquids

Hydrogen-bubble flow-visualization experiments have demonstrated that distinct bubble pulses cannot be obtained in water solutions of polyacrylamide of high enough molecular weight to cause drag reduction at low shear stresses. Good bubble pulses were obtained in poly(ethylene oxide) and in surfactant solutions, but they did not cause drag reduction at feasible shear stresses.

Measurement Of Reynolds Stress And Turbulence In Dilute Polymer Solution By Laser Velocimeter, Samuel E. Logan

Symposia on Turbulence in Liquids

Measurements of Reynolds stress and axial and transverse turbulence intensities have been made in turbulent pipe flow of a dilute solution of high molecular weight polymer and compared to measurements made with pure water. A laser velocimeter capable of measuring these turbulence parameters has been developed and utilized.

Axial turbulence intensities are consistent in behavior and magnitude with previous polymer results and the measurements of transverse intensity and Reynolds stress are similarly well behaved and self consistent. Sublayer thickening in drag reducing polymer solution is observed, in consonance with earlier work. New results include demonstration that the turbulent shearing stress …

Conference Proceedings Of The 3rd Biennial Symposium On Turbulence In Liquids, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

The Third Biennial Symposium on Turbulence in Liquids showed further progress in the investigator's ability to measure turbulence parameters and in the general understanding of turbulence. The most impressive advances in measurement seemed to be the ability to measure deeper into the turbulent boundary layer in order to obtain profiles over the entire turbulence production region and the rapid development of conditioned-sampling techniques for studying hypotheses for mechanisms.

Ldv Measurements In Turbulent Free Convection, R. J. Adrian

Symposia on Turbulence in Liquids

The design and performance of a laser Doppler velocimeter (LDV) used in a turbulent water-overice convection experiment are described. The LDV was operated in a reference beam mode with an ultrasonic diffraction grating shifting the reference beam frequency to provide bipolar sensing of the vertical velocity, and a phase-locked loop was used to demodulate the Doppler frequency information. The maximum observed velocities in the experiment were ± 1 mm/sec, and the accuracy of instantaneous measurement was limited by Brownian motion and laser line width to ± .04 mm/sec for a 2 Hz frequency response. The practical difficulties encountered in this …

Features Of A Separating Turbulent Boundary Layer As Revealed By Laser And Hot-Film Anemometry, R. L. Simpson, J. H. Strickland, P. W. Barr

Symposia on Turbulence in Liquids

Experiments have been performed to determine the fundamental nature of boundary layer separation produced by an adverse pressure gradient. Measurements upstream and downstream of the separation zone have been made utilizing laser and hot-film anemometry techniques.

A completely mobile backscattering laser anemometer was developed. This alone is a significant development because of the relatively long focal lengths required for measurements in a 36" wide wind tunnel. Signal processing was achieved by a digital signal sampling and storage system. Both mean and fluctuating velocities in both the unseparated and separated flow regions were measured. Experimental results are in fairly good agreement …

Turbulence Measurements With A Sampling Laser-Doppler Velocimeter, P. D. Iten

Symposia on Turbulence in Liquids

A novel sampling signal processor overcomes the difficulties encountered with frequency trackers in the investigation of unseeded highly turbulent flows. This sampling system consists essentially of a swept filter, e.g. a standard RF-spectrum analyzer, a digital data memory and a storage oscilloscope. It is able to determine first-order statistical averages of turbulent flows with high fluctuation frequencies and amplitudes even at very low scattering particle concentrations. Since the velocity samples are not statistically independent of the velocity, the sampled velocity data has to be corrected in order to obtain unbiased statistical averages. A theoretical analysis and experimental investigations of the …

Analysis Of A Laser Correlation Anemometer, L. Lading

Symposia on Turbulence in Liquids

An analysis of a laser anemometer is given. The anemometer is based on the cross correlation of the random signals generated by the scattering from -- and/or extinction of -- two parallel laser beams. The basic set-up is compared with the laser Doppler anemometer.

It is shown that the correlation function exhibits a broadening and generally also a skewness - equivalent to the broadening (transit time) and skewness (velocity gradients) of the Doppler spectrum.

The conditions for "instantaneous point" measurements are derived.

It is shown how a particle (drop/bubble) size versus particle velocity spectrum can be obtained by appropriate electronic …

Design Considerations For A Laser Doppler Velocimeter, Leroy M. Fingerson

Symposia on Turbulence in Liquids

In optimizing an instrument design, it is important to differentiate between the theoretical limitations of the technique and apparent limitations that can be reduced or eliminated by design. In the laser-Doppler anemometer, the theoretical limits are associated with the fact that particle velocity is the measurement rather than fluid velocity. The accuracy and speed of the particle velocity measurements do not appear to have theoretical limitations. Therefore, instrument design must concentrate on improving the measurement of particle velocity.

A complete system has been designed to optimize accuracy, speed, convenience, and flexibility in measuring particle velocity. The problems inherent in transferring …

Optimization Of An Lda System, Robert Smid

Symposia on Turbulence in Liquids

This paper discusses the various considerations leading to the optimization of a laser Doppler anemometer for measurements in the flows of gases, liquids, and solids. The requirements placed on the various parameters of the optics by the experiment are discussed in general for different modes of operation. Expressions determining these optical parameters in certain instances given by various authorities are presented and compared. This includes such topics as: laser power, particle size, measuring volume size, optical variation in transmitting and receiving optics, and photodetector selection.

Phase Separation In Turbulent Two-Phase Flow, Francois J. Resch, Hans J. Leutheusser

Symposia on Turbulence in Liquids

The paper is based on an experimental study of a typical instance of bubbly two-phase flow, viz. the air-entraining roller zone of hydraulic jumps in open channels. The investigation was undertaken with the aid of hot-film anemometry techniques involving instant digitization of analog signals, and delayed electronic processing of the tape-recorded data. Special computer programs were designed to separate the two phases according to a well-defined signal threshold. It is this aspect of the work which is being dealt with in the paper.

Turbulent Characteristics Of Two-Phase, Gas-Liquid Stratified Channel Flow, D. M. Johns, T. G. Theofanous, R. N. Houze

Symposia on Turbulence in Liquids

The turbulence characteristics of the bulk phases were studied in a stratified, two-dimensional, gas- liquid channel flow. Initial results are presented comparing mean velocity and turbulent intensity profiles with those obtained in a prior study at the same bulk phase Reynolds numbers. The results indicate that comparison of two realizations of stratified gas- liquid flow cannot be adequately done on the basis of bulk-phase Reynolds numbers. Comparisons must be based on some more fundamental relationships involving the gas-liquid interactions.

Experimental Measurement Of Particle Dispersion In Turbulent Flow, N. M. Howard, C. C. Meek, B. G. Jones

Symposia on Turbulence in Liquids

The dispersion of particles in turbulent flows, phenomena such as dispersion, diffusion, and sedimentation, and a more fundamental point of view, the description of particle interaction with the turbulent field are recently of increasing interest. A system capable of investigating statistical structure of the motion of particles in a turbulent fluid flow using a turbulent water pipe flow system and particles tagged with C0-60 radioactive pellets has been constructed and tested. The particles were followed in their trajectory by a group of detectors consisting of NaI(Tℓ) crystals mounted on photomultiplier tubes which move with the particles on a movable carriage. …

Conditioned Sampling Techniques, R. E. Kaplan

Symposia on Turbulence in Liquids

The concept of organized, spatially coherent large scale structures has been investigated for a variety of turbulent shear flows by a technique called "Conditional Sampling." It can be shown that these structures are related to physically important activities such as, 1) the entrainment of turbulent boundary layers, and 2) the maintenance of turbulence by a wall, 3) the growth of free shear layers, and 4) the structure and noise production of turbulent jets.

The general technique of conditioned sampling is related to visualizations of the flow, and to problems of synchronization of images in the presence of noise. While there …

A Comparison And Analysis Of Detection Methods For The Measurement Of Production In A Boundary Layer, G. R. Offen, S. J. Kline

Symposia on Turbulence in Liquids

Two hot films and dye visualizations have been employed, simultaneously, in a turbulent boundary layer to explore the relations among visual observations and five kinds of detection methods using conditional sampling. The results show that all methods correlate positively with each other, but not with high enough values of correlation coefficients to indicate true correspondence between any two thus far studied. Moreover, none of the detection methods devised to date indicate a plateau in number of events as a function of trigger threshold.

The results also provide additional information on several other matters: (i) the relationship of outward motions from …

On The Interpretation Of The Output Of Hot-Film Anemometers And A Scheme Of Dynamic Compensation For Water Temperature Variation, J. Tan-Atichat, H. M. Nagib, J. W. Pluister

Symposia on Turbulence in Liquids

Using a special calibration tunnel developed during the course of this study, the static and dynamic response of several kinds of commercially available hot-film probes with single and multiple sensors of the cylindrical-fiber type are examined. The effects of different parameters, including those of the anemometer bridge, on the output and performance of the probes are evaluated. In particular, the consequences of variations in water temperature on the hot-film anemometer output are determined. The results reveal a large effect of the water temperature on the calibration curves (in an extreme case a change in temperature of only 5.5°F can result …

An Experimental And Theoretical Study Of The Viscous Sublayer For Turbulent Tube Flow, Lindon C. Thomas, H. L. Greene

Symposia on Turbulence in Liquids

Flush-mounted anemometer probes have been used to further study characteristics of the viscous sublayer for both Newtonian and drag reducing solutions, with particular emphasis given to low Reynolds number turbulent tube flow. Experimental measurements for the mean frequency of bursting or renewal within the wall region are compared with theoretical predictions obtained on the basis of the surface renewal and penetration model.

Both theory and experiment taken together suggest that the effect of the mean axial pressure gradient on the viscous sublayer becomes important for the deeper molecular penetration associated with low Reynolds number flow. Also, a pronounced lessening of …

Convergence Of Material Balance In Mathematical Simulation Of Petroleum Reservoirs, Abdul Rashid Merchant

Doctoral Dissertations

One criterion for determining the precision of pressures calculated by a simulation model is the accuracy of the material balance. A high degree of precision in the calculated pressures is a necessary condition for elimination of error in prediction of fluid migration in the reservoir. However, this condition is not sufficient to guarantee accuracy of the simulation, since inaccuracies are introduced by truncation errors, machine round-off errors, and by the use of finite difference approximations to represent nonlinear partial differential equations.

A new procedure called Error Matrix Technique has been developed for reduction of material balance errors. This reduction is …

Film Boiling Of Freon 113, Normal Pentane, Cyclopentane, And Benzene From Cylindrical Surfaces At Moderate Pressures, Gary Joseph Capone

Doctoral Dissertations

"An investigation of film boiling heat transfer in saturated pools of liquid Freon 113, Normal Pentane, Cyclopentane, and Benzene was made. The fluids were boiled from copper, cylindrical heat transfer surfaces, 3 inches long, and 0.55, 0.75, and 1.00 inch in diameter. The heat transfer elements were positioned horizontally in an autoclave and tested at moderate pressures of up to a pressure of 242.5 psia for Normal Pentane.

The experimental data are discussed and compared with known film boiling correlations. The known correlations were found to be inadequate in predicting heat transfer coefficients as a function of pressure, temperature difference …

Film Boiling Of Benzene, Freon 113, Freon 11, And Normal Pentane From Horizontal Surfaces At Atmospheric Pressure, Richard Stanley Kistler

Doctoral Dissertations

"A film boiling study was conducted with five different area flat plates at atmospheric pressure for benzene, Freon 113, Freon 11, and n-pentane. The heat transfer surface was horizontal for all tests.

The data were compared to the correlations commonly used for heat transfer. The common correlations were found to be in error for small surface sizes, but adequate for all fluids except benzene for the largest surface, a semi-empirical equation which correlates the available data as a function of surface diameter was derived and discussed"--Abstract, page iii.

Measurement Of Molecular Diffusivities Of Liquid Alkane Systems, James W. Moore

Doctoral Dissertations

"An unsteady-state porous frit method of diffusion coefficient measurement, recently developed in this laboratory, was improved and expanded upon. The experimental technique has been refined and documented. The unsteady-state diffusion of an initially 0.5 N NaCl solution into pure water (effective diffusivity -1.480 x 10^-5 cm²/sec) was employed as the calibration standard. An overall calibration precision of ±4% was obtained. Diffusion times of two hours or less were used for the non-aqueous diffusivity measurements. The validity of this measurement technique was confirmed by the agreement of the measured self-diffusion coefficient of n-heptane (25⁰C) with literature values.

A …

A Quantitative Analysis By Emission Spectroscopy Of The Metallic Constituents Of Biological Samples After Treatment By A Carcinogenic Agent, Charles R. Frydrych

Masters Theses

No abstract provided.

Kinetics And Dynamics Of Continuous Crystallization, Karichangal C. Parthasarathy

Chemical and Biological Engineering ETDs

A design correlation is presented for the prediction of steady state product size distributions resulting from a continuous crystal­lizer, based upon a single experimental determination. This has been accomplished by the definition of a new parameter called the "degree of crystallization," which has been related to the experimental nuclea­tion and growth rates in a salting-out crystallizer. The correlation resulted from the detection of variations in the suspension density of the mother liquor which has previously been assumed constant in cer­tain power law models. The degree of crystallization has also been described in terms of dimensionless number, length and area moments …

A Study Of Homogeneous Catalysis By High-Pressure Kinetics. The Mechanism Of Catalysis Of A Diels—Alder Reaction, Bruce E. Poling, Charles A. Eckert

Chemical and Biochemical Engineering Faculty Research & Creative Works

The application of high-pressure kinetics as a tool to investigate the detailed mechanism of catalysis of a reaction is demonstrated. Activation volumes have been determined for the Diels-Alder addition of 2, 3-dimethylbutadiene to n-butyl acrylate, both uncatalyzed and catalyzed with AICI3. Also, partial molal volumes of reactants and products have been measured. From these data it is shown that the volume profile along the reaction coordinate is similar for both the catalyzed and uncatalyzed reactions. Further, both reactions proceed by a concerted one-step mechanism through a compact transition state with maximum accumulation of double bonds. Thus, the role of the …

The Fate Of Hazardous Polluting Substances In An Aqueous Environment, Robert Paul Casani

Theses

The fate of Hazardous Polluting. Substances (HPS) in an aqueous environment has been investigated using ultraviolet light. Chlorobenzene, o-cresol and nitrobenzene were used as model HPS for this study. The kinetics were followed and good first order plots were obtained for all compounds. The temperature of the reaction was shown to effect the rate. Solid insoluble and soluble non-volatile products were formed in the photolytic reaction of the three model systems.

The Preparation Of Cis- And Trans-1,2-Dimethoxyethylene. The Study Of The Cis-Trans-Rearrangement And Evaluation Of Equilibrium Constants, James T. Waldron

Dissertations

Equilibrium constants for the mercuric acetate-catalyzed reaction, cis-CH₃ OCH=CHOCH₃ D trans-CH₃ OCH=CHOCH₃, have been determined in the liquid and vapor phase over the temperature range 30° - 175°C by gas chromatography analysis. A novel synthesis of the cis- and trans-isomers of 1,2-dimethoxyethylene is discussed. From a screening of 29 catalysts, mercuric acetate, mercuric benzoate, and mercuric salicylate were found to be favorable isomerization catalysts. For the liquid phase reaction,

ln K = -779.8/T + 0.6748

with ΔH° = +1.549 ± 0.019 Kcal/mole
and ΔS° = +1.34 ± 0.05 e.u./mole

Similarly, for the vapor phase reaction, …

The Aging Of Sbr Vulcanizates, Arthur Robert Leckart

Theses

A literature survey was conducted on SBR aging, Being vulnerable to attack by the forces of nature (such as ozone, oxygen, heat and light), SBR vulcanizates requires the addition of chemicals to retard aging. Phenylamines were found to be the best type of antiaging additives, The effectiveness of other antiaging additives were examined. Although the mechanisms of aging are not perfectly understood; sane theories and aging reactions are discussed.

Continuous Crystallization Of High Explosives, Larry E. Hatler

Chemical and Biological Engineering ETDs

Nitroguanidine (NQ) is a high explosive which is commercially available in low bulk density form (0.20 to 0.30 gms/cm³). This low bulk density limits its usefulness as an explosive. High bulk density NQ can be produced from a NQ-N, N-dime-thylformamide-Versamid 125 system when crystallized in a mixed suspension mixed product removal crystallizer. Bulk densities ranged from 0.92 to 1.05 gms/cm³ for the operating conditions used. The effect of agitator speed, growth rate, and solids concentration on nucleation rates was determined using a multiple linear regression technique. The resulting equation is: B₀ = 0.19 (RPM) ^1.54 (G) …

Dispersion In Laminiar Flow Of Non-Newtonian Fluids, Subhash N. Shah

Chemical and Biological Engineering ETDs

In the present investigation, Taylor's analysis of the dispersion of solutes in laminar flow of a Newtonian fluid through a circular tube was extended to the case of a non-Newtonian Eyring model fluid. A new approach was taken to solve the convective diffusion equation for the Eyring model fluid. This approach incorporates the use of the dimensionless longitudinal pressure gradient and the mean velocity to obtain the dimensionless concentration. Using an approach similar to that of Taylor, a solution of the diffusion equation was obtained for quantities such as the dimensionless concentration, mean concentration, and effective dispersion coefficient as a …