Chemical Engineering Commons^™

Hot-Film Anemometry In Air-Water Flow, J. M. Delhaye, J. P. Galaup

Symposia on Turbulence in Liquids

The paper presents local measurements of void fraction and liquid velocity in a steady-state air- water bubbly flow at atmospheric pressure. Use is made of a constant temperature anemometer and of a conical hot-film probe.

The signal is processed with a multi-channel analyzer. Void fraction and liquid velocities are determined from the amplitude histogram of the signal.

The integrated void fraction over a diameter is compared with the average void fraction along the same diameter obtained with a γ-ray absorption method.

The liquid volumetric flow-rate is calculated from the void fraction and liquid velocity profiles and compared with the indication …

Measurement Of Both Gas And Particle Velocity In Turbulent Two-Phase Flow, D. E. Stock, J. T. Jurewicz, C. T. Crowe, J. E. Eschbach

Symposia on Turbulence in Liquids

A laser-Doppler anemometer was used to measure the velocity of both the gas and particles in a turbulent two-phase flow for conditions when the distribution of the velocities of the two phases overlaps. The velocities from the two phases are separated by comparing the Doppler amplitude to the pedestal amplitude. Results of the measure of the gas-particle flow downstream of a nozzle mounted in a circular pipe are presented.

Liquid Turbulence And Its Measurement, R. L. Humphrey

Symposia on Turbulence in Liquids

This paper covers several principles which have been successfully developed over the past few years and used in the measurement of liquid flows. In particular, ultrasonics, electro-magnetics, thermal heat transfer and optical light transmission will be discussed. Each concept will be covered by basic definitions and laws, theory of operation and application where measurement parameters will be highlighted, thus allowing the user to choose the best instrument to fit his experimental needs.

Red Blood Cells And Turbulence, E. F. Blick, H. N. Sabban, P. D. Stein

Symposia on Turbulence in Liquids

Measurements were made of the turbulence intensity of blood of various hematocrits (volume percentage of red cells in blood) flowing through an orifice. The maximum relative turbulence intensity was found to occur in the hematocrit range of 20% - 30%.

Characteristics Of Laser Anemometer Signals And Frequency Demodulators For Highly Seeded Flows, R. V. Edwards

Symposia on Turbulence in Liquids

An analysis of the general characteristics of laser anemometer signals for liquid flows is made. Three detection schemes are analyzed:
(1) Spectral analysis of the photodetector output,
(2) frequency trackers, and
(3) counters
Where known, the strengths and weakness of each method are analyzed.

Measurement Of Turbulence Power Spectra In Agitated Vessels Of Different Size With A Laser-Doppler Velocimeter, K. Van Der Molen, H. R. E Van Maanen

Symposia on Turbulence in Liquids

We have used the laser-Doppler velocimeter with a new noise reduction technique for measurements in water-filled, turbine-agitated vessels of several sizes, but of the same geometry. Mean velocities, turbulence intensities and turbulence power spectra were obtained in the impeller stream region.

With these results we hope, in the future, to put scaling rules for mixing vessels on a sounder basis.

Spatial Filtering In Laser Anemometry, L. Lading

Symposia on Turbulence in Liquids

The concept of spatial filtering is treated in relation to laser anemometry. The basic techniques are analyzed. Recommendations for specific set-ups are given.

Turbulence Effects Upon Laser Propagation In The Marine Boundary Layer, K. L. Davidson, T. M. Houlihan

Symposia on Turbulence in Liquids

Shipboard measurements of small scale temperature and velocity fluctuations have been accomplished to determine optical wave propagation properties of the marine boundary layer. Measurements were recorded for ocean conditions in Monterey Bay and in the confines of the Pacific Missile Range. Laser beam propagation measurements were performed in conjunction with the meteorological measurements.

Session Chairman Introductory Remarks, R. J. Hansen

Symposia on Turbulence in Liquids

No abstract provided.

Periodic And Random Excitation Of Streamlined Structures By Trailing Edge Flows, W. K. Blake

Symposia on Turbulence in Liquids

This paper is an examination of semi-empirical techniques which are shown to be effective in predicting the response of hydrofoils to flow excitation. Examples are given for buffeting by inflow turbulence, excitation by the boundary-layer pressures on the hydrofoil, and linear and non-linear excitation by vortex street formation in the wake. Co-ordinated aerodynamic and hydrodynamic measurements are used in Reynolds number - scaled experiments to determine both the flow induced forces and the hydro-elastic behavior on cantilever struts. An analytical formulation based on normal mode theory is used to combine the results.

An Investigation Of The Criteria Controlling Sustained Self-Excited Oscillations Of Cylinders In Flowing Water, R. King

Symposia on Turbulence in Liquids

In this paper, water channel experimental data are discussed and compared with conventional wind-tunnel data. Stability criteria are proposed for the cross-flow and flow directions of oscillation. Fluctuating drag force coefficients are deduced from a linear mathematical representation of the cylinder located in flowing water and oscillating in the flow direction.

Local Mass Transfer In Turbulent Flow By Electrochemical Methods, C. Deslouis, I. Epelboin, B. Tribollet, L. Viet

Symposia on Turbulence in Liquids

Mass transfer to the surface of rotating electrodes during turbulent flow was studied by electrochemical methods under steady and non-steady state diffusion conditions.

The flow was due to a large rotating disk made from insulating material, flush with the surface of which was mounted a ring shaped electrode of platinum or nickel.

A local study of the radial component of the convective diffusion in turbulent flow was carried out with very thin ring electrodes (width ΔR ~ 0,05 mm). The diffusion layer thickness was varied relatively to the diffusion sublayer thickness by changing the ring width or the rotation speed …

Experimental Study Of Turbulence In Plane Separated Flows, R. Smyth

Symposia on Turbulence in Liquids

Some recent attempts at predicting turbulent two- dimensional recirculating flows have concentrated on modelling the turbulent energy equations used in the finite difference analysis methods of solutions of the elliptic partial differential equations governing these flows. These attempts have to some extent been restricted by the lack of experimental studies of the high turbulence intensities found in separated flows. The improvement of the pulsed hot-wire anemometer and the laser Doppler anemometer have made possible such studies and this paper describes an investigation using the laser Doppler anemometer in a separated flow situation. Results are given of an experimental study of …

Some Observations Of Wake Behavior In Laminar And Turbulence Free Stream Flow, L. E. Seeley, R. L. Hummel, J. W. Smith

Symposia on Turbulence in Liquids

Visual observations of the sphere wake have been obtained using the flash photolysis technique. Free stream turbulence of 7 and 10% was found to progressively reduce the size of the wake but no turbulence was found in the attached shear layer nor was the position of the separation point affected. A separation bubble was identified as predicted by Son and Hanratty (1969). Evidence is presented to show that drag reduction in turbulent free streams is not due to turbulence in the attached boundary layer but to enhanced momentum transfer in the wake.

The Roles Of Large Scale Structures In The Initial Development Of Circular Jets, F. K. Browand, J. Laufer

Symposia on Turbulence in Liquids

Experimental results are presented describing the flow field surrounding the potential core of a circular water jet in the Reynolds number region between 5,000 and 15,000. This field is divided into three regions: 1) the shear layer instability zone; 2) the vortex interaction region; and 3) the zone of higher order instability mode and turbulence generation. It is shown that the origin of the large scale structures just downstream of the potential cone can be traced to the upstream vortices, but their statistical behaviour (passage frequency, spatial coherence) seems to be independent of the initial shear layer instability.

Stereoscopic Photography Of Shear Flow Turbulence, A. K. Praturi, H. C. Hershey, R. S. Brodkey

Symposia on Turbulence in Liquids

The last several years have seen numerous advances in the understanding of the coherent motions that exist in turbulent shear flows. These studies have provided the underlying basis of most of the experimental investigations of coherent motions using conditional sampling, quadrant splitting, pattern recognition, etc. Lacking, however, in the visual work is a true three- dimensional view of the processes, which are known to be three-dimensional in nature. Possible means of providing information about the third dimension are reviewed. Details of an evaluation of a stereoscopic-photographic, high-speed motion picture system are given. The system utilizes the boundary layer flow channel …

Use Of Sodium Chloride Windows In The Infrared Spectral Analyses Of Irradiated Thin Insoluble Polymer Films, W. F. Oberbeck, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

Creating The Electric Energy Economy, L. G. Hauser

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

My remarks will be directed to four points:

First, that energy is the life blood of our economy, and that its use or conservation is far from a simple matter of personal habits of waste or frugality. In other words, the vital role energy plays in the production of goods and services should be distinguished from its use in their consumption.

Second, that our excessive dependence on our two scarcest energy resources -- oil and natural gas -- is the core of the energy problem, both U.S. and worldwide.

Third, that limiting our time horizon to this winter, next summer, …

Energy And Transportation Policy, James S. Sagner

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

Energy shortages of recent years suggest a re-examination of national transportation policy. The lack of a coordinated approach to the solution of urban cogestion inhibits potential short-run responses to gasoline shortfalls. Longer-range policy, particularly in the context of severe financial constraints, must be carefully integrated with demonstrated patterns of urban travel and population and employment densities. Given these considerations, metropolitan areas now planning or constructing rapid rail facilities may be selecting inappropriate responses to the problem of urban access.

The Design And Performance Of A Distributed Flow Water-Cooled Solar Collector, Donald L. Spencer, Theodore F. Smith, Herbert R. Flindt

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

Design of a flat plate collector which reduces the temperature differential between the absorber plate and the fluid is described. The reduced temperature differences are shown to yield increase collector performance. Flow characteristics of the collector are examined. Collector thermal performance is illustrated for typical operating and environmental conditions. A cost analysis is presented to demonstrate that material and assembly costs are substantially lower than for any collector presently on the market.

How Might Synthetic Fuels From Coal Affect Natural Resources And Environment?, H. J. Plass Jr.

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

Energy self-sufficiency for the U. S. requires substantially increased use of coal. Direct combustion of coal without adequate environmental controls, as would occur if coal were used as a fuel for homes and offices throughout the country, would result in severe air pollution problems„ Synthetic fuels from coal such as methane, low BTU gas, or hydrogen, when utilized by the homes and businesses as gas or as electricity from gas, will contribute a much smaller amount of air pollution. However, to make these synthetic fuels available, it is necessary to mine more coal than would have to be mined for …

Two-Dimensional Analysis Of The Coherent Instationary Motion Induced By An Obstacle, Using Electrochemical Methods, B. Py, C. Tournier

Symposia on Turbulence in Liquids

The non stationary flow induced by a cylinder with a square cross-section was studied on the cylinder's surface and in the wake with two different electrochemical probes. On the cylinder was mounted split rectangular electrodes with high enough aspect ratio so as to measure the chordwise component of the wall shear stress with its sign. The non-linear response of this transducer was studied. In the wake, the longitudinal component of the velocity was obtained with conical electroactive elementswhich are mainly sensitive to this component.

The fluctuating coherent components are separated from the aleatory part of the signal and then decomposited …

Author Index, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

An Experimental Study Of Mass Transfer To Droplets In Aqueous Polymer Solutions., Richard Gerard Schafermeyer

Masters Theses

"Instantaneous and time-average mass transfer coefficients for 1 the free-fall period was obtained for transfer of iodine from nonNewtonian continuous phases to carbon tetrachloride drops. The nonNewtonian continuous phases were aqueous solutions of carboxymethyl cellulose and carboxy polymethylene. Although a few exceptions were found, the continuous phase mass transfer coefficients were, in general, found to decrease with increasing time of drop contact. Comparisons of the experimental data to theoretical relations showed that changes in drop internal circulation probably occurred for that data which showed a time effect for the mass transfer coefficient. Several explanations for the time effect were offered, …

Simulation Of Nonisothermal Absorber-Reactors For Multicomponent Systems, Robert E. Schwab

Doctoral Dissertations

"There are various models available for calculations involving one transferring component with chemical reaction for isothermal conditions using linear equilibrium data. However, the differential equations for multicomponent mass and energy transfer with chemical reaction have not been developed or implemented. This work demonstrates the development of a reliable model describing multicomponent mass and energy transfer in a continuous two-phase absorber-reactor for Non isothermal conditions and demonstrates the feasibility of solving the differential equations numerically. The numerical solution, using nonlinear equilibrium data, is used to obtain the absorber-reactor column specifications"-- Abstract, p. 2

A Computer-Automated Laboratory System In A University Environment, James H. Tracey, Hardy J. Pottinger, Richard D. Rechtien

Electrical and Computer Engineering Faculty Research & Creative Works

A computer-automated laboratory system at the University of Missouri-Rolla, Rolla, which serves a wide variety of instruction and research disciplines including Geophysics, Cloud Physics, and Computer Graphics, is described. The system serves as an example for campuses which are relatively small in geographic area and with budget limitations which dictate a step-by-step evolution. The paper describes 1) the constraints and economics realized in the development of the system, 2) the characteristics of the minicomputer network, and 3) an evaluation of the system philosophy and performance. Also included is a description of diverse laboratory projects supported by the computer-automated system. © …

Conference Proceedings Of The 4th Biennial Symposium On Turbulence In Liquids, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

On The Role Of Conditional Averages In Turbulence Theory, R. J. Adrian

Symposia on Turbulence in Liquids

It is shown that conditional averages in the form of expected values of functions of the velocity at an arbitrary point given the velocities at a finite number of distinct points, appear naturally in certain types of turbulence theories and that the closure problems in such theories ultimately reduce to the approximation of these averages. Two exemplary theories are considered. The first is characteristic of turbulence models formulated in terms of probability density functions whereas the second is related to the derivation of optimal algorithms for the numerical integration of the turbulent Navier-Stokes equations at large Reynolds numbers. Some mathematical …

Mechanical Degradation Of Dilute Solutions Of High Polymers In Capillary Tube Flow, John D. Culter, Jacques L. Zakin, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

Experimental results on mechanical degradation in capillary tubes of polyisobutylene polymers in dilute solution are described. In laminar flow, degradation is independent of tube length, indicating that entrance effects are dominant. This shows that capillary experiments do not yield explicit information on the effect of shear stress on mechanical degradation. In turbulent flow, large entrance effects are also observed, but some degradation does take place in the fully developed flow region. Copyright © 1975 John Wiley & Sons, Inc.

Quantitative Overdesign Of Chemical Processes, R. A. Freeman, J. L. Gaddy

Chemical and Biochemical Engineering Faculty Research & Creative Works

Overdesign is applied to chemical processes to account for expected variations in the design data or design conditions. These variables must be treated quantitatively in order to design a process that is certain to perform adequately. Process dependability is introduced as a means of quantifying variable process behavior. Overdesign using the dependability criterion is a stochastic optimization problem. An example problem with three stochastic variables and two design variables is presented to illustrate these procedures. Copyright © 1975 American Institute of Chemical Engineers