Chemical Engineering Commons^™

Optimum Control Of Heating, Ventilating And Air Conditioning Systems, Terry R. Weaver

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

The control of HVAC systems has traditionally been performed by relatively simple field hardware. The industry appears, however, to be ready for the use of more sophisticated measures. The paper presents several approaches to the conservation of energy in this area with the use of closed-loop computer control and optimization.

Energy Conservation In Uniroyal, Inc., John C. Madigan

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

In the last year, rapid developments have led to the establishment of industry conservation goals and monitoring by the Department of Commerce and the Federal Energy Administration via the various industry associations.

Since 1972, Uniroyal has progressed more than half way toward the 1980 goal of 15% established for the rubber and chemical industries. This paper will describe details of the program with emphasis on new input, such as the computerized tracking method now in use.

Plant studies have provided an assessment of "base" loads vs. process loads, important when considering unit energy consumption. These vary, particularly with the climate …

Lean Burning Spark-Ignition Engines -- An Overview, J. A. Alic

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

Means of improving the thermal efficiency of spark-ignition internal combustion engines through fuel-lean combustion at part-load are discussed. For purposes of comparison and evaluation, lean-burning engines are classified as modified conventional engines, stratified charge engines, and engines using alternative fuels. Particular attention is given to automobile applications because of their importance for conservation of fuels.

The Chemical Effect Of Ultrasound On Cyanide Solutions, Nabil R. Zaki

Theses

An experimental study was undertaken to investigate the chemical effects of high intensity ultrasonic radiation on cyanide solutions. The effects of aeration, concentration of cyanide and temperatures on the reaction rate are investigated. The experiment was preformed in a 30 mm pyrex tube immersed at a fixed height in a constant volume water bath. Ultrasonic energy was applied through the use of a transducer epoxied at the bottom of the water bath. The power inputs to the transducer were 40W (27KHz) and 100W (21KHz).

At a power of 40W, ultrasound had no chemical effect on cyanide solutions. At 100W, hydrogen …

Non-Isothermal Mercury Pipe Flow Turbulent Characteristics, T. W. Flaherty, L. L. Eyler, A. Sesonske

Symposia on Turbulence in Liquids

The turbulence structure of fully-developed mercury pipe flow, with and without heat transfer, was studied using hot-film anemometry at Reynolds number of approximately 50,000. Single sensors and slanted multiple sensors were used to obtain the radial distribution of axial fluctuating velocity and temperature quantities. Isothermal data were generally in good agreement with comparable air data indicating similar velocity structure. Temperature intensity data agreed with other data in liquid metals.

Axial and radial turbulent heat flux results were somewhat inconclusive. Spectra and turbulence scales were developed providing a picture of the structure.

Measurement Of The Low-Wavenumber Component Of Turbulent Boundary Layer Pressure Spectral Density, P. W. Jameson

Symposia on Turbulence in Liquids

This paper describes an experiment in which the turbulent boundary layer (TBL) over a flat plate excites bending waves in that plate predominantly through low-wavenumber components in the pressure field having the same wavenumber as the bending waves of the plate. The plate design is such that contributions to the bending waves from the convective peak of the TBL pressure and from acoustic noise are minimal. The level of response of individual modes of the plate is used to measure the intensity of these low-wavenumber spectral components in the TBL wall pressure.

Flow Visualization Studies Of Check Valve Vibrations, D. S. Weaver, F. A. Adubi

Symposia on Turbulence in Liquids

A swing-type hydraulic check valve was found to vibrate continuously when a damper was applied to prevent slamming. A research program was conducted to develop an understanding of the phenomenon and thereby determine a method of alleviation. This paper describes the flow phenomena observed during flow visualization studies of a two dimensional full scale model of the valve. Such observations give insight into the mechanism of vibration.

Session Chairman Introductory Remarks, T. J. Hanratty

Symposia on Turbulence in Liquids

No abstract provided.

Separation Of Low Reynolds Number Flows Around A Corner, T. Matsui, M. Hiramatsu, M. Hanaki

Symposia on Turbulence in Liquids

It was shown experimentally that low Reynolds number flows around a sharp corner do not separate at the corner, and separation points move downstream from the corner with decrease in Reynolds number. For the flow in a channel with a backward-facing step, the experimental results showed a good agreement with those of numerical calculation for the position of separation points and the length of standing vortices.

The Separation Angle For Spheres In A Pipeline, B. Latto, A. Lai

Symposia on Turbulence in Liquids

The results of a series of experiments on the measurement of the angle of separation for flow over steel spheres suspended in a vertical 5.18 cm ID pipeline with and without a drag reducing aqueous polymer solution are presented. Data were obtained for sphere- to-pipe diameter ratios of 0.74 and 0.925 with polymer concentrations of 0, 25, 50, and 100 wppm over a Reynolds number range of 1633 to 29400 for single spheres and trains of up to three spheres rigidly connected. It was found that relatively dilute polymer solutions can considerably affect the separation angle. Furthermore, that the angle …

The Physical Background For Hot-Film Anemometry, G. Comte-Bellot

Symposia on Turbulence in Liquids

Thin film probes have been used for more than a decade to investigate turbulence, mostly in liquids. Many improvements have been achieved in the technique. Some problems still remain, however, so that the use of hot-film anemometers is not as straightforward as would be expected at a time when numerous ready-to-use probes and associated electronic equipment are commercially available. The following points should be discussed: aerodynamic perturbation caused by the probes, direct experimental check of the frequency response of constant temperature anemometers in the case of small fluctuations, dynamic non-linear behavior of constant temperature anemometers and heat transfer from hot …

Turbulent Pressure Spectrum Measurements On A Compliant Surface, R. N. Brown

Symposia on Turbulence in Liquids

Experimental results obtained by measuring the drag, wall pressure fluctuations, and radiated sound from a compliantly coated cylinder, 21 inches in diameter, and rotating in water are described. The compliant layer was a 1/4-inch thick closed cell, air-filled neoprene which was mounted on the 3/8-inch thick aluminum cylinder walls. Results are presented for four speed conditions; one condition is below the speed where a sudden increase in drag is obtained, and the other speed conditions are at and above this critical speed. In general, the results indicate a surface which becomes increasingly more roughened as the critical speed is exceeded.

Elucidation Of Burst Phenomena In Turbulent Boundary Layers Through Coherent Structure, W. W. Willmarth

Symposia on Turbulence in Liquids

The present knowledge of the turbulent structure of boundary layers is reviewed and summarized. The work of several primary investigators of the bursting phenomenon is discussed. Models for the coherent structure are proposed based on the results of these investigations.

Compliant Wall Surface Motion And Its Effect On The Structure Of A Turbulent Boundary Layer, R. L. Ash, D. M. Bushnell, L. M. Weinstein, R. Balasubramanian

Symposia on Turbulence in Liquids

The status of the continuing compliant wall drag reduction research at NASA-Langley Research Center is discussed. Preliminary surface motion calculations are reported along with compliant surface design concepts and their numerical models. A compliant drag reduction theory based on stabilizing the turbulent substructure is proposed and previous experiments have been examined relative to that theory. Results of recent low speed compliant surface experiments have been reported which include initial attempts to measure local compliant surface motion.

Structure Of The Viscous Sublayer In Drag Reducing Channel Flows, W. G. Tiederman, A. J. Smith, D. K. Oldaker

Symposia on Turbulence in Liquids

The objective of this study was to experimentally determine the effect of dilute, long-chain, polymer solutions upon the flow processes in a fully developed, two-dimensional turbulent channel flow. This was accomplished by making motion pictures of dye seeped through a slot into the viscous sublayer. The motion pictures were analyzed to determine the span-wise spacing and the bursting rate of the low-speed streaks that are characteristic of the sublayer structure

Front Matter, University Of Missouri--Rolla

Symposia on Turbulence in Liquids

No abstract provided.

Simultaneous Measurement Of Longitudinal Velocity And Temperature Fluctuations With A Single Wire In Non-Isothermal Flow, P. J. Mcconachie, K. J. Bullock

Symposia on Turbulence in Liquids

A method for measuring longitudinal velocity and temperature fluctuations with a single wire probe is presented and the principles of operation verified by an analog computer solution of the finite hot wire, anemometer control and signal processor equations. Examination of the basic equations reveals that such a probe is best suited to the study of turbulent water flows, thus allowing high Reynolds numbers to be attained without limitations on frequency response. Inherent sources of error are investigated and the method shown to be reliant mainly on the initial accuracy of wire calibration.

Energy Spectrum And Turbulent Scales In A Plane Air Jet, V. W. Goldschmidt, M. F. Young

Symposia on Turbulence in Liquids

The energy spectra and longitudinal length scales measured in a free plane jet are presented. The actual convective velocity was used in determining the scales. The results show a universal spectral distribution along the axis but no obvious similarity in the large scale motion off the axis. The results are limited to x/D < 60. The measured scales suggest a noticeable increase of the microscale along the lateral coordinate but an essentially constant value along the axis. However the macroscales, increasing linearly along the axis do not show any similarity off the axis.

Two-Point, Two Component, Velocity Measurements In Turbulent Pipe Flow, J. S. Cintra Jr., B. G. Jones

Symposia on Turbulence in Liquids

An experimental study of the turbulent velocity field structure was performed in a pipe flow. The primary objective of this study was to provide a detailed velocity field structure, under isothermal conditions, for use as a reference condition for later investigations of the interactions between fluctuating velocity and temperature fields, under non-isothermal conditions, in turbulent pipe flow.

Two-point, two-component (u₁ and u₂) velocity correlation measurements were made with hot-film ('x' probes) anemometers separated in the radial direction as well as two-point axial component correlation measurements with axial separation.

The fluctuating signals were analyzed digitally and both space …

The Influence Of Suction On Energy Distribution In Fully Established Turbulent Pipe Flow, M. Schildknecht, J. A. Miller, G. E. A. Meier

Symposia on Turbulence in Liquids

The influence of suction on the structure of turbulence in fully established pipe flow has been experimentally investigated. Extensive hot-wire measurements indicate major alterations in the turbulent energy distribution, particularly in the wall layers result from mild suction rates, less than 5 percent of the mean mass flow.

Unidimensional Turbulence In A Sheet Flow Under Rainfall - A Stochastic Analysis, H. L. Shahabian, A. Giorgini, J. W. Delleur, A. R. Rao

Symposia on Turbulence in Liquids

Probability distributions of longitudinal velocity fluctuations are presented for cases with and without rainfall. They deviate from the normal distribution. These velocity fluctuations are fitted by an autoregressive - moving average process. The process explains adequately the variance of the series.

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.