bluuebunny/crossref_metadata_2025 huggingface dataset:
The Pulsed Thermocouple for Gas Turbine Application
Authors: Kretschmer D. , Odgers J. , Schlader A. F.
Published: November 2010

A mechanically pulsed suction thermocouple has been developed. The gas to be measured is sucked through a sonic orifice, thus eliminating the influence of the velocity inside the combustor. The signal from the thermocouple is processed by an analogue circuit. Contrary to the usual approach to the problem of dynamic temperature measurements (i.e., the attempt to find an exact solution to the extrapolation of the temperature rise curve) in this work, a calibration of the probe was done. This calibration showed very little scatter and a good repeatability. The overall measurement accuracy was better than ±1 percent. As a test of application, a partial survey of the temperature distribution within an aircraft gas turbine combustor was done. A satisfactory agreement was observed between temperatures measured by the thermocouple and those determined from gas analysis. In this test the pulse thermocouple proved to be a reliable and fast tool for the measurement of local gas temperatures.
Autoignition Characteristics of Hydrocarbon Fuels at Elevated Temperatures and Pressures
Authors: Spadaccini L. J.
Published: November 2010

A problem to be treated in the design of prevaporizing/premixing combustors for use in advanced air-breathing engines is autoignition of the fuel-air mixture prior to injection into the primary combustion zone. The high combustor inlet temperatures and pressures of these engines can promote preignition and flame stabilization in premixing passages. However, data regarding the ignition delay characteristics of hydrocarbon fuels of interest, e.g., JP-type fuels and fuel oils, under conditions representative of those encountered in operating engines are not presently available in the literature. Therefore, a research program was undertaken to develop design data and criteria which will permit evaluation of the autoignition characteristics of hydrocarbon fuel-air mixtures at elevated pressures and temperatures. Measurements of the autoignition characteristics of JP-4, No. 2 fuel oil, and No. 6 fuel oil were made in dry air at temperatures in the range 750°F (400°C) to 1100°F (593°C) and at pressures in the range 100 psia (6.8 atm) to 240 psia (16.3 atm). Tests were performed in a steady-flow apparatus in which the pressure, temperature, and mixture flow rate were adjusted to induce autoignition and maintain a stationary flame front. The ignition delay time was considered equivalent to the residence time of the fuel-air mixture between the point of injection and the axial position of the flame, and it was computed from the average flow velocity. The effects of a number of physical factors, including air pressure and temperature, fuel temperature and concentration, and initial spray characteristics (e.g., droplet size and size distribution), upon the ignition characteristics were evaluated.
An Experimental Determination of the Unsteady Aerodynamics in a Controlled Oscillating Cascade
Authors: Fleeter S. , Novick A. S. , Riffel R. E. , Caruthers J. E.
Published: November 2010

A unique supersonic inlet flow field unsteady cascade experiment is described wherein the time-dependent pressure distribution within an harmonically oscillating airfoil cascade is quantitatively determined. The torsional frequency of oscillation and the inter-blade phase angle are precisely controlled by means of on-line digital computers. The dynamic data obtained include the chordwise distribution of the unsteady pressure magnitude and its phase lag as referenced to the airfoil motion. Parameters varied include the cascade inlet Mach number, the interblade phase angle, and the reduced frequency. The time-dependent data are correlated with state-of-the-art analytical predictions.
A Simple Pressure-Gain Combustor for Gas Turbines
Authors: Kentfield J. A. C. , Rehman M. , Marzouk E. S.
Published: November 2010

The performance is presented, and a description is given, of a simple pressure-gain combustor, without moving parts, which has been shown, during laboratory trials, to produce a stagnation pressure-gain across the combustor in excess of 5 percent at a combustor stagnation temperature of 3:1. It is also shown that the concept of the device appears to lend itself to development in such a way that it should be possible to incorporate successfully combustors based on the prototype in many gas turbines.
Three-Shaft Automotive Turbine-Transmission Systems of the KTT Type—Performance and Features
Authors: Kronogard S. O.
Published: November 2010

The three-shaft KTT system, a new concept in the field of vehicular gas turbines, is described. It consists of an integrated turbine-transmission system. Major engineering advances are incorporated with improvements in overall engine-transmission performance. This, in turn, improves the fuel economy, simplicity, weight, and first cost of the whole power system. A new principle is described for achieving both rapid acceleration and deceleration. The KTT system approach, because of reduced stresses, also makes possible earlier use of low-cost ceramics in high-temperature rotors. The improvements embodied in the KTT system make it possible for a gas-turbine power system of this type to seriously compete with present diesel power plants. When developed to its full potential, such a turbine package can surpass diesel capabilities by a wide margin.
Short Duration Measurements of Heating to Cooled Gas Turbine Surfaces
Authors: Consigny H. , Richards B. E. , Ville J. P.
Published: November 2010

This paper presents measurements of heat transfer to cold surfaces at conditions simulating advanced gas turbine conditions and their use to examine the range of applicability of viable predictive methods. The measurements were made under isothermal wall conditions in short duration isentropic light piston tunnels using surface temperature transient techniques. The effect of Mach number, Reynolds number, wall-to-recovery temperature ratio, surface curvature and pressure gradient on the measurements and selective prediction techniques was demonstrated.
Nonaxisymmetric Flow through Annular Actuator Disks: Inlet Distortion Problem
Authors: Hawthorne W. R. , Mitchell N. A. , McCune J. E. , Tan C. S.
Published: November 2010

The passage of distorted flow through an annular axial compressor rotor or stator is analyzed in the actuator disk limit. In such a description the flow is steady in absolute coordinates. The resulting analysis yields an overall description of the blade row performance in the presence of inlet flow defects. The present (actuator-disk) analysis is compared successfully with Dunham’s earlier three-dimensional analysis as well as with recent experimental data. In addition, comparison with a recent theory by Greitzer, employing an alternative approach, is made. The analysis shows that at least two important distinct types of vorticity arise, the one being directly analogous to the trailing vorticity (shed circulation) of classical wing theory, and the second being analogous to the vorticity occurring in “secondary flow” theory. The latter arises directly as a result of inlet distortion. The resulting varying flow angles produce spanwise variation in blade loading, and consequent trailing vorticity (Beltrami Flow). The two types of vorticity are therefore interrelated. The static pressure field is also affected by this coupling in agreement with experiment. This problem provided a striking example for which three-dimensional and two-dimensional analyses disagree qualitatively. The vorticity as viewed in coordinates fixed in the rotor is discussed in the Addendum.
Gas Turbine Commissioning Procedure
Authors: Oegerli R.
Published: November 2010

Although new, modern gas turbine power station with its control and supervisory systems are more complex than ten years ago, Brown Boveri still uses the same commissioning procedure, because of the good experience gained throughout the years. The main features are that: One commissioning engineer is responsible for the whole plant and is trained to commission all systems by himself. Specific records are provided for every unit with all settings, characteristics and special instructions in addition to general instructions, settings and characteristics. The paper explains the sequence of the works and gives an insight into: (1) Checks, tests and adjustments before shipping, (2) Commissioning work on site, (3) Commissioning schedule, (4) Commissioning personnel schedule; (5) Instrumentation and measuring equipment on site, (6) Paper work on site, reporting, (7) Acceptance tests/provisional acceptance, (8) Instruction of customer’s personnel, (9) Supervision during initial period of operation, service engineer.
Flight and Propulsion Control Integration for Selected In-Flight Thrust Vectoring Modes
Authors: Yi C. J. , Heimbold R. L. , Miller R. J. , Rachovitsky E.
Published: November 2010

The synthesis of a flight control system for an advanced air-superiority fighter equipped with jet flaps, and its flight simulator performance, is reported in this paper. Several control modes which integrate aerodynamic surfaces and engine thrust vector control are designed to enhance performance in maneuvering flight. Sustained load factor, maximum load factor, and deceleration capability are improved with the coordinated deployment of aerodynamic and propulsive control effectors. Feasibility of the control modes was verified by a fixed-base pilot-in-the-loop simulation. Air-to-air tracking results show substantial differences in fuel consumption and engine cycle fatigue rates depending on mode selection and pilot technique. Emergency modes and handling characteristics are also discussed.
Experimental Study on Flow in a Supersonic Centrifugal Impeller
Authors: Senoo Y. , Hayami H. , Kinoshita Y. , Yamasaki H.
Published: November 2010

An impeller of a supersonic centrifugal compressor was tested in a casing without a diffuser so that the flow range was not limited by the diffuser. Regarding the impeller, emphasis was placed on critical conditions such as inducer stall and surge. Experimental data were examined based on a one-dimensional analysis and a quasi-three-dimensional analysis. Furthermore, the variation of shroud pressure with respect to time at many locations was utilized to guess the details of flow behavior between impeller blades near the shroud, and the contour of isobars was compared with that predicted by a quasi-three-dimensional analysis. When the inlet relative velocity was supersonic, a detached shock wave and a shock wave in a blade channel were recognized, but the compressor operated efficiently, although such condition existed only in a narrow flow range limited by surge and choke.
The Effect of a Transversely Injected Stream on the Flow through Turbine Cascades—Part III: Influence of Aspect Ratio
Authors: Aburwin B. A. , Maccallum N. R. L.
Published: November 2010

An experimental investigation has been made of the effect of a transversely injected stream on the flow through turbine cascades similar to those in which previous studies [1, 2] had been made, but having aspect ratios of 1.5 and 1.0 compared to the previous value of 3.0. New instrumentation includes a five-hole probe. The average losses in stagnation pressure and the changes in flow capacity remain in agreement with one-dimensional theory. The exit vortex is moved towards the end-wall as aspect ratio is reduced. The strength of the vortex is diminished when the aspect ratio is reduced from 3.0 to 1.5, but there is little change for the further reduction of aspect ratio.
Growth of a Perturbation in an Axial Flow Compressor
Authors: Fabri J.
Published: November 2010

A time-dependent linearized approach is used to predict the amplification or the decay of an initial perturbation in the multistage axial compressor of high hub-to-tip ratio. This analysis shows that for unstalled flow regimes the change in perturbation amplitude remains limited. The linearized theory remains valid until the stall limit. It is shown that, near this limit, peripheral propagation of an induced perturbation takes place at an angular velocity close to one-half of rotor angular velocity. However in most cases this perturbation has a limited amplitude.
An Economic Evaluation of Small-Scale Wind-Powered Electric Generation Systems
Authors: Obermeier J. L. , Townes H. W.
Published: November 2010

Presented is an economic evaluation of several commercial wind-powered electric generation systems of the type which could be used by an individual homeowner. A system includes a wind plant, tower, storage battery, and dc to ac inverter. The analysis considered a total of 12 different system configurations. The evaluation of energy output was based on wind speed data for several locations in the state of Montana. The analysis can be extended to other locations on the basis of mean annual wind speed. The results of the evaluation indicate that some of the “home built” systems are competitive economically at the present time in some “windy” locations. None of the systems which are economic could individually supply the entire power requirement for a single-family dwelling.
Measurement of Heat-Transfer Rate to a Gas Turbine Stator
Authors: Dunn M. G. , Stoddard F. J.
Published: November 2010

A sector of the first stage stationary inlet nozzle of the AiResearch TFE-731-2 engine was instrumented with thin-film heat-transfer gages and experiments were performed to obtain detailed heat-transfer rate distributions. It is shown that the experimental apparatus can be used to study total-pressure losses in cascades. The experimental apparatus consists of a helium-driven shock tube, as a short-duration source of high-temperature high-pressure gas, driving a nozzle-test-section mounted near the exit of a primary shock-tunnel nozzle and extending into the shock-tunnel receiver tank. The nozzle-test-section device consists of a forward transition section with a circular opening facing the supersonic primary nozzle flow and with the external shape of a frustum of a cone. Internal contouring is provided to transform the circular-section subsonic intake flow into one filling a 176 deg annular segment having a geometry approximating that of the entrance to the turbine stator stage in a turbojet.
An Evaluation of Existing Two-Phase Flow Correlations for Use With ASME Sharp Edge Metering Orifices
Authors: Smith L. T. , Murdock J. W. , Applebaum R. S.
Published: November 2010

The two-phase flow correlations developed by Murdock, James, Marriott, and Smith and Leang are evaluated for the case of flow through sharp edge measuring orifices which physically meet ASME standards for flow measurement. The evaluation is based on two sets of consistent orifice flow data. The first data base consists of 34 test points for the flow of steam-water mixtures. The second data base consists of 81 data points for the flow of air-water, natural gas-water, natural gas-salt water, and natural gas-distillate mixtures. The root mean square fractional deviation of each correlation is used to determine its predictive reliability. Computed root mean square fraction deviations for steam-water flows are: James, ±0.081; Marriott, ±0.114; Murdock, ±0.141; Smith and Leang, ±0.218. For the case of gas-liquid flows, the values are: Murdock, ±0.074; James, ±0.178; Smith and Leang, ±0.183; Marriott, ±0.458.
Oil Conservation in Home Heating
Authors: Hayden A. C. S. , Braaten R. W. , Brown T. D.
Published: November 2010

Field studies of the oil consumption characteristics of oil-fired residential heating systems have been carried out in several homes in a severe winter climate. Daily recording of the fuel consumption, cycling frequency and cycle length allowed the data to be used in conjunction with hourly meteorological records to establish baseline consumption patterns for comparison with consumption levels measured during the use of selected residential oil conservation techniques. Improved burner performance and overnight thermostat cutback are each shown to offer greater fuel savings than the use of a positive chimney damper designed to minimize “off” cycle losses.
Steady-State Performance of Squeeze Film Damper Supported Flexible Rotors
Authors: Rabinowitz M. D. , Hahn E. J.
Published: November 2010

The synchronous steady-state operation of a centrally preloaded single mass flexible rotor supported in squeeze film bearing dampers is examined theoretically. Assuming the short bearing approximation and symmetric motions, frequency response curves are presented exhibiting the effect of relevant system parameters on rotor excursion amplitudes and unbalance transmissibilities for both pressurized and unpressurized lubricant supply. Hence, the influence of rotor flexibility, rotor mass distribution, rotor speed, bearing dimensions, lubricant viscosity, support flexibility can be readily determined, allowing for optimal rotor bearing system design. It is shown that with pressurized bearing mounts, the possibility of undesirable operation modes is eliminated and a smooth passage through the first pin-pin critical speed of the rotor is feasible, while absence of pressurization significantly limits the maximum safe unbalance in the vicinity of this critical speed. Significant decrease in transmissibility and rotor excursion amplitudes over those obtainable with rigid mounts are shown to be a practical possibility, with consequent decrease in the vibration level of the rotor mounts and prolongation of rolling element bearing life, while maintaining acceptable rotor vibration amplitudes. A design example is included to illustrate the use of the data.
A Rational Analysis of Periodic Flow Perturbation in Supersonic Two-Dimensional Cascade
Authors: Ni Ron-Ho
Published: November 2010

An analytical formulation which can be applied to obtain unsteady aerodynamic solutions for a cascade of flat plate blades oscillating in subsonic or supersonic flow with either subsonic or supersonic axial velocity component is presented. In the analysis, the flow is assumed to be two-dimensional and isentropic and the blades are undergoing small amplitude harmonic oscillations. The method of superposition of basic wave solutions of the linearized unsteady flow equation is used to construct the flow field induced by the harmonic motion of blades in cascade. This method leads to an integral equation from which the unsteady loading on a blade can be determined. Since the equation applied to both subsonic and supersonic inlet conditions, the present approach provides a unified basis for analyzing and understanding the complex physical phenomena associated with flow past vibrating cascades. The technique used to determine a solution for an unsteady supersonic cascade is also described and the results obtained are shown to agree with those from previous solution.
On The Nature of Jets Entering A Turbulent Flow: Part A—Jet–Mainstream Interaction
Authors: Kadotani K. , Goldstein R. J.
Published: November 2010

The effects of mainstream turbulence intensity between 0.3 percent and 20.6 percent and turbulence scale between 0.06 and 0.33 jet entrance diameters on heated and unheated subsonic jets issuing from a row of inclined round holes into a turbulent boundary layer are reported. Time averaged and instantaneous velocities and the mean temperature are measured in the flow. The mainstream turbulence scale has a significant effect on the temperature distribution of the injected jets and on the instantaneous velocity profiles of the flow following injection. When the mainstream turbulence scale is large, the injected jets are well mixed with the mainstream; when the scale is small, the injected jets are well preserved and the effect of vortex motion upon the temperature distribution becomes significant.
On the Nature of Jets Entering A Turbulent Flow: Part B—Film Cooling Performance
Authors: Kadotani K. , Goldstein R. J.
Published: November 2010

The effects of mainstream turbulence intensity between 0.3 percent and 20.6 percent and turbulence scale between 0.06 and 0.33 jet entrance diameters on heated subsonic jets issuing from a row of inclined round holes into a turbulent boundary layer are investigated from the view point of film cooling effectiveness. At low blowing rate the injected jets stay close to the wall and are sensitive to the turbulent mixing resulting in a decrease of centerline effectiveness with an increase of mainstream turbulence intensity. At high blowing rate the centerline effectiveness increases with the mainstream turbulence intensity because of smaller penetration of the injected jets due to the greater mixing with the mainstream and to the thinner boundary layer of the mainstream. At moderate turbulence intensity, the turbulence scale has a significant effect upon the lateral distribution of effectiveness through vortex formation.
Critical Regimes of Coal Ignition
Authors: Annamalai K.
Published: November 2010

In a normal operation of the coal fired power plant, critical regimes exist where the particles cannot be ignited either in the gas mode or in the heterogeneous mode due to excessive heat loss. Following thermal theories of ignition, sufficient conditions for the extinction sizes for quenching gas phase combustion are presented along with critical limits for the gas phase and heterogeneous ignition of coal particles. Universal plots are given to present the critical parameters of both modes of ignition in terms of known physico-chemical data of any coal/char particle. Quantitative results for the critical size and oxygen concentration of brown coal particles estimated from the plots are found to check with the iterative numerical results carried out elsewhere. Such sizes and oxygen concentrations may serve as ignitability indices of different coal particles.
Corrosion and Fouling Potential in Diesel Exhausts
Authors: Engel P. K. , Thompson R. E. , Silvestrini R.
Published: November 2010

The exhaust gases from five large diesel engines—1500 to 6400 kW (2000 to 8900 hp)—were sampled at three sites over a range of engine operating conditions using fuels with 0.05 percent to 0.8 percent sulfur. Measurements of SO2, SO3, CO, CO2, H2O, NO, NOx, chlorides, acid dew point, peak rate temperature of acid deposition, particulate loading, particle sizing, particulate composition and smoke number were made to characterize the diesel exhaust. In the diesel exhaust, all of the fuel sulfur was converted to SO2, SO3, and other sulfur oxides. The SO3 as a fraction of the total SOx ranged from 2 percent to 8 percent varying inversely with fuel sulfur content. The average conversion to SO3 was 3 percent. Acid dew point measurements were successfully obtained for a medium sulfur fuel (0.8 percent) and were correlated within 4°C with empirical predictions. Under typical diesel operating conditions the acid dew point varied from 112 to 117°C (234 to 242°F) for this fuel. Total particulate emissions varied directly with fuel sulfur content. Fifty percent or greater of the total particulate emissions were less than or equal to 0.3 μm in size. The fouling and corrosion potential of diesel exhaust gas can be approximated given the fuel analysis and engine operating conditions.
The Value of Prototype Testing in the Development of the In-Vessel Handling Machine for FFTF
Authors: Sharbaugh J. E.
Published: November 2010

Refueling system components for LMFBR’s require a high degree of accuracy because of the need to function remotely without visual access. Also, they must have proven reliability to assure minimum plant outage for reactor refueling. The experience gained in the development of the in-vessel handling machine (IVHM) for the Fast Flux Test Facility reactor dramatically indicates that construction, testing, and modification of the design are an essential part of the development of this type of equipment. It is suggested that design and development schedules for this type of equipment must allow for production and testing of prototypes to assure that functional requirements of plant equipment will be achieved. The money spent on such testing must be considered as an investment rather than as a direct cost, with the return on investment being high reliability and consequently high plant availability. The IVHM is described briefly, and some specific lessons learned during prototype testing are presented.
The Relative Value of Energy Derived From Municipal Refuse
Authors: Hecklinger R. S.
Published: November 2010

Many systems for utilizing the heat energy in municipal refuse are in various stages of development. These systems either use unprocessed solid waste as a fuel or derive a fuel through processing. The fuels produced vary radically in heating value. The energy expended in processing differs from one process to another and the potential end use is not the same for each system. Six representative systems are compared to determine the relative potential value of refuse as a source of energy.
The Reduced Drag of Polymer Solutions in Turbulent and Transient Laminar Shear Flows
Authors: Hansen R. J.
Published: November 2010

The laminar flow of a polymer solution near a flat plate of infinite extent is investigated theoretically for three cases: (a) the plate is impulsively started and moves in its own plane with a constant velocity; (b) it executes linear harmonic oscillations in its own plane; (c) its motion in this plane is a random function of time. In each case the mean square value of the drag exerted on the plate by the polymer solution is predicted to be less than that by a Newtonian fluid of the same viscosity and density. The results are combined with a simple model for the turbulent boundary layer, and a number of experimentally observed characteristics of the turbulent flow drag reduction phenomenon are predicted. The merits of this transient shear explanation for the unusual behavior of polymer solutions in turbulent flow are compared to those of previously offered hypotheses.
The Oscillatory Boundary Layer Growth Over the Top and Bottom Plates of a Rotating Channel
Authors: Kurosaka M.
Published: November 2010

The behavior of the steady boundary layers formed over the top and bottom surfaces of a rotating channel is theoretically investigated. At the leading edge, not surprisingly, the flow behaves in accordance with the Blasius solution. Far downstream, the boundary layers are established as an Ekman layer. The transition from the Blasius layer to the Ekman layer is not monotonously smooth, but occurs in a spatially wave-like manner. This undulatory transition zone results from the Coriolis coupling between the motion in the main and cross flow directions. The length of the transition zone is relatively short, occuring within a few cycles of the aforementioned undulations.
Turbulence Structure for Fully Developed Flow in Rough Pipes
Authors: Powe R. E. , Townes H. W.
Published: November 2010

This paper presents the results of an experimental study of fully developed turbulent flow in rough pipes. The investigation was undertaken in an attempt to better understand some of the changes in turbulence structure which accompany a change in wall roughness, and the experimental results include energy spectra of the fluctuating velocities in each coordinate direction, as well as microscales and macroscales of turbulence. The results indicate that the turbulence structure in the central region of the pipe is relatively independent of surface roughness, while the structure near the wall is very much dependent on the nature of the solid boundary. For hydraulically smooth flow, the principal effect of the wall is to radially suppress the extent of the larger eddies in the flow field. In the transition regime, the longitudinal extent of both large and small eddies is disrupted by the roughness elements, and the dissipation eddies appear to be stretched radially as they intermesh with the sand grains. The large eddies are almost completely obliterated by the roughness particles in the fully rough flow regime, while a tendency toward isotropy of the small eddies is noted. Thus, very definite changes in the flow structure occur as wall roughness is varied, and it is postulated that these changes are due principally to the fact that the roughness elements occupy the space where the three-dimensional streaky structure originates in smooth pipe flow.
The Measurement and Effects of Edge Sharpness on the Flow Coefficients of Standard Orifices
Authors: Crockett K. A. , Upp E. L.
Published: November 2010

An investigation of the lead foil impression technique of determining orifice edge-sharpness and the resultant effects on orifice coefficient of the rounding of the square-edge as determined by water calibration are discussed. The data to date are encouraging and correlate well with similiar work done originally in Germany and more recently in England.
A Note on the Critical Pressure Ratio Across a Fluid Meter
Authors: Benedict R. P. , Schulte R. D.
Published: November 2010

The concept of critical static pressure ratio across a fluid meter is first discussed. Various formulations for critical pressure ratios are then developed and solutions are tabulated for convenience. Conclusions, based on graphical and numerical studies, are drawn as to which critical pressure ratios apply in the various supercritical formulations.
An Initial Value Method for the Study of Shock-Induced Laminar Compressible Boundary Layers
Authors: Vimala C. S. , Nath G.
Published: November 2010

An initial value method is applied for investigating laminar compressible boundary layers created by the passage of a plane shock wave over an infinite flat plate. The two point boundary value problem is reduced to an initial value problem by using the theory of transformation groups and is then integrated by Runge-Kutta-Gill method. The advantages of this method over the methods employed usually are that it gives good results without initial guesses and iterative processes and it is simple and direct both in concept and in application.
Vortex Shedding From Slender Cylinders of Various Cross Sections
Authors: Mujumdar Arun S. , Douglas W. J. M.
Published: November 2010

Vortex shedding frequencies were measured for a number of cylinders of various geometrical shapes by placing a hot-wire sensor in the near wake and autocorrelating the turbulence signal. Strouhal numbers are presented for D-section cylinders with the flat face facing both upstream and downstream, isosceles triangular prisms, axially corrugated and helically grooved circular cylinders. For the triangular prisms effect of angle of attack was also studied. Effect of surface roughness on shedding from circular cylinders was observed to be negligible.
Laterally Integrated Numerical Water Quality Model for an Estuary
Authors: Spaulding M. L.
Published: November 2010

The development of a two-dimensional, laterally integrated, estuarine, numerical water quality model is presented. The model is then applied to Narragansett Bay’s D.O.-B.O.D. system and shows good agreement with existing data in predicting vertical structure. Application of the model to storm-sewage overflow for the Bay also shows favorable comparison to existing data.
A Note on Several Theories of Turbulence in a Uniform Shear Flow
Authors: Mulhearn P. J.
Published: November 2010

Several theories for the development of turbulence in a uniform shear flow are compared with experiments. Greatest success is found with theories which model the Reynolds stress equations. Improvement of these theories however requires a better understanding of the turbulence interactions which transfers energy between fluctuating velocity components.
A Method of Measuring Three-Dimensional Rotating Wakes Behind Turbomachinery Rotors
Authors: Lakshminarayana B. , Poncet A.
Published: November 2010

A method of measuring the mean velocities and turbulence intensities in a rotating wake behind a turbomachinery rotor is developed. The method utilizes three stationary hot wires located in three coordinate directions. The signal is processed through analog-digital converter unit and the digital computer to derive three-dimensional velocity and turbulence intensity profiles across the wake.
Instabilities of a Spatial System of Articulated Pipes Conveying Fluid
Authors: Bohn M. P. , Herrmann G.
Published: November 2010

A spatial system of two articulated pipes conveying fluid is examined analytically and experimentally. As the flowrate is increased, stable equilibrium may be lost by either divergence (static buckling) or by flutter (oscillations with increasing amplitude), depending upon the value of an angle β which measures the “out-of-planeness” of the system. It is found that in the range O < β < 90 deg there exists a transition value β* below which stability is lost by flutter and above which stability is lost by divergence.
Design and Construction of a Wind Tunnel for Mass Transfer Studies in Incompressible Boundary Layers
Authors: Watts K. C. , Brundrett E. , Nicoll W. B. , Strong A. B.
Published: November 2010

The apparatus of previous workers are described in order to evaluate the need for further studies of mass transfer into turbulent boundary layers. The apparatus built at the University of Waterloo is then described with particular reference to the areas where it is felt that significant improvement has been achieved over other apparatus. Some suction data obtained on the present apparatus is presented.
Analysis of Pressure Wave Reflection in the Male Urethra for the Purpose of Diagnosing Obstructions
Authors: Lai-Fook S. J. , Gessner F. B.
Published: November 2010

This paper investigates the feasibility of diagnosing intraurethral obstructions in males by means of a pressure pulse technique. Initial discussion centers on some of the anatomical and physiological characteristics of the male lower urinary tract for both normal and abnormal (obstructed) conditions. Present methods of diagnosis are reviewed and the limitations of these techniques are discussed. An alternate method of diagnosis is then described which is based on examination of wave reflection behavior in the urethra during micturition after a pressure pulse is generated by means of quick-acting valve downstream of the meatus. Numerical results based on a proposed analytical model show that reflected waves from upstream obstructions can be detected, even for partial valve closure, and that induced peak pressures can be maintained within acceptable physiological limits. These results imply that the technique should be useful as a means of diagnosing obstructions in the male lower urinary tract.
The Prediction of Swirl and Inlet Turbulence Kinetic Energy Effects on Confined Jet Mixing
Authors: Hendricks C. J. , Brighton J. A.
Published: November 2010

Mixing of a turbulent jet with a coaxial slower-moving secondary stream in a constant diameter tube was investigated. Of special interests were the effects of swirling the jet and initial turbulence kinetic energy. The analysis involved a numerical solution of the governing flow equations which were simplified by the Prandtl boundary layer assumptions. The two unknown turbulent stresses in the flow equations were modeled by defining an isotropic effective viscosity. The effective viscosity was calculated from a two-equation model of turbulence. The turbulence model was modified for swirling flows. Predicted results were compared with experimental results of several investigators. Good agreement was obtained when calculated results were compared with mean velocity and wall pressure data. The addition of swirl to the jet increased the rate of spread of the jet and resulted in decreasing the axial length required for mixing. The initial turbulence levels of the streams were found to have a significant effect on the distribution of mean velocity and pressure. This dependence has not been considered by most investigators and makes it imperative that experimentalists include turbulence information in their presentation of results.
Direct Measurement of High-Pressure Gas Density With an Ion-Chamber Densitometer
Authors: Friar B. W. , Glower D. D. , Marco S. M.
Published: November 2010

The dependence of ion-chamber current on the density of the filling gas has been investigated, experimentally and analytically, to explore the use of an ion chamber as a high-pressure gas densitometer. A flat-plate ion chamber with a self-contained beta-particle source (Sr90-Y90) was used in experiments with methane, nitrogen, and carbon dioxide and for pressures up to 2000 psia and densities up to 9 lbm/ft3. Over an appreciable density range, the linearity of the current-density response was good with a static sensitivity of about 10−10 amp/(lbm/ft3) and a reproducibility of ±0.5 percent. Variables which could be used to increase the static sensitivity and the linear range were identified.
Parallel Porous Plate Channel Flow Characteristics Resulting From Nonuniform Entry Velocity Profiles
Authors: Doughty J. R.
Published: November 2010

The author has found a class of entry velocity profiles that develop into the Raithby fully developed second solution for flow in a parallel porous plate channel with strong suction. The entry profiles of interest are characterized by a velocity defect at the channel centerline. Two numerical solution techniques are employed. The faster first technique involving solution of the boundary layer equations is used to predict overall trends of profile development. The boundary layer solutions are compared to exact solutions of the Navier-Stokes equations. A detailed examination was made of the double Poiseuille entry condition which was found to develop into Raithby’s profile.
Effect of Specific Heat Ratio, Impeller Tip Running Clearance, and Compressor Insulation on High-Pressure-Ratio Centrifugal Compressor Modeling
Authors: Block J. A. , Runstadler P. W.
Published: November 2010

Results are displayed which show the effect of gas specific heat ratio, impeller tip running clearance, and compressor insulation on modeling of a high-pressure-ratio compressor’s performance. The data were obtained using a low-speed-of-sound gas and a compressor previously tested extensively in air. Duplication of the air inlet specific heat ratio was found to be essential to modeling the air-equivalent flow rate accurately. Stage pressure ratio and stage efficiency were found to be less sensitive to the accurate replication of the air specific heat ratio. For the compressor tested, stage isentropic efficiency increased as impeller-to-shroud tip running clearance was reduced from 15 to 5 percent of the impeller tip axial depth. The measured stage efficiency was found to depend strongly on the heat transfer between the compressor and surroundings.
Perturbation Solutions for Steady One-Dimensional Waterhammer Waves
Authors: Walker John S.
Published: November 2010

The steady-state form of a plane waterhammer wave is considered in order to illustrate the application of perturbation methods to fluid transients. An asymptotic solution is obtained for small Mach numbers. The jump conditions are determined and a solution for the internal, viscous structure of the wave is found.
The Influence of Air and Liquid Properties on Airblast Atomization
Authors: Rizkalla A. A. , Lefebvre A. H.
Published: November 2010

An experimental study of airblast atomization has been conducted using a specially designed atomizer in which the liquid is first spread into a thin sheet and then exposed on both sides to high-velocity air. The first results of this study, reported in reference [1], were confined to the effects of liquid properties, namely, viscosity, surface tension, and density on atomization quality. Since then the experimental data have been extended to include the influence of air properties, notably temperature and pressure, on-mean drop size. The purpose of this paper is to present these data and to show that the effects of both air and liquid properties on atomization quality are described by the following dimensionless equation: SMD/t=A(σeρe/t)0.5(Vaρa)−1.0(1+We/Wa)+B(ηe2/σeρat)0.425(1+We/Wa)2
Prediction of Turbulent Jets in Coflowing and Quiescent Ambients
Authors: Madni I. K. , Pletcher R. H.
Published: November 2010

Some existing turbulence models for the round jet in coflowing and quiescent ambients are compared to experimental data, and some modifications are suggested and examined. A new model is proposed which results in consistently good predictions for a wide range of velocity ratios, including the important case of a jet discharging into an ambient at rest. The conservation equations of mass, momentum, and energy in differential form for the jet flow are solved numerically in the physical plane using an explicit difference scheme of the DuFort-Frankel type.
Measurements in Fully Developed Turbulent Channel Flow
Authors: Hussain A. K. M. F. , Reynolds W. C.
Published: November 2010

Measurements in a turbulent channel flow of air are presented for three Reynolds numbers. The design features of the present system suggest that the flow is a closer approximation to fully developed, two-dimensional turbulent flow between two parallel plates than those documented by previous investigators. Comparison of the new data with previous data reveal distinct differences, some of which can be attributed to differences in apparatus design. Interest in these data stems from the fact that channel flow serves as a reference flow for testing various theoretical models and experimental techniques involving turbulent shear flows.
Turbulent Mixing and Reacting Flow Characterization
Authors: Morgenthaler J. H.
Published: November 2010

Complex turbulent mixing and reacting flows must be characterized in greater detail than is currently possible if analyses are to yield meaningful guidance in the design of practical hardware. An assessment is made of the relative importance of turbulent mass, momentum, and energy transport, and mass transport (mass mixing) demonstrated to be more significant than either energy or momentum transport for a coaxial hydrogen jet reacting with an external high-temperature air stream. A technique is presented for developing and evaluating mixing models, applicable to both reacting and nonreacting flows, in which experimental mean concentration, velocity, and density profiles are differentiated directly, and local transport coefficient distributions obtained.
The Limitations of Solutions of a Third-Order Differential Equation Arising in the Asymptotic Expansions in Radial Jets
Authors: Utz W. R.
Published: November 2010

It is shown that an equation arising in a study of the asymptotic expansions in radial jets is limited to one meaningful coefficient value.
Velocity Correlation and Vortex Spacing in the Wake of a Vibrating Cable
Authors: Ramberg S. E. , Griffin O. M.
Published: November 2010

The von Karman vortex streets formed in the wakes of vibrating, flexible cables were studied using hot wire anemometers. The experiments took place in or at the boundaries of the flow regime where the vibration and vortex-shedding frequencies lock together, or synchronize, to control the wake formation. Spacial cross-correlations of the wake velocity signals were made for Reynolds numbers between 400 and 1300. Within the synchronized region, the magnitude of the measured spanwise cross-correlation coefficient is seen to approach unity, being limited by turbulence but apparently independent of frequency, amplitude, and Reynolds number. The bounds of the lock-in regime are determined and compare remarkably well with previous vibrating, rigid cylinder results. Further, the downstream longitudinal vortex spacing and induced street velocity are also found to compare well with vibrating cylinder results.
Optimal Selection of Pumps in an Hydraulic Network
Authors: Conry T. F. , Schneider D. P.
Published: November 2010

The selection of pumps in an hydraulic network (such as those found in plant firewater systems or hydraulic control systems) is formulated as a mixed integer nonlinear program. The design objective is to minimize the total relative pump first cost. The piping network is assumed to exist and hence is not modified during the optimization process. A method is given for the transformation of the mixed integer nonlinear program into a mixed integer separable program. This formulation allows the use of efficient algorithms for the design of hydraulic networks. It also offers an alternative for the analysis of hydraulic networks. This technique may also be used for the analysis and design of general networks with nonlinear elements subject to convexity conditions. Two examples are given which consider an analysis problem and a design problem.
A Separated and Reattached Flow on a Blunt Flat Plate
Authors: Ota Terukazu , Itasaka Masaaki
Published: November 2010

Velocity, pressure, and turbulence measurements were made in the separated, reattached, and redeveloped regions of a two-dimensional incompressible flow over a flat plate with finite thickness and blunt leading edge. Flow characteristics, such as the reattachment length and the flow pattern in the separated region, were determined. The boundary layer characteristics of the flow downstream of the reattachment point are presented through various experimental results.
Steam Flow Through Safety Valve Vent Pipes
Authors: Brandmaier H. E. , Knebel M. E.
Published: November 2010

The flow of steam through a safety valve vent pipe system has been analyzed to provide a design basis for sizing the pipe to prevent blowback of steam. The analysis is based upon the application of modern fluid dynamics to the flow in ejectors and free-jet wind tunnels. The resulting vent pipe design procedure is, in the authors’ opinion, based upon a more realistic analysis than has previously been performed.
Turbulent Mixing of Coaxial Jets With Particular Reference to the Near-Exit Region
Authors: Ribeiro M. M. , Whitelaw J. H.
Published: November 2010

Measurements, obtained with hot wire anemometry, are reported in a co-axiol jet flow where the inner and outer initial maximum velocities were the same. The hot-wire signal was processed with a modified, linearized procedure which is described. The downstream results show that the coaxial jet develops more rapidly than a single jet but that, for example, the Reynolds shear stress has not attained a self-preserving condition at a distance of 30 external diameters. Particular attention was paid to the region of the wake of the pipe wall and two dominant frequencies were observed, corresponding to two orthogonal velocity components. The high frequencies of these fluctuations indicate that they must be regarded as turbulent fluctuations and, as might be expected, lead to regions of almost constant Prandtl and Prandtl-Kolmogorov length scales.
Measurements of Velocity Wave Forms in the Dog Aorta
Authors: Kiser K. M. , Falsetti H. L. , Yu K. H. , Resitarits M. R. , Francis G. P. , Carroll R. J.
Published: November 2010

Hot film needle and catheter probes were used to measure the velocity waves in the dog aorta between the aortic valve and the iliac bifurcation. The forms of the waves were found to be of two types, those in which there was a reverse flow, following systole, everywhere along the centerline of the aorta and those for which there was no flow reversal in the regions below the diaphragm. Energy spectra were measured before and after the administration of a cardiac stimulant. Except for a shift to higher frequencies, no significant change in the form of the spectra was observed. Characteristic times developed for the mean flow and the decay of a fully developed turbulence suggest that it is difficult to sustain small scale turbulence which might be initiated during peak systole.