bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison between Measured and Computed Flow Fields in a Transonic Compressor Rotor
Authors: McDonald P. W. , Bolt C. R. , Dunker R. J. , Weyer H. B.
Published: October 2009

The flow field within the rotor of a transonic axial compressor has been computed and compared to measurements obtained with an advanced laser velocimeter. The compressor was designed for a total pressure ratio of 1.51 at a relative tip Mach number of 1.4. The comparisons are made at 100 percent design speed (20,260 RPM) with pressure ratios corresponding to peak efficiency, near surge, and wide open discharge operating conditions. The computational procedure iterates between a blade-to-blade calculation and an intrablade through flow calculation. Calculated Mach number contours, surface pressure distributions, and exit total pressure profiles are in agreement with the experimental data demonstrating the usefulness of quasi three-dimensional calculations in compressor design.
The Use of Marine Gas Turbines in an Amphibious Hovercraft, the USN AALC JEFF(B)
Authors: Coles A. V.
Published: October 2009

The Navy’s air cushion landing craft LC JEFF(B) is one of two full-scale advanced development craft that was developed and is being tested under the Amphibious Assault Landing Craft (AALC) program. The JEFF(B) was designed and built by Bell Aerospace Textron under contract to the Naval Sea Systems Command. The JEFF(B) is powered by six Avco Lycoming TF-40 gas turbines. The engines are coupled together in two sets of three engines each. The loading and control requirements resulting from this configuration, and the associated high-density spray environment, result in some unique capabilities and problems. Initial phases of development and testing of the JEFF(B) have uncovered and solved problems related to control and power matching of coupled engine systems, and to protecting the engines from the deleterious effects of salt-spray ingestion. On-line engine health monitoring systems have been developed to record compressor performance degradation due to salt ingestion.
Variable Geometry, Lean, Premixed, Prevaporized Fuel Combustor Conceptual Design Study
Authors: Fiorentino A. J. , Greene W. , Kim J. C. , Mularz E. J.
Published: October 2009

Four lean premixed prevaporized (LPP) combustor concepts have been identified which utilize variable geometry and/or other flow modulation techniques to control the equivalence ratio of the initial burning zone. Lean equivalence ratios are maintained at high power engine operating conditions for low NOx emissions, while near stoichiometric conditions are maintained at low power for good combustion efficiency and low emissions of carbon monoxide and unburned hydrocarbons. The primary goal of this program was to obtain a low level of NOx emissions (≤3 g/kg fuel) at stratospheric cruise conditions; additional goals are to achieve the currently proposed 1984 EPA emission standards over the landing/take off cycle and performance and operational requirements typical of advanced aircraft engines. Based on analytical projections made during this conceptual design study, two of the concepts offer the potential of achieving the emission goals. However, the projected operational characteristics and reliability of these concepts to perform satisfactorily over an entire flight envelope would require extensive experimental substantiation before an engine application can be considered.
Tests of an Improved Rotating Stall Control System on a J-85 Turbojet Engine
Authors: Ludwig G. R. , Nenni J. P.
Published: October 2009

An improved version of a rotating stall control system has been tested successfully on a J-85-B turbojet engine. Past tests had pointed out the desirability of increasing the response speed of the control. In this study, the installation of the stall control on the J-85 was modified so as to decrease the response time of the control by a factor of ten over that attained in the past tests. The modified control was tested to see if the decreased response time improved the ability to clear rotating stall once it has started, and also to see if rotating stall could be anticipated and prevented by proper selection of the variables in the stall control detection system. The performance of the stall control was tested by closing the bleed doors on the engine until rotating stall occurred or until the control anticipated stall and held the bleed doors open. The tests showed that the control is capable of anticipating stall before it occurs and keeping the engine completely clear of stall at speeds up to 80 percent of design speed. No tests were performed above 80 percent of design speed because opening the bleed doors at such speeds might aggravate the stall rather than clear it.
Differential Split Power Transmissions for a Single Shaft Passenger Car Gas Turbine Engine
Authors: Carriere D. L.
Published: October 2009

Descriptions, schematics, equations, and efficiency curves for a unique single shaft gas turbine engine transmission, consisting of a power splitting differential reduction gear combined with either a variable stator torque converter or variable ratio traction drive as a speed variator, and with a current production automatic four-speed gear box as a ratio expander, are contained in this paper.
Inlet Flow Distortion in Turbomachinery
Authors: Seidel B. S. , Matwey M. D. , Adamczyk J. J.
Published: October 2009

A single stage axial compressor with distorted inflow is studied. The inflow distortion occurs far upstream and may be a distortion in stagnation temperature, stagnation pressure or both. The blade rows are modelled as semi-actuator disks. Losses, quasi-steady deviation angles, and reference incidence correlations are included in the analysis. Both subsonic and transonic relative Mach Numbers are considered. A parameter study is made to determine the influence of such variables as Mach Number and swirl angle on the attenuation of the distortion.
Application of Aerodynamically Induced Prewhirl to a Small Turbocharger Compressor
Authors: Kyrtatos N. , Watson N.
Published: October 2009

A design procedure is described which allows the development of an arrangement to aerodynamically impart prewhirl to the inflow of a compressor. The procedure uses compressor performance data and inducer inlet flow distributions together with a mathematical model of the aerodynamic prewhirl inducing arrangement to arrive at the parameters which completely define an arrangement suitable for a particular compressor. The application of the procedure to design an arrangement for a small turbocharger compressor is presented. The effect of the aerodynamically imparted prerotation on the compressor performance was found to be similar to that produced by inlet guide vanes.
Bottoming Gas Turbine-Electric Plant by Immiscible Liquid Cycle
Authors: Burnside B. M.
Published: October 2009

The use of the immiscible liquid binary cycle (ILBC) to recover exhaust heat from electric utility gas turbine plant is described. In simple dual pressure plant without L.P. turbine admission, increase in specific work output compared with the steam cycle and its variation with condenser pressure, turbine efficiency and exhaust gas temperature is presented. The penalty of larger condenser surfaces is quantified. A dual pressure steam—ILBC cycle with L.P. turbine admission, which should improve on the corresponding steam cycle, is proposed.
Aerodynamic Loss in a Gas Turbine Stage with Film Cooling
Authors: Ito S. , Eckert E. R. G. , Goldstein R. J.
Published: October 2009

Experiments have been performed to measure the total pressure loss of the flow through a two-dimensional turbine cascade with “coolant” injection from a single row of holes on the suction or pressure side of the blades. The tests were performed in a low speed tunnel. Air and carbon dioxide were used as secondary fluids, the latter to provide a large density difference between the gas in the mainstream and the injected gas. Both gas streams had the same temperature. The measured pressure loss is in good agreement with analytical predictions based on a model introduced by Hartsel. The results thus provide information which can be incorporated in a program which predicts the influence of injection on the aerodynamic efficiency of a gas turbine.
The Aerodynamic Significance of Fillet Geometry in Turbocompressor Blade Rows
Authors: Debruge L. L.
Published: October 2009

This paper describes a theoretical investigation of the influence of fillet radius on the aerodynamic behavior of turbocompressors. The fillet is that found at the intersection of an airfoil and a hub or shroud where no relative motion or gap is present. A modified power law velocity is used in conjunction with experimental estimates of the three-dimensional corner boundary layer extent to obtain values of the interference displacement and friction coefficient for the 90 deg corner flow which are in fair agreement with Gersten’s experimental results. Likewise, interference displacement and friction coefficient are obtained in the case of a corner flow in a dihedral > 150 deg for which experimental data is unavailable but where the low curvature of the stream surfaces allows the three-dimensional boundary layer extent to be calculated from Bertotti’s integral momentum equation. The boundary layer characteristics thus obtained are then applied, by means of a polyhedral approximation, in the evaluation of the influence of 90 deg corner fillet on corner flow separation. Some guidelines are provided relating the fillet radius to physical dimensions of the blading.
An Evaluation of Steam Injected Combustion Turbine Systems
Authors: Brown D. H. , Cohn A.
Published: October 2009

Performance and economic evaluation results are presented for steam injected combustion turbine systems. The steam injected gas turbine plant shows a potential for low capital cost and high efficiency for sites where water consumption is not a deterrent. Steam produced in a heat recovery steam generator is injected into the gas turbine combustor section to the extent of 0.155 pounds steam per pound of air flow. Water consumption is estimated to be 2.5 pounds per kWh (1.13 kg/hWh). When burning distillate fuel at 2200°F (1204°C), the potential efficiency is 40 percent as compared to 38 percent for a simple cycle gas turbine, and the specific output per pound of air flow is increased by 30 percent. The estimated capital cost per kilowatt is 3 percent greater than that for the simple cycle gas turbine.
Water-Cooled Gas Turbine Monometallic Nozzle Development
Authors: Schilke P. W. , Blazek W. S. , Schilling W. F.
Published: October 2009

This paper describes the materials and processes development required to fabricate the second stage monometallic water-cooled nozzle for the Department of Energy funded High Temperature Turbine Technology (HTTT) program. Materials engineering and development work including alloy selection, hot isostatic pressing (HIP), and heat treat optimization necessary to fabricate this component is described and the results of this work are reported. Specialized processes utilized to achieve tight design tolerances such as TRW’s split mold investment casting and shaped tube electrode machining (STEM) are also described. The advantages of these processes are discussed in terms of the overall component design goals.
The Nutating Traction Drive
Authors: Kemper Y.
Published: October 2009

The unique torque speed characteristic of the single-shaft gas turbine requires that it have a continuously variable-ratio transmission for successful application to automotive use. This paper discusses the development of a novel mechanical transmission which has the power density required for highway vehicles. Cost and efficiency are competitive with conventional automatic transmissions.
Hydrostatic Power Splitting Transmissions Design and Application Examples
Authors: Pichard J. , Besson B.
Published: October 2009

After recalling the inventive methods used in the design analysis procedure of hydrostatic power splitting transmissions, theoretical and experimental application examples are presented. More particulars are detailed: (1) determining elements and tests results of a 230-Kw experimental transmission that can be applied to road and off-road propulsion. (2) design analysis procedure and prediction of a large ratio coverage transmission appropriate to light vehicles such as automotive cars. Conclusions are drawn as regards the future prospects of these transmissions.
A Statistical Investigation of Microstructure and Crack Growth in Titanium Alloys
Authors: Wilson D. A. , Hoeppner D. W.
Published: October 2009

Crack growth rates in various microstructures of Ti-6Al-4V and commercially pure titanium were studied using modified wedge opening load (WOL) specimens. Data were modeled using a Weibull four parameter survivorship function, selected because it meets the physical boundary conditions. The resulting models were exercised to determine the statistical significance of microstructure on the fatigue crack growth properties of these materials. Finally, inferences concerning gas turbine engine component design are considered.
Calculation of Windmilling Characteristics of Turbojet Engines
Authors: Shou Zhao Qi
Published: October 2009

The operation of a turbojet engine under windmilling conditions was analyzed and the relationship of engine speed and airflow has been derived. Replacing the efficiencies of compressor and turbine by a total pressure loss coefficient, the author was able to obtain the equations for matching the engine components and the universal curve of windmilling turbine characteristic based on theoretical analysis and experimental data. Based on the relations obtained, a simple method for calculating the windmilling characteristic of a turbojet engine was derived. In the absence of compressor and turbine characteristics under windmilling conditions, two approximate calculating methods were developed. The theoretical relations developed have been checked by experimental data. An example of the application of this approximate method is presented in the Appendix and the agreement between the prediction and experimental data is generally good.
The Effect of the Axial Velocity Density Ratio on the Aerodynamic Coefficients of Compressor Cascades
Authors: Starke J.
Published: October 2009

The aerodynamic coefficients of compressor blade sections in two-dimensional flow can easily and very accurately be determined by use of the well-known Lieblein correlations. The flow across the compressor blade sections is often quasi-two-dimensional with the axial velocity density ratio (AVDR) differing from unity. To establish simple correlations for this type of flow as well, the AVDR effect on the aerodynamic coefficients of compressor cascades is theoretically and experimentally investigated. This results in simple but accurate formulae for the calculation of the AVDR effect on the turning angle, the reference minimum-loss inlet angle, and the losses in terms of the wake momentum thickness and the diffusion ratio.
Closed-Cycle Gas Turbine Working Fluids
Authors: Lee J. C. , Campbell J. , Wright D. E.
Published: October 2009

Characteristic requirements of a closed-cycle gas turbine (CCGT) working fluid were identified and the effects of their thermodynamic and transport properties on the CCGT cycle performance, required heat exchanger surface area and metal operating temperature, cycle operating pressure levels, and the turbomachinery design were investigated. Material compatibility, thermal and chemical stability, safety, cost, and availability of the working fluid were also considered in the study. This paper also discusses CCGT working fluids utilizing mixtures of two or more pure gases. Some mixtures of gases exhibit pronounced synergetic effects on their characteristic properties including viscosity, thermal conductivity and Prandtl number, resulting in desirable heat transfer properties and high molecular weights. Typical examples of such synergetic gas mixture are helium-xenon and helium-carbon dioxide.
The Hybrid Diffuser
Authors: Adkins R. C. , Matharu D. S. , Yost J. O.
Published: October 2009

A vortex controlled diffuser has recently been reported [1], which attained high levels of pressure recovery within a short length. This diffuser has, however, achieved only a limited application because of its bleed-off requirements. The present work indicates a means by which this disadvantage can be overcome by using a hybrid arrangement of conventional and vortex controlled diffusers. The outcome was an efficient diffuser, half the length of the equivalent conical diffuser, and which would operate satisfactorily without either bleed-off or vanes projecting into the flow.
The Interrelationship between Soot and Fuel NOx Control in Gas Turbine Combustors
Authors: Blazowski W. S. , Sarofim A. F. , Keck J. C.
Published: October 2009

The decreased hydrogen content of future fuels will lead to increased formation of soot, while increased organically bound nitrogen in the fuel can result in excessive NOx emission. Control concepts for these two problems are in conflict: prevention of soot requires leaner operation while control of emissions from fuel nitrogen requires fuel-rich operation. However, recent results of two DOE research programs point to both processes having a major dependence on “hydrocarbon breakthrough.” Control of both fuel nitrogen conversion and soot formation can be achieved by primary zone operation at equivalence ratios just below that for hydrocarbon breakthrough. This paper reviews the evidence for the importance of hydrocarbon breakthrough, explains our current understanding of why hydrocarbon breakthrough is important, and offers suggestions of how these results might be applied.
Soot Formation in a Turbulent Swirl Stabilized Laboratory Combustor
Authors: Hoult D. P. , Ekchian A.
Published: October 2009

The effect of pressure and fuel composition on soot formation was studied using a high pressure, tubular laboratory burner with a swirl stabilized diffusion flame. A specially-designed water flushed probe was used to extract samples of soot and other combustion products for analysis. Measurements showed the expected increase of soot concentration with pressure only until a critical value of the Reynolds number was reached. After this point, no further increase of soot loading was observed with pressure rise. This behavior was found to be present when either kerosene or propane was used in the burner. At a suitably high Reynolds number, several fuels, closely related to JP-4, were tested in the burner. These fuel blends were constructed by adding cyclic compounds to the JP-4 so as to change its hydrogen-to-carbon ratio. It was found that the amount of soot formed scaled with this ratio, although the sooting effect of different blends with the same ratio were not identical.
Ten Years of Digital Computer Control of Combustion Turbines
Authors: Yannone R. A. , Reuther J. F.
Published: October 2009

This paper establishes the design criteria for the digital computer control systems first produced in 1969, and currently in the tenth year of history for startup, control, and monitoring of combustion turbine units in the 25–125 MW range, reviews the advantages of digital control and the fall-out obtained from the application of an advanced state-of-the-art control in the area of diagnostics and historic data handling, reviews the integration of the digital computer back-up system, composed of a solid-state fuel scheduler and logic sequencer provided for total system performance and reliability, and discusses the feasibility of a computer retrofit using existing software with the latest state-of-the-art microprocessor emulator.
Effects of Free-Stream Turbulence Intensity and Frequency on Heat Transfer to Turbine Blading
Authors: Bayley F. J. , Priddy W. J.
Published: October 2009

This paper describes a continuing experimental program in which the frequency and amplitude of turbulence in the mainstream flow over a cascade of turbine blades are separately and controllably varied. The effects of these two characteristics of the flow are demonstrated showing the significant effect of each upon the rates of convection to most of the blade surface. A correlation following the predictions of the theoretical work of reference [2] is shown to have some promise, although some modification is required to allow for changes in mainstream Reynolds number not accounted for by the usual normalizing procedure.
Comparison of Experimental and Computational Shock Structure in a Transonic Compressor Rotor
Authors: Haymann-Haber G. , Thompkins W. T.
Published: October 2009

Measurement of passage shock strength in a transonic compressor rotor using a gas fluorescent technique revealed an unexpected variation in shock strength in the radial direction. An axisymmetric idealization would normally predict that the passage shock strength would gradually weaken when moving radially inward until disappearing at the sonic radius. However, the measurements indicated a sharp peak in strength at the nominal sonic radius. Blade boundary layer separation originating at this point accounts for about one half of the total rotor losses. A numerical computation of the three-dimensional inviscid flow, using time-marching techniques, has accurately predicted in general the radial and tangential variations in passage shock strength and in particular the sharp pressure peak at the nominal sonic radius. The overall shock strength was somewhat over-predicted, but this overprediction may be the result of boundary layer separation in the experiment. This paper presents comparisons between the optical density measurements and computational results and in addition a short analytical discussion which demonstrates that the sharp shock strength rise may occur in many transonic compressor rotors.
The Nuclear Closed-Cycle Gas Turbine (HTGR-GT)—Dry Cooled Commercial Power Plant Studies
Authors: McDonald Colin F. , Boland Charles R.
Published: October 2009

Combining the modern and proven power conversion system of the closed-cycle gas turbine (CCGT) with an advanced high-temperature gas-cooled reactor (HTGR) results in a power plant well suited to projected utility needs into the twenty-first century. The gas turbine HTGR (HTGR-GT) power plant benefits are consistent with national energy goals, and the high power conversion efficiency potential satisfies increasingly important resource conservation demands. Established technology bases for the HTGR-GT are outlined, together with the extensive design and development program necessary to commercialize the nuclear CCGT plant for utility service in the 1990s. This paper outlines the most recent design studies by General Atomic for a dry-cooled commercial plant of 800 to 1200 MW(e) power, based on both nonintercooled and intercooled cycles, and discusses various primary system aspects. Details are given of the reactor turbine system (RTS) and on integrating the major power conversion components in the prestressed concrete reactor vessel.
A Study of the Viscous and Nonadiabatic Flow in Radial Turbines
Authors: Khalil I. , Tabakoff W.
Published: October 2009

A method for analyzing the viscous nonadiabatic flow within turbomachine rotors is presented. The field analysis is based upon the numerical integration of the incompressible Navier-Stokes equations together with the energy equation over the rotors blade-to-blade stream channels. The numerical code used to solve the governing equations employs a nonorthogonal boundary fitted coordinate system that suits the most complicated blade geometries. Effects of turbulence are modeled with two equations; one expressing the development of the turbulence kinetic energy and the other its dissipation rate. The method of analysis is applied to a radial inflow turbine. The solution obtained indicates the severity of the complex interaction mechanism that occurs between different flow regimes (i.e., boundary layers, recirculating eddies, separation zones, etc.). Comparison with nonviscous flow solutions tend to justify strongly the inadequacy of using the latter with standard boundary layer techniques to obtain viscous flow details within turbomachine rotors. Capabilities and limitations of the present method of analysis are discussed.
Wake Behavior in the Presence of Free Stream Turbulence
Authors: Pal S. , Raj R.
Published: October 2009

The effect of free stream turbulence on the characteristics of a turbulent wake developed from the trailing edge of a thin and smooth flat plate was studied analytically and experimentally. The experimental measurements were taken in a low speed wind tunnel using cross-wire anemometry. Two levels of free stream turbulence were obtained at the leading edge of the flat plate using grids with square bars (T∼5.23 percent) and circular rods (T∼7.23 percent). The grids were kept at distance of 273 mm from the leading edge of the flat plate. Experimental results are presented on the mean velocity profile, wake center-line velocity, half wake width, displacement thickness, and shape factor. It is shown that the free stream turbulence increases the wake recovery and growth rates. The semi-empirical correlations are developed to predict the foregoing behavior. The analytical investigation also lead to the establishment of the two turbulence parameters. These parameters simulate the effect of free stream turbulence on the wake velocity (U0) and length (L0) scales.
A Correlation for Air Velocities in Cylindrical Prechambers of Diesel Engines
Authors: Ajakaiye B. A. , Dent J. C.
Published: October 2009

Theoretical analysis and measurements of air velocities in cylindrical prechambers of the indirect injection type Diesel engine are reported. Comparisons are made between the theoretical analysis and the measurements for two cylindrical prechambers tested in the present study and the results of previous investigators [4–6], A correlation is derived-to link air velocity in the cylindrical prechamber and known engine parameters. The results show that there is poor and inconsistent agreement between theory and experiment in some of the cases considered. Reasons are suggested to explain these inconsistencies. The derived correlation could serve as an additional tool for the engine designer in predicting air motion and hence combustion and heat transfer in the prechamber of indirect injection diesel engine.
Airblast Atomization of Alternative Liquid Petroleum Fuels under High Pressure Conditions
Authors: Jasuja A. K.
Published: October 2009

A study has been conducted of the effects that fuel and air properties have upon the mean droplet size characteristics of a pre-filming airblast atomizer of the type commonly employed in the gas turbine engine. The fuels tested included kerosine, gas oil and two blends of gas oil in residual fuel oil. The tests were carried out over a wide range of air pressures (about 1 to 13 atmospheres), fuel viscosities (about 0.001 to 0.037 Ns/m2) and the spray mean drop sizes were measured using a laser light-scattering technique. The experimental data accumulated in the study is presented in the paper and it is concluded that the spray Sauter Mean Diameter performance of the atomizer studied can be predicted to a reasonable degree of accuracy, over the range of conditions studied, by a relatively simple correlating equation.
A Furnace Wall Ash Monitoring System for Coal Fired Boilers
Authors: Chambers A. K. , Wynnyckyj J. R. , Rhodes E.
Published: October 2009

This paper describes the successful development of an ash-deposit monitoring system for use in large pulverized-coal fired boilers. Using commercially proven heat flux meters the system measures the severity of ash deposition by measuring the net decrease in heat flux through the boiler walls. Testing of a prototype in two Canadian Utility boilers burning Western coals has shown that the system gives a reliable measure of the cleanliness of furnace walls and of the effectiveness (or failure) of soot blowers to remove deposits. Indications are that the system will be valuable in improving efficiency of boiler operations and in minimizing slagging and fouling problems when firing difficult coals.
The Thermodynamic Performance of Two Combined Cycle Power Plants Integrated With Two Coal Gasification Systems
Authors: Stasa F. L. , Osterle F.
Published: October 2009

Thermodynamic models of both an adiabatic and an endothermic coal gasifier integrated with either a waste heat combined cycle or a supercharged boiler combined cycle are developed. The adiabatic gasification process requires air and steam, while the endothermic gasification process requires only steam. The combined cycle is composed of an open Brayton cycle and a superheated regenerative Rankine cycle without reheat. Certain components are added to each configuration in an effort to improve thermodynamic performance. From the results, it appears that with consideration of the pollution criteria, the station efficiencies for each configuration are within 1 percentage point of each other when flue gas recirculation is used as a means to control the nitric oxide. With a gas turbine inlet temperature of 2000°F, and with consideration of the pollution criteria, the configuration employing an adiabatic gasifier and a waste heat system is marginally the best with a station efficiency of only 37 percent.
LMFBR Loss of Flow Simulations in the Sodium Loop Safety Facility
Authors: Ragland W. A.
Published: October 2009

A series of three LMFBR unprotected loss of flow (LOF) accidents has been simulated in the Sodium Loop Safety Facility (SLSF). The results of these in-reactor experiments verify that the dynamics of sodium voiding are, in general, well represented by current single channel slug expulsion models. Some refinement in the models in the very early stages of voiding would be desirable to account for minor two dimensional effects. However, cladding motion is not as well understood and current modeling does not accurately predict all of the aspects of blockage formation. Two of the three experiments produced partial rather than complete upper blockages as had been predicted. Predictions of time of fuel melting appear relatively accurate. In general, the sequence of events is correctly predicted and the timing of these events is relatively accurate. Reactivity measurements and post-test examinations indicate that no significant fuel compaction occurred. This behavior would prevent an energetic recriticality in an LOF accident.
Pellet-Cladding Interaction of LMFBR Fuel Elements at Unsteady State: An Introduction to Computer Code ISUNE-5
Authors: Ma B. M.
Published: October 2009

The fuel pellet-cladding interaction (PCI) of liquid-metal fast breeder reactor (LMFBR) fuel elements or fuel rods at unsteady state is analyzed and discussed based on experimental results. In the analyses, the heat generation, fuel restructuring, temperature distribution, gap conductance, irradiation swelling, irradiation creep, fuel burnup, fission gas release, fuel pellet cracking, crack healing, cladding cracking, yield failure and fracture failure of the fuel elements are taken into consideration. To improve the sintered (U,Pu)O2 fuel performance and reactor core safety at high temperature and fuel burnup, it is desirable to (a) increase and maintain the ductility of cladding material, (b) provide sufficient gap thickness and plenum space for accommodating fission gas release, (c) keep ramps-power increase rate slow and gentle, and (d) reduce the intensity and frequency of transient PCI in order to avoid intense stress fatigue cracking (SFC) and stress corrosion cracking (SCC) due to fission product compounds CsI, CdI2, Cs2Te, etc. at the inner cladding surface of the fuel elements during PCI.
Stalling Pressure Rise Capability of Axial Flow Compressor Stages
Authors: Koch C. C.
Published: October 2009

A procedure for estimating the maximum pressure rise potential of axial flow compressor stages is presented. A simplified stage average pitchline approach is employed so that the procedure can be used during a preliminary design effort before detailed radial distributions of blading geometry and fluid parameters are established. Semi-empirical correlations of low speed experimental data are presented that relate the stalling static-pressure-rise coefficient of a compressor stage to cascade passage geometry, tip clearance, bladerow axial spacing and Reynolds number. Blading aspect ratio is accounted for through its effect on normalized clearances, Reynolds number and wall boundary layer blockage. An unexpectedly strong effect of airfoil stagger and of the resulting flow coefficient of the stage’s vector triangle is observed in the experimental data. This is shown to be caused by the differing ability of different types of stage vector triangles to re-energize incoming low-momentum fluid. Use of a suitable “effective” dynamic head in the pressure rise coefficient gives a good correlation of this effect. Stalling pressure rise data from a wide range of both low speed and high speed compressor stages are shown to be in good agreement with these correlations.
Transonic Flow Computations in Cascades Using Finite Element Method
Authors: Akay H. U. , Ecer A.
Published: October 2009

Analysis of transonic flow through a cascade of airfoils is investigated using the finite element method. Development of a computational grid suitable for complex flow structures and different types of boundary conditions is presented. An efficient pseudo-time integration scheme is developed for the solution of equations. Modeling of the shock and the convergence characteristics of the developed scheme are discussed. Numerical results include a 45 deg staggered cascade of NACA 0012 airfoils with inlet flow Mach number of 0.8 and angles of attack 1, 0, and −1 deg.
Finite Element Methods for Transonic Blade-to-Blade Calculation in Turbomachines
Authors: Deconinck H. , Hirsch Ch.
Published: October 2009

The transonic cascade flow is calculated with an efficient and flexible Galerkin Finite Element method applied to the full potential equation in Artificial Compressibility form. Some of the typical advantages of finite element techniques are demonstrated such as the use of higher order discretization with biquadratic elements besides the classical bilinear second order accurate element, automatic treatment of the body fitted mesh due to the locally defined isoparametric mapping, easy and exact introduction of arbitrary Neumann boundary conditions along curvilinear boundaries. On the other hand, the conceptual simplicity and efficiency of the finite difference methods based on the same equation and developed for external flows are fully maintained by the use of line relaxation or approximate factorization for the iterative solution algorithm, eventually combined with a multigrid approach. The important problem of obtaining a well-constructed mesh is solved satisfactorily by automatic grid generation based on the solution of two elliptic partial differential equations. Calculations are presented and compared with experimental data for both compressor and turbine cascade flows containing shocks.
A Blockage Model for Centrifugal Compressor Impellers
Authors: Pampreen R. C.
Published: October 2009

This paper presents and discusses the results of an analysis in which the blockage distributions of four impellers were deduced from shroud static pressure measurements. The purpose of the analysis was to provide a means of estimating blockage for the jet-wake flow model for use in impeller design calculations. A parameter was investigated for correlating the blockage values against the combined effect of diffusion, curvature, and Coriolis acceleration. It was found that gross blockage accumulation correlates against this parameter with an uncertainty in blockage of ± six percentage points. Up to the point of the axial-radial bend of the flowpath, the analysis shows that blockage is controlled equally by diffusion, flowpath curvature, and the combined effect of blade curvature and Coriolis acceleration. In the radial portion of the impeller, further increase in blockage is controlled by Richardson number.
The Influence of Premixed Combustion Flame Stabilizer Geometry on Flame Stability and Emissions
Authors: Al Dabbagh N. A. , Andrews G. E.
Published: October 2009

Premixed combustion systems for gas turbines offer the possibility of low-pollution, high-combustion efficiency and good temperature distribution. They form a basis by which other well-mixed combustion systems may be assessed. The ultimate objective of this work is the development of nonpremixed rapid mixing combustion systems. Different geometries of baffle flame stabilizers are tested to study the influence of recirculation zone size and number of recirculation zones on flame stability, combustion efficiency and NOx. The results show that the flame stabilizer geometry has a major influence on combustion efficiency and flame stability but a lesser influence on NOx. Optimum equivalence ratios are identified for good combustion efficiency and low NOx at simulated low and high-power engine conditions.
Outline of Plan for Advanced Reheat Gas Turbine
Authors: Hori Akifumi , Takeya Kazuo
Published: October 2009

A new reheat gas turbine system is being developed as a national project by the “Engineering Research Association for Advanced Gas Turbines” of Japan. The machine consists of two axial flow compressors, three turbines, intercooler, combustor and reheater. The pilot plant is expected to go into operation in 1982, and a prototype plant will be set up in 1984. The major objective of this reheat gas turbine is application to a combined cycle power plant, with LNG burning, and the final target of combined cycle thermal efficiency is to be 55 percent (LHV).
Thermal Expansion Accommodation in a Jet Engine Frame
Authors: Schneider M. H.
Published: October 2009

A prime consideration in the design of turbomachinery hot section structural frames is thermal fatigue caused by differential heating of the frame basic structural elements. This paper describes the general thermal deflection pattern of a frame and some design features which can accommodate this relative expansion without excessive stress. Also discussed is a particular combination of design features which provide increased tolerance for thermal expansion while maintaining a large mechanical stiffness as is often required for a high bypass ratio turbofan engine application. This unique combination of frame design features, developed under NASA contract NAS3-20643 to NASA-Lewis Research Center with Mr. Carl C. Ciepluch as the Lewis Project Manager, represents a significant contribution to state of the art frame design.
Risk and injury portrayal in boys’ and girls’ favourite television programmes
Authors: Pfeffer K , Orum J
Published: October 2009

Objectives:

To analyse the injury-related content of children’s television programmes preferred by boys and by girls, and to determine whether there are more televised models of unsafe behaviour in programmes preferred by boys.

Methods:

Parents of 4–11-year-old children identified their children’s favourite television programmes. Content analysis of 120 episodes of children’s favourite programmes was used to quantify safe and risky behaviours, actual injuries and potential injuries. The gender of the characters portraying the behaviours was also analysed.

Results:

More risky behaviour was portrayed in the boys’ favourite programmes (mean per episode  = 6.40) than in the girls’ favourite programmes (mean = 2.57). There were almost twice as many potential injuries (n = 310) as actual injuries (n = 157). Potential injuries were portrayed more often by male characters (mean = 1.92) than female characters (mean = 0.98), mostly in the boys’ favourite programmes. Actual injuries occurred more often to male characters (mean = 1.04) than to female characters (mean = 0.27) overall.

Conclusions:

Television programmes preferred by this sample of boys portrayed male role models engaging in risky behaviours and injuries more often than the programmes preferred by the sample of girls.
Non-firearm-related homicide, New Mexico, 2001–3
Authors: Kazerouni N Neely , Shah N , Lathrop S , Landen M G
Published: October 2009

Objective:

New Mexico (NM) has the highest rate of non-firearm-related homicide in the USA and ranks 20th in firearm-related homicides. Because non-firearm-related homicides are inadequately described in the literature, characterisation of non-firearm-related homicide victims will enhance efforts to reduce homicides.

Methods:

Homicide victims were identified through the Office of the Medical Investigator. Age-specific and age-adjusted homicide death rates were calculated for 2001–3 by sex and race/ethnicity, and associations between covariates and non-firearm-related homicide were measured.

Results:

Non-firearm-related homicides comprised 33% of US homicide victims, 47% of NM homicide victims, and 74% of NM American Indian (AI) homicide victims. Of 212 NM non-firearm-related homicide victims, 37% had been beaten, 32% had been stabbed, and 12% had been strangled. Females comprised 30% of non-firearm-related homicide victims and 18% of firearm-related homicide victims. A blood alcohol concentration (BAC) ⩾0.08 mg/dl was detected among 43% of non-firearm-related (61% of AI) and 33% of firearm-related (50% of AI) homicide victims. Non-firearm-related homicide rates were highest among AI men aged 25–34 years (31/100 000). Non-firearm-related homicide victims were more likely than firearm-related victims to be AI (adjusted odds ratio (AOR) 4.20; 95% CI 2.16 to 8.16) and female (AOR 2.05; 95% CI 1.27 to 3.31), and to have had a BAC ⩾0.08 mg/dl (AOR 1.65; 95% CI 1.08 to 2.52).

Conclusions:

Homicide-prevention efforts among AIs in NM should focus on non-firearm-related homicides. The association between excessive drinking and non-firearm-related homicide should be further characterised. Continued surveillance for non-firearm-related homicides will assist these efforts.
Booster seat laws and child fatalities: a case–control study
Authors: Farmer P , Howard A , Rothman L , Macpherson A
Published: October 2009

A case–control study examined, primarily, the association between booster seat laws and fatalities among children in frontal collisions and, secondarily, the association between booster seat laws and reported restraint use, and restraint use and child fatalities. Children who died in a crash in the US were cases, and children who survived a fatal crash were controls. Subjects were child passengers (4–8 years old) in the Fatality Analysis Reporting System Database, 1995–2005. In states with a booster seat law, children were less likely to die than in states without a law (OR 0.80; 95% CI 0.66 to 0.98). They were also more likely to be restrained (adjusted OR 1.59; 95% CI 1.21 to 2.09) and were more likely to be correctly restrained (adjusted OR 4.44; 95% CI 3.18 to 6.20). It is concluded that booster seat laws are associated with a decrease in child deaths and an increase in correct restraint use among children involved in a fatal crash in the USA.
The role of alcohol in unintentional falls among young and middle-aged adults: a systematic review of epidemiological studies
Authors: Kool B , Ameratunga S , Jackson R
Published: October 2009

Objective:

To appraise the published epidemiological evidence quantifying the risk of falls associated with acute and usual alcohol consumption among young and middle-aged adults.

Design:

Systematic review.

Methods:

Data sources: searches of electronic databases (eg, Medline, EMBASE, CINAHL, PsycINFO, Scopus), websites of relevant organisations, major injury journals, reference lists of relevant articles, and contact with experts in the field. Inclusion criteria: epidemiological studies with an English language abstract investigating alcohol use as a risk factor (exposure) for unintentional falls or related injuries among individuals aged 25–60 years. Studies were critically appraised using the GATE LITE tool. Meta-analysis was not attempted because of the heterogeneity of the eligible studies.

Results:

Four case–control, three cohort and one case–crossover study fulfilled the inclusion criteria. The studies showed an increased risk of unintentional falls among young and middle-aged adults with increasing exposure to alcohol use. However, the magnitude of this risk varied considerably across studies with most estimates being relatively imprecise. Modest evidence of a dose–response relationship with acute alcohol use was observed. The association between usual alcohol use and fall risk was inconclusive, and evidence of a gender difference was inconsistent.

Conclusions:

Alcohol use appears to be an important risk factor for falls among young and middle-aged adults. Controlled studies with sufficient power that adjust effect estimates for potential confounders (eg, fatigue, recreational drug use) are required to determine the population-based burden of fall-related injuries attributable to alcohol. This can help inform and prioritise falls prevention strategies for this age group.
The effect of counting principal and secondary injuries on national estimates of motor vehicle-related trauma: a NEISS–AIP special study
Authors: Halpin J , Greenspan A I , Haileyesus T , Annest J L
Published: October 2009

Objective:

To demonstrate the effect of including both principal and secondary injuries in the calculation of national estimates of non-fatal motor vehicle-related injury, using the National Electronic Injury Surveillance System–All Injury Program (NEISS–AIP).

Methods:

The setting was a stratified sample of 15 US hospital emergency departments selected among 50 NEISS–AIP hospitals which agreed to participate in the study. Non-fatal injury data from a special study of the 2004 NEISS–AIP were analysed which allowed up to five injuries to be coded per case. National estimates of number and rate of injuries for 2004 were calculated, first using principal injuries alone, then by including principal and secondary injuries.

Results:

An estimated 4 833 626 principal and secondary injuries were sustained by the estimated 2 893 782 motor vehicle occupants involved in a crash and treated in US hospital emergency departments (EDs) in 2004. This represents a 67% increase in the total number of injuries compared with an estimate of principal injury alone. Incidence of contusions/abrasions and lower trunk injuries rose most steeply among broad injury types, and whiplash injury rose 18% in number and rate. A significantly lower percentage of cases with a single listed injury were hospitalised (5%) compared with those who sustained multiple injuries (8%).

Conclusions:

Based on an analysis of NEISS–AIP special study data, the inclusion of both principal and secondary injuries in national estimates of motor vehicle-related occupant injury would provide a more comprehensive report of non-fatal injuries treated in US hospital EDs. Other countries with ED-based surveillance systems could consider reporting multiple injuries when assessing injury count associated with motor vehicle trauma requiring ED care.