bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Blade Tip Geometry on the Tip Leakage Flow in Axial Turbine Cascades
Authors: Heyes F. J. G. , Hodson H. P. , Dailey G. M. 
Published: March 2015

The phenomenon of tip leakage has been studied in two linear cascades of turbine blades.The investigation includes an examination of the performance of the cascades with a variety of tip geometries. The effects of using plain tips, suction side squealers and pressure side squealers are reported. Traverses of the exit flow field were made in order to determine the overall performance.
A method of calculating the tip discharge coefficients for squealer geometries is put forward. In linking the tip discharge coefficient and cascade losses a procedure for predicting the relative performance of tip geometries is developed. The model is used to examine the results obtained using the different tip treatments and to highlight the important aspects of the loss generation process.
Computation of a Wall Boundary Layer With Discrete Jet Injections
Authors: Kulisa P. , Leboeuf F. , Perrin G. 
Published: March 2015

Cooling of turbine blades is often achieved with cold discrete jets introduced at the wall. In this paper, a new method for computation of a wall boundary layer with discrete jet interactions is presented. The jets are assumed to be arranged in rows and the flow is assumed locally periodic in the row direction.
The conservation equations are spatially averaged between two jet orifices. The resulting equations look like two-dimensional boundary layer equations, but with three-dimensional jet source terms.
The numerical method solves the boundary layer equations with a Keller box method. A strong interaction with inviscid flow is also introduced in order to avoid numerical difficulty in the jet region. Three-dimensional jet conservation equations are solved with an integral method, under the boundary layer influence. A coupling of the two methods is performed.
Comparisons with low speed experimental data are presented, particularly near the jet orifices. It is shown that the agreement between the results of computation and the experiments depends on the jet behaviour very near to the jet exit.
Design of a High Performance Axial Compressor for Utility Gas Turbine
Authors: Sehra A. , Bettner J. , Cohn A. 
Published: March 2015

An aerodynamic design study to configure a high efficiency industrial-size gas turbine compressor is presented. This study was conducted using an advanced aircraft engine compressor design system. Starting with an initial configuration based on conventional design practice, compressor design parameters were progressively optimized. To further improve the efficiency potential of this design, several advanced design concepts (such as stator ends bends and velocity controlled airfoils) were introduced. The projected polytropic efficiency of the final advanced concept compressor design having 19 axial stages was estimated at 92.8 percent, which is 2 to 3 percent higher than the current high efficiency aircraft turbine engine compressors.
The influence of variable geometry on the flow and efficiency (at design speed) was also investigated. Operation at 77 percent design flow with inlet guide vanes and front five variable stators is predicted to increase the compressor efficiency by 6 points as compared to conventional designs having only the inlet guide vane as variable geometry.
Unsteady Rotor Dynamics in Cascade
Authors: Lee Yu-Tai , Bein Thomas W. , Feng Jin Zhang , Merkle Charles L. 
Published: March 2015

A time-accurate potential-flow calculation method has been developed for unsteady incompressible flows through two-dimensional multi-blade-row linear cascades. The method represents the boundary surfaces by distributing piecewise linear-vortex and constant-source singularities on discrete panels. A local coordinate is assigned to each independently moving object. Blade-shed vorticity is traced at each time step. The unsteady Kutta condition applied is nonlinear and requires zero blade trailing-edge loading at each time. Its influence on the solutions depends on the blade trailing-edge shapes.
Steady biplane and cascade solutions are presented and compared to exact solutions and experimental data. Unsteady solutions are validated with the Wagner function for an airfoil moving impulsively from rest and the Theodorsen function for an oscillating airfoil. The shed vortex motion and its interaction with blades are calculated and compared to an analytic solution. For multi-blade-row cascade, the potential effect between blade rows is predicted using steady and quasi unsteady calculations. The accuracy of the predictions is demonstrated using experimental results for a one-stage turbine stator-rotor.
Unsteady Aerodynamic Response of a Cascade to Nonuniform Inflow
Authors: Caruthers John E. , Dalton William N. 
Published: March 2015

A solution method is developed for the small perturbation approximation to the inviscid, unsteady fluid equations for a 2-D cascade of airfoils. By introducing the unsteady field as a locally small perturbation from a nonuniform steady field, a first order coupling between the unsteady fluid properties and the gradients of the steady field properties results.
Results of this analysis procedure are compared with the experimentally determined unsteady pressure distribution on the vane of a low speed research compressor produced by the wakes from the upstream rotor. Correlation between experimental and analytical results is good. Similar comparisons of the data with an analysis method which approximates the vane as a 2-D cascade of flat plates at zero mean incidence did not exhibit acceptable correlation. The lack of correlation was particularly evident for the chordwise phase angle distribution.
Computer-Assisted Manufacturing of a Low Thermal Stress Gasturbine Inner Casing
Authors: Brinkmann Jürgen , Dietrich Peter 
Published: March 2015

This technical paper describes the computer-assisted manufacturing of a newly developed gas turbine inner casing designed by Siemens/KWU for hot gas temperatures up to 1350 °C.
After explaining the most important design features, double wall casing with intensive impingement cooling, and details on the special materials involved, the manufacturing sequence and requisite special manufacturing techniques are described. The significant advantages and benefits of a CAD/CAM system tailored to the respective technique employed for this key aerodynamically-optimized item of a stationary gas turbine are elucidated in light of economic concerns and quality requirements and conditions imposed.
In conclusion, the transferability of the design principle described in this paper and its implementation in future-oriented developments in fabrication techniques employed in the manufacture of hot-gas-path casings at even higher temperatures are discussed.
Development of a 220-MW Coal-Fired Combustion Turbine Combined Cycle: Current Status
Authors: Pillsbury P. W. , Bannister R. L. , Diehl R. C. , Loftus P. J. 
Published: March 2015

In the eight-year, multicontractor program to develop a 220-MW coal-fired combustion turbine combined cycle plant, the team is now into its third year of subscale slagging combustor testing. Because of an ability to accept unbeneficiated, utility-grade coal, the slagging combustor is the key to the direct coal-fired combustion turbine. The projected plant will contain two 80-MW combustion turbines equipped with slagging combustors, two heat recovery steam generators, and a 65-MW steam turbine.
In testing to date, the concept has demonstrated its ability to handle high- and low-sulfur bituminous coals, and low-sulfur subbituminous coal. Feeding the fuel in the form of pulverized coal has proven to be superior to coal-water mixture type feed. The program objectives relative to combustion efficiency, combustor exit temperature, NOx emissions, carbon burnout, and slag rejection have been met. Work continues to reduce alkali, particulate, and SOx levels leaving the combustor. Parametric studies have been made that focus on the latter two problems. They indicate that faster, more thorough slag removal between the rich and lean stages is the path toward achieving lower emission of SOx, alkali, and particulates. New components have been added to the subscale combustor for this purpose.
Aerodynamics of Bluff Body Stabilized Confined Turbulent Premixed Flames
Authors: Pan J. C. , Vangsness M. D. , Ballal D. R. 
Published: March 2015

Detailed information on the influence of geometric and flow parameters on the structure and properties of recirculation zone in confined combusting flows is not available. In this paper, recirculation zone structure and turbulence properties of methane-air mixtures downstream of several conical flameholders were measured using LDA. These tests employed different blockage ratios (13% and 25%), cone angles (30, 45, 60, and 90 degrees), equivalence ratios (0.56, 0.65, 0.8, and 0.9), mean annular velocities (10, 15, and 20 m/s), and approach turbulence levels (2%, 17%, and 22%).
It was found that increasing the blockage ratio and cone angle affected the recirculation zone size and shape only slightly. Also, these parameters increased the shear stress and turbulent kinetic energy (TKE) moderately. Increasing the equivalence ratio or approach turbulence intensity produced a recirculation zone shape very similar to that found in the cold flow. TKE decreased due to turbulent dilatation produced by increased heat release. These observations are discussed from the viewpoint of their importance to practical design and combustion modeling.
Noise Control Technology With Reference to Natural Gas Compressor Stations Under the Aspect of Investment Costs
Authors: Schneider Manfred , Mann Jürgen 
Published: March 2015

For the conveyance and storage of natural gas, compressor stations are required where the installed power output varies mostly between 1 MW and 20 MW.
The noise control measures involved to meet the environmental noise immission regulations in Europe will be presented.
The most economical methods of noise control techniques are described particularly for the intake system and the exhaust system of gas turbines, the housing of such engines and for peripheral sound sources like gas coolers, oil coolers and the above ground piping.
Evaluation of NOx Mechanisms for Lean, Premixed Combustion
Authors: Corr Robert A. , Malte Philip C. , Marinov Nick M. 
Published: March 2015

The formation of the oxides of nitrogen, NOx, is examined through experiments and chemical kinetic modeling for lean, premixed combustion in a laboratory, atmospheric pressure, jet-stirred reactor. The experimental conditions are as follows: fuel-air equivalence ratio (ϕ) of 0.6, temperatures of 1460 to 1730 K, and reactor loadings of 20 to 150 kg/sec-m3-atm2, which correspond to reactor mean residence times of 11.4 to 1.8 milliseconds. Two fuels are examined: ethylene, because of its importance as a combustion intermediate, and methane, because of its importance as a component of natural gas. Besides the premixed operation, the reactor is also operated non-premixed. For both modes, the NOx increases with decreasing loading, from about 3–4 ppmv at the highest loading to about 11–21 ppmv at the lowest loading for the ethylene fuel. This increase in NOx occurs because a hot spot develops on centerline when the reactor is lightly loaded. Also for the lowest loading, the non-premixed mode produces about twice as much NOx as the premixed mode, i.e., about 21 versus 11 ppmv. At the other reactor loadings, however, because of the intense mixing, the NOx levels are only slightly elevated for the non-premixed mode compared to the premixed mode. Upon switching to methane fuel, the NOx decreases by about 25%.
The major finding of this study is that prompt NO is the predominant mechanism for the NOx formed. The other mechanisms considered are the Zeldovich and nitrous oxide mechanisms. Furthermore, the amount of NOx measured and modeled agrees almost exactly with the extrapolation of Fenimore’s (1971) original prompt NO data to the present conditions of ϕ = 0.6. Although Fenimore conducted his experiments with porous plate and Meker-type burners for 0.8 ≤ ϕ ≤ 1.7, our findings show that his results apply well to high-intensity, lean combustion. In the gas turbine literature, e.g. see Shaw (1974) and Toof (1985), Fenimore’s results are expressed as:(1)NO/(NO)equil=P1/2func(ϕ)It is func (ϕ) that extrapolates well to our conditions. This finding indicates that func (ϕ) applies to laboratory burners of widely different mixing intensity, i.e., from Fenimore’s burners with structured flame fronts to our high-intensity burner with dispersed reaction. In our opinion this finding strengthens the justification of using func (ϕ) for the prediction of NOx formation in practical combustors, including lean, premixed combustors.
Design and Evaluation of Silicon Nitride Turbocharger Rotors
Authors: Takama Kenichiro , Sasaki Syoji , Shimizu Tetsuji , Kamiya Nobuo 
Published: March 2015

Two types of silicon nitride ceramic rotors have been introduced into the Japanese market by Toyota Motor Corporation, which are named CT26 and CT12A, to improve engine acceleration response by the reduction in moment of inertia. In order to design a suitable blade shape for ceramic rotor ,the critical stress of blade was determined by the results obtained experimentally from correlating the fracture origin of over spin-tested rotors with centrifugal stress at fracture.
A suitable blade shape has been determined for the CT26 turbocharger rotor type, which is identical to the metal rotor except for the disc diameter of hub back face and the blade thickness. The CT12A type is of similar design to the CT26 type, all dimensions could reduce except for the inlet blade thickness, which is determined by foreign object damage ( FOD )resistance.
Discharge Coefficients of Cooling Holes With Radiused and Chamfered Inlets
Authors: Hay N. , Spencer A. 
Published: March 2015

The flow of cooling air within the internal passages of gas turbines is controlled and metered using orifices formed of holes in discs and casings. The effects of inlet radiusing and chamfering of these holes on the discharge coefficient forms the subject of this paper. Experimental results for a range of radiusing and chamfering ratios for holes of different length to diameter ratios are presented covering the range of pressure ratios of practical interest.
The results indicate that radiusing and chamfering are both beneficial in increasing the discharge coefficient. Increases of 10–30% are possible. Chamfered holes give the more desirable performance characteristics in addition to being easier to produce than radiused holes.
Self-Induced Flow in a Stepped Rotating Tube
Authors: Gilham S. , Ivey P. C. , Owen J. M. 
Published: March 2015

Self-induced flow occurs when a tube, open at one end and sealed at the other, is rotated about its central axis: fluid flows along the axis from the open end towards the sealed end and returns in a layer adjacent to the inner surface of the tube. This mechanism, which can occur under isothermal or nonisothermal conditions, is believed to be responsible for the so-called “hot-poker effect” that was observed during anti-icing tests on the nose bullet of an aeroengine.
This paper describes a combined theoretical and experimental study of self-induced flow. It is shown that, for the length-to-diameter (L/D) ratios and rotational Reynolds numbers associated with the anti-icing tubes of aeroengines, the laminar flow near the sealed end of the tube is similar to that of the so-called free disc. Swirl in the air outside the open end reduces the self-induced flow, but flow can reach the sealed end of a stepped tube which has either a sudden contraction or a sudden enlargement.
Performance Gains Derived From Water Injection in Regenerative, Indirect-Fired, Coal-Fueled Gas Turbines
Authors: Parsons Edward L. , Bechtel Thomas F. 
Published: March 2015

This paper discusses the performance benefits available from compressor discharge water injection in an indirect-fired gas turbine. The results of parametric performance studies are the main technical focus. The performance studies are part of the U.S. Department of Energy (DOE) Morgantown Energy Technology Center (METC) indirect-fired gas turbine program. The key technical approach is to develop a high-pressure, coal-fired ceramic heat exchanger to serve as the air heater.
A high-pressure coal-fired ceramic air heater is now under development in a DOE-sponsored program at Hague International. The goal of this program is to develop a heat exchanger suitable for turbine inlet temperatures from 1,100 to 1,260 °C. With a turbine inlet temperature in this range, coal-fired indirect systems have performance superior to direct-fired gas-fueled simple cycle systems. Using conservative assumptions, the coal-fired indirect cycle has calculated net plant efficiencies in the 32 to 37 percent range, on a higher heating value (HHV) basis, at typical pressure ratios and 1,260 °C (2,300 °F) turbine inlet temperature. Adding a steam bottoming cycle raises the net plant efficiency (NPE) to 44–48 percent HHV. Adding water injection raises the simple cycle efficiency to 41–43 percent HHV and the combined cycle efficiency to 47–54 percent HHV. These NPE’s compare favorably to the most advanced industrial direct-fired systems. For example, a natural gas-fired GE MS7001-F has published HHV efficiencies of 31.1 percent simple cycle and 46.1 percent combined cycle (Gas Turbine World, 1990).
A Predictive NOx Monitoring System for Gas Turbines
Authors: Hung W. S. Y. 
Published: March 2015

There is great interest in an alternative to the current rather expensive, high maintenance, weather sensitive, Continuous Emission Monitoring Systems (CEMS) or Continuous Emission Rate Monitoring Systems (CERMS) for stationary power sources. This is particularly relevant for smaller sources (<10 MW), as well as sites in remote areas and sites subject to extreme ambient conditions.
This paper describes the development of a predictive NOx monitoring system for industrial gas turbines. This type of system is currently being used as an alternative to in-stack CEMS or CERMS. This Predictive Emission Monitoring System (PEMS) utilizes a time-tested, proven mathematical model for NOx to verify the accuracy of a proven performance/emissions computer program which predicts NOx emissions from gas turbines based on measured ambient and turbine control parameters.
The technical background of this predictive NOx monitoring system and relevant experience are reviewed. The system design, including input and output, is described. A comparison of some technical issues between this predictive monitoring system and an actual typical in-stack NOx emission monitoring systems is also presented. A manual verification of the principle of this predictive system is reported.
A New 1.7MW Industrial Gas Turbine: The Ruston Hurricane
Authors: Sanders A. T. , Tothill M. H. , Wood G. R. 
Published: March 2015

The paper describes the design of a compact new 1.7MW (2300hp) single shaft industrial gas turbine and package, with high efficiency and exhaust temperature ideal for industrial congeneration applications.
These advantages are obtained with a high pressure ratio single stage centrifugal compressor, single high temperature combustor and two-stage axial flow turbine using only one row of cooled blades. The novel design features are described with the associated development testing. A typical installation is also described showing the potential for very high overall thermodynamic efficiency.
Measurements of Hot Combustor Turbulence Spectra
Authors: Moss R. W. , Oldfield M. L. G. 
Published: March 2015

This paper presents measurements of turbulence spectra at the exit plane of aircraft turbine combustors running at atmospheric exit pressure. These measurements are important in providing realistic input conditions for both experimental measurements and CFD predictions of first stage turbine heat transfer.
A transient technique in which a pitot probe was only briefly exposed to the flow allowed uncooled, flush mounted sub-miniature pressure transducers to be used for measuring the turbulence spectra of combustor exhaust gases at temperatures up to 1500 K.
Three different burner configurations were tested at fuel : air ratios from 0 to 0.02. It was found that the combustion process makes little difference to the turbulence power spectrum at wavenumbers between 100 and 1200 m−1. The effect of using two fuels with different burning rates ( paraffin and diesel ) was also studied.
A brief description of the probe calibration is included. The response was found to be a function of both frequency and wavenumber.
High-Temperature Gas Generator With Ceramic Components for Stationary Equipment Gas Turbine Unit
Authors: Shishov G. A. , Sudarev A. V. , Dubershtein V. N. , Tsurikov A. N. 
Published: March 2015

The paper gives description of the systematic analysis algorythm for multifactor matrix of partial solutions, namely, aerodynamic, thermodynamic, strength, processing, design, operation, and other aspects of designing the assemblies and parts of the gas generator with ceramic components. Interrelations between structural ceramics thermophysical and strength parameters, joint techniques (ceramic–ceramic and ceramic–metal components) has been determined at an optimum selection of turbine and compressor types and characteristics.
The complex of processing, design, and operation factors influencing the design of the components and assemblies of the gas generator has been studied.
Heat Transfer Characteristics of Rotating Ceramic Regenerators: Numerical Solution Using a Hybrid Finite Difference/Laplace Transform Scheme
Authors: Kawasaki Keiji , Matsuhisa Tadaaki , Sakai Itsuro , Hijikata Kunio 
Published: March 2015

A hybrid numerical method, combining finite differences with respect to space and a Laplace transform with respect to time, is proposed to determine the heat transfer in a rotary heat exchanger used as a rotating ceramic regenerator for automotive gas turbines. The temperature distributions of the core and of the working fluids are solved for given boundary and initial conditions of a rotary regenerator using this method. An advantage of the present method is that it can be applied when the core and the working fluids have dissimilar temperature distributions.
The temperature change in the ceramic honeycomb core was determined from start up to periodic steady state operation. The heat exchanger effectiveness was obtained for an extruded ceramic core used in automotive gas turbine applications.
A Propulsion Perspective of the Next Generation Supersonic Transport
Authors: Feig P. D. , Gilkey S. C. 
Published: March 2015

There is a growing, worldwide interest in a second generation supersonic transport aircraft. Air travel has tripled in the past 20 years to approximately 1000 billion revenue-passenger-miles per year. By the year 2010, air travel is anticipated to be 2 1/2 times that value, with long-range international travel the fastest growing segment. In order to become a reality, the second generation supersonic transport must be both environmentally acceptable and economically competitive with future subsonic aircraft.
Current research is now focused on addressing the major environmental issues of airport noise, engine emissions, and sonic boom. GE is studying a variety of engine and exhaust nozzle concepts and validating the emissions and acoustics technologies needed for this aircraft. In 1990, GE and P&W decided to work together to explore the feasibility of developing a second generation SST propulsion system. This paper provides an insight into our ongoing research and highlights the propulsion system’s influence on the viability of the second generation SST.