bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Aspects of Deposition/Corrosion From Coal-Water Fuels Under Gas Turbine Conditions
Authors: Wenglarz Richard A. , Fox Ralph G. 
Published: March 2015

A staged, subscale turbine combustor based on a promising rich-quench-lean combustor approach to reduce NOX emissions was used to evaluate deposition, erosion, and corrosion (DEC) from coal-water fuels (CWF). This combustor was operated with three CWF at conditions of a recuperated turbine. Specimens were exposed in two test sections at temperature conditions of the first stator vanes and first rotor blades of the recuperated turbine. Resulting deposits were chemically analyzed. Deposit covered segments of specimens were placed in a furnace to extend their exposure to the potentially corrosive deposits.
The deposits produced at higher temperature first stator conditions differed significantly from those produced at lower temperature first rotor conditions. The rates of formation of the higher temperature deposits were high and the deposit chemistries were similar to the coal ash chemistry. The rates of formation of the lower temperature deposits were one to two orders of magnitude less and deposit chemistries were not the same as the coal ash chemistry. Some corrosion of a CoCrAlY coating was detected after a few hours of exposure in the DEC tests. Corrosion penetration up to one-half of the coating thickness was observed after an additional 460 hr furnace exposure. Much more testing is needed to explore whether the deposition and corrosion produced by the fuels evaluated are typical of this fuel form and to assess benefits of alternate turbine protection measures.
Some Aerodynamic Aspects of Engine Secondary Air Systems
Authors: Zimmermann H. 
Published: March 2015

Internal cooling air systems of turbomachines contain various fluid flow components, i.e. rotating holes, tapping configurations, coverplates, labyrinth seals etc., for which only the basic aerodynamics are known. Numerical calculations for these elements are carried out and compared with test results showing fair agreement in general.
For most of the components of internal air systems there is a serious lack of test data. It is shown that the situation can be relieved by applying numerical methods, which should also be used to improve and extend the empirical correlations in the air systems computer programs.
Parametric Analysis of the Kalina Cycle
Authors: Marston Charles H. 
Published: March 2015

The Kalina Cycle utilizes a mixture of ammonia and water as the working fluid in a vapor power cycle. When the liquid mixture is heated the more volatile ammonia tends to vaporize first and at a lower temperature than does pure water. This property of ammonia-water mixtures makes possible a better match to the enthalpy-temperature curve of a hot gas heat source such as a gas turbine exhaust and also permits circulation of fluids of different composition in different parts of the cycle. Taking advantage of the latter feature, condensation (absorption) can be done at slightly above atmospheric pressure with a low concentration of ammonia, while heat input is at a higher concentration for optimum cycle performance.
Computer models have been used to optimize a simplified form of the cycle and to compare results for a more complex version proposed by El-Sayed and Tribus. A method of balancing the cycle was developed and key parameters for optimizing the cycle identified.
Aerodynamic and Heat Transfer Measurements on Blading for a High Rim-Speed Transonic Turbine
Authors: Kingcombe R. C. , Harasgama S. P. , Leversuch N. P. , Wedlake E. T. 
Published: March 2015

A high rim speed turbine, incorporating some 3-D features has been designed and tested at RAE Pyestock. There has been cold flow turbine testing, with overall performance measurements, rotor exit traversing as well as surface static pressure measurements on the vane and rotor. The vane has also been tested in annular cascade on the Isentropic Light Piston Cascade giving surface heat transfer measurements on the vanes and endwalls as well as aerodynamic information.
The data have been used to compare with design predictions and the reasons for the differences observed, particularly on the rotor blade, are explored.
Repair Standards for Aero and Industrial Turbine Blades
Authors: Liburdi J. , Lowden P. 
Published: March 2015

The maintenance of aero and industrial engines requires components to be refurbished to a level appropriate to their service and overhaul requirements.
In some cases, the refurbishment of jet engine blades requires only minor tip restoration, whereas, in other cases, complete remanufacturing and heat treating are necessary.
This paper examines the various levels of repair performed on aero and industrial blades, as well as reviewing the influence of these repairs on the reliability and the remaining life of these parts.
It is essential that turbine operators recognize that repairs can vary, not only in extent, but in quality and reliability. Therefore, they must specify the appropriate standard of repair and re-certification required for their engines.
Experimental Study of a Reverse Flow Combustor: Influence of Primary Holes on Combustor Efficiency
Authors: Cadiou Anne , Grienche Guy 
Published: March 2015

The primary zone of the reverse flow combustors for helicopters tested at ONERA is fed with air from primary holes, multiples holes for the wall cooling and prevaporiser tubes.
The effect of the primary holes on the combustor performances has been studied.
Gas sampling inside the combustor has been achieved in order to understand the flow mechanisms with and without primary holes. The differences observed on the 2 configurations are not significant. Air from the prevaporiser tubes and from the wall cooling is sufficient for the air feeding of the primary zone.
Dry Low NOx Combustion Development for Electric Utility Gas Turbine Applications: A Status Report
Authors: Angello Leonard , Lowe Phillip 
Published: March 2015

National standards for NOx control for gas turbines are being evaluated and modified throughout the world. These standards are often supplemented by local or site specific emission limits. The numeric value of any emission limit is influenced by both the local environmental conditions, and, importantly, by the actual NOx removal capacity of the specific technologies that can be applied to the processes and equipment that will be governed by the emission standards. That is, emission limits can not be so restrictive that there is no technology available that can be applied to meet the permit condition. However, as new technologies are developed to meet the ever increasingly restrictive emission limitations, they become the standard by which the next round of emission limit setting is guided.
Current NOx control technologies for gas turbine applications employ fuel switching to a low nitrogen content fuel, wet combustion control (steam or water injection into the combustor), or exhaust gas treatment (selective catalytic reduction technology) or combinations of those controls.
Recently, dry combustion controls have been, or are being, developed by the gas turbine manufacturers, and catalytic combustion control processes are being researched. This paper presents a brief overview of the national NOx emission requirements of Europe, Japan, and the United States. A discussion of the new dry, low NOx controls presently emerging in the electric utility, gas turbine market are then reviewed, with an emphasis on the commercial applications and typical operating results that have been experienced.
In this paper, all NOx values are referenced to dry, 15% oxygen exhaust conditions unless otherwise stated. The units are volumetric, in parts per million (ppm), unless otherwise stated.
Holographic Flow Visualisation of Turbofan By-Pass and Core Nozzle Streams
Authors: Bryanston-Cross P. J. , Harris A. E. , Bakshi S. 
Published: March 2015

This investigation has been made to show the suitability of holography as an optical flow diagnostic for turbofan nozzle flow structures. In this case a static 1/25th scale model of a powered turbofan nacelle has been used for nacelle/wing integration studies and evaluated using a holographic technique.
The holograms made show the core jet and the by-pass flow as it emerges from the nacelle nozzle system. They also show evidence of structural vibration at the by-pass nozzle wall.
A comparison has also been made with alternative non-invasive diagnostic techniques.
Surface Roughness Measurements on Gas Turbine Blades
Authors: Taylor Robert P. 
Published: March 2015

Results are presented from profilometer measurements of the surface roughness on inservice turbine engine blades from F-100 and TF-39 aeroengines. On each blade, one roughness profile is taken in the region of the leading edge, the mid-chord and the trailing edge on both the pressure and suction sides for a total of 6 profiles. Thirty 1st stage turbine blades are measured from each engine. Statistical computations are performed on these profiles and the root mean square height, skewness and kurtosis of the roughness height distribution are presented along with the correlation length of the autocorrelation function.
The purpose of this work is to provide insight into the nature of surface roughness characteristics of inservice turbine blades which can be used in the development of scaled laboratory experiments of boundary layer flow and heat transfer on turbine engine blades.
Prediction of Heat Transfer in a Rotating Cavity With a Radial Outflow
Authors: Ong C. L. , Owen J. M. 
Published: March 2015

Solutions of the differential boundary-layer equations, using the Keller-box scheme and the Cebeci-Smith eddy-viscosity model for turbulent flow, have been used to predict the Nusselt numbers on the discs of a heated rotating cavity with a radial outflow of cooling air.
Computed Nusselt numbers were in satisfactory agreement with analytical solutions of the elliptic equations for laminar flow and with solutions of the integral equations for turbulent flow. For a wide range of flow rates, rotational speeds and disc-temperature profiles, the computed Nusselt numbers were in mainly good agreement with measurements obtained from an air-cooled rotating cavity. It is concluded that the boundary-layer equations should provide solutions accurate enough for application to air-cooled gas-turbine discs.
Annular Cascade Study of Low Back-Pressure Supersonic Fan Blade Flutter
Authors: Kobayashi Hiroshi 
Published: March 2015

Low back-pressure supersonic fan blade flutter in the torsional mode was examined using a controlled-oscillating annular cascade test facility. Precise data of unsteady aerodynamic forces generated by shock wave movement due to blade oscillation and the previously measured data of chordwise distributions of unsteady aerodynamic forces acting, on an oscillating blade were joined, and then the nature of cascade flutter was evaluated. These unsteady aerodynamic forces were measured by direct and indirect pressure measuring methods. Our experiments covered a range of reduced frequencies based on a semi-chord from 0.0375 to 0.547, 6 interblade phase angles and inlet flow velocities from subsonic to supersonic flow.
The occurrence of unstalled cascade flutter in relation to reduced frequency, interblade phase angle and inlet flow velocity was clarified including the role of unsteady aerodynamic blade surface forces on flutter. Reduced frequency of the flutter boundary increased greatly when the blade suction surface flow became transonic flow. Interblade phase angles which caused flutter were in the range from 40° to 160° for flow fields ranging from high subsonic to supersonic. Shock wave movement due to blade oscillation generated markedly large unsteady aerodynamic forces which stimulated blade oscillation.
Through Flow Theory for Nonaxisymmetric Turbomachinery Flow: Part I — Formulation
Authors: Dring Robert P. , Oates Gordon C. 
Published: March 2015

Through flow theory has been limited in its applicability and in its accuracy by the fact that it has not historically been cast in a form which can account for the nonaxisymmetries that naturally arise in turbomachinery flow due to the presence of finite numbers of rotor and stator airfoils. The attempt to circumvent this limitation by the introduction of an aerodynamic blockage factor has been demonstrated in earlier work to produce fundamental inconsistencies in the calculation which lead to significant errors in the regions of the flow where the nonaxisymmetries are severe. The formulation in Part I of the present work is a derivation of a system of through flow equations for nonaxisymmetric flow.
A benchmark data base is used in Part II to provide input to the calculation and to help identify the dominant terms. It is demonstrated that the dominant effect of nonaxisymmetry is contained in two terms that relate the total pressure of the averaged flow to the mass averaged total pressure. It is also demonstrated that the present formulation produces a result which is more accurate than that obtained with the historical blockage-based formulation.
A Computer Aided Method for the Design of Centrifugal Impellers Using Optimization Techniques
Authors: Al-Zubaidy Sarim Jawad 
Published: March 2015

The paper proposes a design method which may be used to evaluate the impeller detailed geometry for a prescribed mean stream velocity distribution. The analysis makes extensive use of numerical optimization, firstly in the step by step channel geometry calculation, and secondly in controlling the manner in which the relative velocity components are permitted to vary along the mean streamline for the condition of minimum entropy generation along the flow path. It should be mentioned that the components of the relative velocity were not allowed to take arbitrary values. The variation of the radial, axial and tangential components was governed in such a way that the prescribed diffusion schedule is satisfied at every point.
An example impeller is shown, which was designed using the proposed method. The general configuration of the example design shows it to be not difficult to manufacture.
Influences of Splitter Blades on the Centrifugal Fan Performances
Authors: Gui Lichuan , Gu Chuangang , Chang Hongshou 
Published: March 2015

Centrifugal fan and compressors with splitter blades are widely utilized in engineering practices. A detail investigation of the influences of splitter blades on a forward-curved centrifugal fan performances is presented in the paper. The study includes two parts: experiment and numerical calculation. The experiments were produced in a specific impeller with adjustable splitter blades in order to get the performances in different conditions. The internal flow field in the impeller was calculated by means of FEASM (Finite Element Approximate Solution Method, Gu, 1984).
The experimental result show that changing the circumferential positions of the splitter blades has a noticeble influence on the fan performance, the incidence of splitter blades also has a certain effect on it, and properly lengthened splitter blades can raise the total pressure coefficient.
The velocity and load distributions on the blade surfaces calculated can be used to analyse the phenomena above satisfactorily.
Condition Monitoring of Aeroderivative Gas Turbines
Authors: Boyce M. P. , Meher-Homji Cyrus B. , Wooldridge Byron 
Published: March 2015

Aeroderivative gas turbines play a critically important role in the gas distribution and cogeneration industry. The need for maintaining high efficiency and availability has created the need for condition monitoring systems. This paper covers aspects relating to online condition monitoring techniques.
The subject matter of this paper applies to all aeroderivative gas turbines. Owners and operators of these machines can reduce operating costs and enhance availability and performance by paying close attention to the operating condition of their equipment. By doing so, performance tuning for optimum operating costs can be accomplished. Likewise, preventive maintenance efforts can be enhanced.
Blade Sweep for Low-Speed Axial Fans
Authors: Wright Terry , Simmons William E. 
Published: March 2015

The available literature on aerodynamic and acoustic properties of axial fans with swept blades is presented and discussed with particular emphasis on noise mechanisms and the influence of high-intensity inlet turbulence on “excess” noise. The acoustic theory of Kerschen and Envia for swept cascades is applied to the problem of axial fan design. These results are compared to available data and a provisional model for specifying sweep angles is presented. The aerodynamic performance theory for swept-bladed rotors of Smith and Yeh is adapted for use in designing low speed axial fans.
Three prototype fans were designed using the resultant computer codes. One is a baseline fan with blade stacking lines radially oriented, and two are fans having swept blades of increasingly greater forward sweep. Aerodynamic testing shows that performance of the fans lie within a band width of about ± two percent of volume flow rate and pressure rise predictions in the region of design performance, effectively validating the design procedure for selection of the blading parameters.
Noise testing of the fans was carried out and the results show an average noise reduction for the swept-bladed fans of about 7 dBA overall, and a reduction of pure tone noise at blade-pass frequency of about 10 dB compared to the zero-sweep baseline model in close agreement with the theory of Kerschen and Envia.
A Comparison Between the Design Point and Near Stall Performance of an Axial Compressor
Authors: McDougall N. M. 
Published: March 2015

Detailed measurements have been made within an axial compressor operating both at design point and near stall. Rotor tip clearance was found to control the performance of the machine by influencing the flow within the rotor blade passages. This was not found to be the case in the stator blade row, where hub clearance was introduced beneath the blade tips. Although the passage flow was observed to be altered dramatically, no significant changes were apparent in the overall pressure rise or stall point.
Small tip clearances in the rotor blade row resulted in the formation of corner separations at the hub, where the blade loading was highest. More representative clearances resulted in blockage at the tip due to the increased tip clearance flow. The effects which have been observed emphasize both the three dimensional nature of the flow within compressor blade passages, and the importance of the flow in the endwall regions in determining the overall compressor performance.
Optimum Weight Design of a Rotor Bearing System With Dynamic Behavior Constraints
Authors: Shiau Ting Nung , Hwang Jon Li 
Published: March 2015

An efficient design algorithm for optimum weight design of a rotor bearing system with dynamic behavior constraints is investigated. The constraints include the restrictions on stresses, unbalance response, and/or critical speeds. The system dynamic behaviors are analyzed by the finite element method. And the exterior penalty function method is used as the optimization technique to minimize the system weight.
The system design variables are the cross-sectional areas of the shaft and the stiffnesses of the bearings. The sensitivity analysis of the system parameters is also investigated. The example of a single spool rotor bearing system is employeed to demonstrate the merits of the design algorithm with different combination of dynamic behavior constraints. At the optimum stage, it is shown that the weight of rotor system can be significantly reduced. Moreover, the optimum design weights are quite difference for various combinations of dynamic behavior constraints.
Ten Years’ Operating History of a Large Gas Turbine/Recompression Train
Authors: Conquergood C. Peter , Blauser Dave , Willbourn Peter 
Published: March 2015

In 1978, Shell Canada Limited commissioned a large aero-derivative gas turbine driven compressor unit in its Waterton Straddle Plant. This unspared unit provides the primary recompression service in the “Deep Cut” ethane extraction facility. Significant operating features of this unit include flat rating and three stages of waste heat recovery from the turbine exhaust.
Throughout its history, this unit has demonstrated over 99% reliability and has operated for long periods without significant maintenance. All routine turbine maintenance has been accomplished on-site.
This paper describes the features of the installation, the operating and maintenance philosophy, and the experience obtained from ten years’ service, thus providing the reader with insight in regard to features and practices which can provide for a successful installation.
Preliminary Performance Estimates for a GE Steam Injected LM1600 Gas Turbine
Authors: Thames J. M. , Coleman R. P. 
Published: March 2015

Preliminary performance modeling and conceptual designs have been completed for the addition of a steam injection system to a natural gas fired General Electric (GE) LM1600 gas turbine. The steam injected LM1600 gas turbine (STIG™ system) is an attractive size, 13 to 17 mw, for both cogeneration and small power applications. The STIG™ system offers numerous benefits including 1) increased power output in a compact single engine system, 2) improved efficiency, 3) reduced exhaust emissions, 4) steam-to-power flexibility, and 5) attractive system economics.
This paper describes the LM1600 STIGTM system conceptual design, performance estimates and projected emissions.
The Influence of Air/Fuel Ratio and Swirl Number on the Combustion Characteristics of a Model Combustor
Authors: Bicen A. F. , Tse D. G. N. , Whitelaw J. H. 
Published: March 2015

Combustion characteristics of a model can-type combustor are reported for air/fuel ratios encompassing take-off and ground-idle conditions and for two swirlers with gaseous fuel and at atmospheric pressure. Temperatures were obtained with fine-wire thermocouples, and concentrations of UHC, H2, CO, CO2, O2 sampled through a water-cooled probe with a flame ionization detector, a gas chromotograph and infrared and paramagnetic analyzers.
The results indicate combustion efficiencies greater than 97%. For the air/fuel ratio corresponding to that of take-off, 45% of the mass flow of the primary jets turned upstream after impingement, combustion occurred in the wakes of the swirler and of the primary jets resulting in a pattern factor of 0.46. At ground-idle condition, 58% of the primary jet flow turned upstream reducing the pattern factor to 0.43. An 18% reduction in the swirl number at the ground-idle condition led to a pattern factor to 0.35 and, for takeoff, to a pattern factor of around 0.37 with combustion occurred mainly in the intermediate zone.
Vibration Analysis of Cracked Turbine and Compressor Blades
Authors: Ostachowicz W. , Krawczuk M. 
Published: March 2015

The object of the paper is to present a method of vibration analysis of cracked turbine and compressor blades. A transverse crack in a blade introduces local flexibility, which changes dynamic characteristics of a structure.
The assumption of the open and closed crack leads to a model with point finite elements which are introduced to the crack model. The blade is modelled by spatial finite elements.
The method described in the paper can be used for the study of the effects of crack locations and sizes on the vibrational behaviour of the structure. The analysis is provided along with an algorithm and an example of calculations.
The authors have compared the calculation results of the beam model with a crack (regardless of friction in the crack) with the investigation results of paper [2] and have secceeded in obtaining a high compatibility of the results. Hovever, the comparison of the results relevant to the model taking into account friction in the crack was impossible due to inavailabity of similar papers in literature.