bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development and Turbine Engine Performance of Three Advanced Rhenium Containing Superalloys for Single Crystal and Directionally Solidified Blades and Vanes
Authors: Broomfield Robert W. , Ford David A. , Bhangu Harry K. , Thomas Malcolm C. , Frasier Donald J. , Burkholder Phil S. , Harris Ken , Erickson Gary L. , Wahl Jacqueline B. 
Published: December 2014

Turbine inlet temperatures over the next few years will approach 1650°C (3000°F) at maximum power for the latest large commercial turbo fan engines, resulting in high fuel efficiency and thrust levels approaching 445 kN (100,000 lbs). High reliability and durability must be intrinsically designed into these turbine engines to meet operating economic targets and ETOPS certification requirements.
This level of performance has been brought about by a combination of advances in air cooling for turbine blades and vanes, design technology for stresses and airflow, single crystal and directionally solidified casting process improvements and the development and use of rhenium (Re) containing high γ′ volume fraction nickel-base superalloys with advanced coatings, including full-airfoil ceramic thermal barrier coatings. Re additions to cast airfoil superalloys not only improve creep and thermo-mechanical fatigue strength but also environmental properties, including coating performance. Re dramatically slows down diffusion in these alloys at high operating temperatures.
A team approach has been used to develop a family of two nickel-base single crystal alloys (CMSX-4® containing 3% Re and CMSX®−10 containing 6% Re) and a directionally solidified, columnar grain nickel-base alloy (CM 186 LC® containing 3% Re) for a variety of turbine engine applications. A range of critical properties of these alloys is reviewed in relation to turbine component engineering performance through engine certification testing and service experience.
Industrial turbines are now commencing to use this aero developed turbine technology in both small and large frame units in addition to aero-derivative industrial engines. These applications are demanding, with high reliability required for turbine airfoils out to 25,000 hours, with perhaps greater than 50% of the time spent at maximum power. Combined cycle efficiencies of large frame industrial engines is scheduled to reach 60% in the U.S. ATS programme. Application experience to a total 1.3 million engine hours and 28,000 hours individual blade set service for CMSX-4 first stage turbine blades is reviewed for a small frame industrial engine.
Real-Time Fault Identification for Developmental Turbine Engine Testing
Authors: Malloy Donald J. , Chappell Mark A. , Biegl Csaba 
Published: December 2014

Hundreds of individual sensors produce an enormous amount of data during developmental turbine engine testing. The challenge is to ensure the validity of the data and to identify data and engine anomalies in a timely manner. An automated data validation, engine condition monitoring, and fault identification process that emulates typical engineering techniques has been developed for developmental engine testing.
An automated data validation and fault identification approach employing engine cycle-matching principles is described. Engine cycle-matching is automated by using an adaptive nonlinear component-level computer model capable of simulating both steady-state and transient engine operation. An automated model calibration process is also described. The model enables automation of traditional data validation, engine condition monitoring, and fault identification procedures. A distributed parallel computing approach enables the entire process to operate in realtime.
The result is a capability to detect data and engine anomalies in realtime during developmental engine testing. The approach is shown to be successful in detecting and identifying sensor anomalies as they occur and distinguishing these anomalies from variations in component and overall engine aerothermodynamic performance.
WR21 Water Wash Development Approach for the Intercooled Recuperated (ICR) Gas Turbine Engine
Authors: Janton Jay T. , Widdows Kevin 
Published: December 2014

The WR21 Intercooled Recuperated (ICR) Gas Turbine Engine is being developed as the prime power plant for future US and Foreign Navy ship applications. The development test program started in July 1994 and is still ongoing. One of the many challenges of the ICR design is the development of the compressors and intercooler (IC) wash system. The integration of the IC between the intermediate pressure compressor (IPC) and high pressure compressor (HPC) is unique to current US Navy applications and has introduced new design considerations from traditional wash development programs that must be addressed. Significant increase in wetted surface area of the heat exchanger (HX) matrix and the radial flow are two design aspects unique to the WR21.
This paper reviews the design of the WR21 engine and the challenges it offers to developing both crank and on-line compressor/IC wash systems. The baseline design of the water wash systems are discussed, in addition to the water wash test program and its integration into the overall WR2I development program. Details are also given of the off-engine wash delivery system and salt injection systems in place at the test site. Crank wash test results to date are also presented.
Viscous Flow Field Computations for a Transonic Axial-Flow Compressor Blade Using Different Turbulence Models
Authors: Lenke L. J. , Simon H. 
Published: December 2014

New blading concepts as used in modern transonic axial-flow compressors require improved calculation methods. Here the turbulence modelling has great influence. Therefore a quasi-three-dimensional compressor blade with subsonic inlet conditions is calculated using different turbulence models. A low-Reynolds number k-ϵ, the k-ω model and an explicit algebraic Reynolds stress model are considered in this investigation.
The results from these calculations in form of comparisons between the predicted isentropic Mach number distributions, profile losses and exit flow angles with experimental data are presented in this paper. They demonstrate the differences between the models in the prediction of the separation behavior of blade surface boundary layer especially which are introduced by shocks. For the high inlet Mach numbers the models differ also in the prediction of losses and deviation angles at design and off-design conditions.
Simultaneous Hot Desulfurization and Improved Filtration in Coal Utilization Processes Using Waste Material
Authors: Patel Parul C. , Zievers James F. , Eggerstedt Paul M. , Zievers Elizabeth C. 
Published: December 2014

Ceramic candle filtration is one of the few technologies for high temperature particulate removal which can meet both gas turbine manufacturer’s inlet particulate requirements and U.S. Clean Air Act requirements. Similarly, advances made in sorbent technology, especially metal oxide sorbents, have resulted in effective sulfur emissions mitigation. Current use of metal oxide sorbents, however, has focused on, regenerable formulations which have excellent sulfur affinity but high physical attrition, resulting in poor overall economics.
This paper suggests the use of spent metal oxide and calcium based materials for use in sulfur removal as an alternative to regenerable metal oxide sorbents. It becomes even more attractive when used in combination with ceramic candle filtration technology. When such sorbents are classified to a desired particle size and injected into a high temperature coal utilization process, such a “once-through” sorbent can effectively remove sulfur and simultaneously increase the permeability of dust collected at a downstream ceramic filter station, in a highly cost effective manner.
Gas Turbine Technology for Steel Mill Gas and Syngas Applications
Authors: Luessen H. Peter 
Published: December 2014

Recent market place activity over the past years has shown a renewed trend in using steel mill waste gas for combustion in gas turbines. To effectively use steel mill gas, as well as other industrial off gases and syngas from gasification, more than just the combustion process has to be considered. With steel mill gases some of the more critical areas involve gas clean up and compression, as well as integration with the steam system of the host industrial plant.
This paper will summarize some of the special considerations for applying a gas turbine/combined cycle power plant to a steel mill. Due to the similarities of the fuels, this paper will also discuss how this is common to other industrial gases applications. GE has substantial experience in combustion of low calorific fuels as well as industrial process gases and more recently steel mill gases.
A Mechanical Start System for U. S. Navy Destroyer Generator Sets
Authors: Overton Leonard L. , Masincup William E. , Halsey Jack E. 
Published: December 2014

A mechanical start system has been developed to start the Ship’s Service Gas Turbine Generators (SSGTG) on board U.S. naval destroyers. The current starting system uses either stored high pressure air or bleed air from another running turbine. The U.S. Navy has reviewed the high pressure air system and found it to be a costly system for both ship construction and maintenance. As a result, the Navy is requiring an alternative starting method that will replace high pressure air. It should be noted that any alternative that introduces compressed air to start the SSGTG depends on the start air regulating assembly and the pneumatic starter.
The Redundant Independent Mechanical Start System (RIMSS) consists of an Allison Model 250 turboshaft engine mounted above the SSGTG main reduction gearbox. The turboshaft power take off is connected to the pinion shaft of the reduction gearbox by means of a parallel shaft auxiliary transfer gearbox. The transfer gearbox connection to the reduction gearbox replaces the pneumatic starter adapter pad but provides a means to also connect the pneumatic starter. As a result, the pinion shaft can be driven either pneumatically by the air turbine or mechanically by the Model 250 engine. This provides an alternative starting mode which is totally independent of the present means of starting. This will increase the reliability and availability of the SSGTG since it can still be started even if the pressure regulator or the pneumatic starter is not functional. This system has undergone testing at the Naval Surface Warfare Center Carderock Division facility in Philadelphia.
Laser Anemometer Measurements of the Flow Field in a 4:1 Pressure Ratio Centrifugal Impeller
Authors: Skoch G. J. , Prahst P. S. , Wernet M. P. , Wood J. R. , Strazisar A. J. 
Published: December 2014

A laser-doppler anemometer was used to obtain flow-field velocity measurements in a 4:1 pressure ratio, 4.54 kg/s (10 lbm/s), centrifugal impeller, with splitter blades and backsweep, which was configured with a vaneless diffuser. Measured through-flow velocities are reported for ten quasi-orthogonal survey planes at locations ranging from 1% to 99% of main blade chord. Measured through-flow velocities are compared to those predicted by a 3-D viscous steady flow analysis (Dawes) code.
The measurements show the development and progression through the impeller and vaneless diffuser of a through-flow velocity deficit which results from the tip clearance flow and accumulation of low momentum fluid centrifuged from the blade and hub surfaces. Flow traces from the CFD analysis show the origin of this deficit which begins to grow in the inlet region of the impeller where it is first detected near the suction surface side of the passage. It then moves toward the pressure side of the channel, due to the movement of tip clearance flow across the impeller passage, where it is cut by the splitter blade leading edge. As blade loading increases toward the rear of the channel the deficit region is driven back toward the suction surface by the cross-passage pressure gradient. There is no evidence of a large wake region that might result from flow separation and the impeller efficiency is relatively high. The flow field in this impeller is quite similar to that documented previously by NASA Lewis in a large low-speed backswept impeller.
Operation of a Primary Surface Recuperator on a Liquid Fueled Combustion System
Authors: Stephenson Michael D. , Ward Mike E. , Holman Len 
Published: December 2014

Gas turbine recuperators have been put in operation in a number of applications, although the experience on liquid fuel has been minimal. Possibilities of liquid fouling of the compact surfaces of recuperators has been a significant concern.
A extended duration fouling test of a compact recuperator was conducted using a simulated gas turbine exhaust stream from a commercial dry low NOx atmospheric combustion system. This combustion system has consistently demonstrated operation with negligible smoke and low NOx emissions. The low smoke significantly reduces the likelihood of fouling of downstream equipment. Fouling of the recuperator was virtually undetectable after 1000 hours of operation. Visual inspection of the recuperator core confirmed there was no soot buildup of any kind.
High Temperature Braze Repair for Compressor Blades
Authors: van Esch Hans , Herren Ernst 
Published: December 2014

This summary describes the repair and refurbishment process development for a set of compressor blades that suffered from heavy pitting corrosion. The objective was to restore the surface of the corroded blades and regain fatigue strength, while maintaining the proper airfoil profile.
Metallurgical evaluation during the development and refurbishment indicated where improvements were needed and later on controlled the progress of the repair. Mechanical tests, such as fatigue and hardness, were performed to ensure that mechanical property criteria were met following the complete refurbishment of the blades.
The resulting repair scheme is generic and can be used on most types of gas turbine compressor blades.
Heat Transfer Coefficient Distributions for the Convective Cooling of Non-Cylindrical Geometries in Crossflow Using Extended Surfaces
Authors: Neely Andrew J. , Ireland Peter T. , Harper Les R. 
Published: December 2014

An experimental investigation of the performance of extended fin surfaces for the forced convective cooling of a range of engine component geometries in crossflow is reported. The experiments were undertaken to measure the surface heat transfer coefficient distributions of external finning around non-cylindrical geometries for use in aviation gas turbines in which the cooling performance/mass ratio must be maximised. The geometries examined were a box (square with rounded corners), a flute (rectangle with circular ends) and a 30° wedge. These models were sized to have equivalent cross sectional area to allow a direct comparison of performance. Perspex models coated with thermochromic liquid crystal were tested at a range of Reynolds numbers in a heat transfer wind tunnel in which a step change in flow temperature was used to measure the transient thermal behaviour of the fins. This technique enables the full surface mapping of local heat transfer coefficients on the surface of the fins.
These measurements are compared with those for the equivalent smooth geometries and also with empirical calculations from the literature where available. A comparison with previous cylindrical measurements is also made. Knowledge of the distributions of local heat transfer coefficients enables the optimisation of the geometry through strategies such as baffling of the fins. Some examples of these strategies have been implemented and the results are reported.
The finned geometries are seen to outperform the unfinned geometries (by factors greater than 3) though by factors less than simply the increase in area. The enhancement in h results because the increased surface area of the fins more than outweighs the decrease in local h on the fin surface as compared to the smooth geometries.
A Shock Loss Model for Supersonic Compressor Cascades
Authors: Bloch Gregory S. , Copenhaver William W. , O’Brien Walter F. 
Published: December 2014

Loss models used in compression system performance prediction codes are often developed from the study of two-dimensional cascades. In this paper, compressible fluid mechanics has been applied to the changes in shock geometry that are known to occur with back pressure for unstarted operation of supersonic compressor cascades. This physics-based engineering shock loss model is applicable to cascades with arbitrary airfoil shapes.
Predictions from the present method have been compared to measurements and Navier-Stokes analyses of the L030-4 and L030-6 cascades, and very good agreement was demonstrated for unstarted operation. A clear improvement has been demonstrated over previously published shock loss models for unstarted operation, both in the accuracy of the predictions and in the range of applicability.
The dramatic increase in overall loss with increasing inlet flow angle is shown to be primarily the result of increased shock loss, and much of this increase is caused by the detached bow shock. For a given Mach number, the viscous profile loss is nearly constant over the entire unstarted operating range of the cascade, unless a shock-induced boundary layer separation occurs near stall. Shock loss is much more sensitive to inlet Mach number than is viscous profile loss.
Effects of Non-Axisymmetric Tip Clearance on Axial Compressor Performance and Stability
Authors: Graf M. B. , Wong T. S. , Greitzer E. M. , Marble F. E. , Tan C. S. , Shin H.-W. , Wisler D. C. 
Published: December 2014

The effects of circumferentially non-uniform lip clearance on axial compressor performance and stability have been investigated experimentally and analytically. A theoretical model for compressor behavior with non-axisymmetric tip clearance has been developed and used to design a series of first-of-a-kind experiments on a four-stage, low speed compressor. The experiments and computational results together show clearly the central physical features and controlling parameters of compressor response to non-axisymmetric lip clearance.
It was found that the loss in stall margin was more severe than that estimated based on average clearance. The stall point was, in fact, closer to that obtained with uniform clearance at the maximum clearance level. The circumferential length scale of the tip clearance (and accompanying flow asymmetry) was an important factor in determining the stall margin reduction. For the same average clearance, the loss in peak pressure rise was 50% higher for an asymmetry with fundamental wavelength equal to the compressor circumference than with wavelength equal to one-half the circumference. The clearance asymmetry had much less of an effect on peak efficiency; the measured maximum efficiency decrease obtained was less than 0.4 percent compared to the 8% decrease in peak pressure rise due to the asymmetric clearance. The efficiency penalty due to non-axisymmetric tip clearance was thus close to that obtained with a uniform clearance at the circumferentially-averaged level.
The theoretical model accurately captured the decreases in both steady-state pressure rise and stable operating range which are associated with clearance asymmetry. It also gave a good description of the observed trends of (i) increasing velocity asymmetry with decreasing compressor flow, and (ii) decreasing effect of clearance asymmetry with decreasing dominant wavelength of the clearance distribution. The time resolved data showed that the spatial structure of the pre-stall propagating disturbances in the compressor annulus was well represented and that the stability limiting process could be linked to the unsteady structure of these disturbance modes.
The model was also utilized for parametric studies to define how compressor performance and stability is affected by the circumferential distribution of clearance, steady-state compressor pressure-rise characteristic, and system dynamic parameters. Sensitivity to clearance asymmetry was found to fall off strongly with the (asymmetry-related) reduced frequency and to increase with peak pressure rise and increasing curvature of the characteristic near the peak.
Industrial Gas Turbine Uprates: Tips, Tricks and Traps
Authors: Ragland T. L. 
Published: December 2014

After industrial gas turbines have been in production for some amount of time, there is often an opportunity to improve or “uprate” the engine’s output power or cycle efficiency or both. In most cases, the manufacturer would like to provide these uprates without compromising the proven reliability and durability of the product. Further, the manufacturer would like the development of this “Uprate” to be low cost, low risk and result in an improvement in “customer value” over that of the original design. This paper describes several options available for enhancing the performance of an existing industrial gas turbine engine and discusses the implications for each option. Advantages and disadvantages of each option are given along with considerations that should be taken into account in selecting one option over another.
Specific options discussed include dimensional scaling, improving component efficiencies, increasing massflow, compressor zero staging, increasing firing temperature (thermal uprate), adding a recuperator, increasing cycle pressure ratio, and converting to a single shaft design. The implications on output power, cycle efficiency, off-design performance engine life or time between overhaul (TBO), engine cost, development time and cost, auxiliary requirements and product support issues are discussed. Several examples are provided where these options have been successfully implemented in industrial gas turbine engines.
Design of a High Efficiency Industrial Turbine Blade Utilizing Third Generation Single Crystal Alloy CMSX®-10
Authors: Fitzpatrick Michael D. , Brentnall William D. , Meier Andrew , Erickson Gary L. , DeBoer Gary 
Published: December 2014

Future advancements in the efficiency and reliability of Industrial Gas Turbines (IGT) will be closely tied to the application of advanced materials, together with increasingly sophisticated turbine hot section designs. An example of this trend is illustrated by the recent design of a first stage blade component for an advanced IGT concept utilizing the third generation single crystal superalloy CMSX-10. It is anticipated that alloy CMSX-10 will permit the use of increased turbine firing temperatures with reduced cooling flows compared to previous recuperated turbine designs, while maintaining acceptable blade durability and life-cycle cost.
This paper discusses some of the design/materials analyses and cost studies performed on the blade, which ultimately led to the consideration of alloy CMSX-10 for the IGT application. The solid modeling and finite element blade design methods which allowed the incorporation of state-of-the-art cooling technology and aerodynamics are described. Alloy CMSX-10 characteristics, particularly mechanical properties and microstructural stability considerations, are discussed. Additionally, the results of a recent casting demonstration in an IGT blade configuration are presented. Finally, future tasks supporting the application of the alloy are outlined, such as coatings development efforts and the DOE/ORNL sponsored Land Based Turbine Casting Initiative; activities sponsored through a cooperative agreement with the United States Department of Energy within the Advanced Turbine System (ATS) Program.