bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Kalina Cycle Designs With Modifications Including a Distillation Column
Authors: Glasare Karin B. , Olsson Eva K. , von Spakovsky Michael R. , Svedberg Gunnar 
Published: February 2015

It has been shown in a number of studies that the Kalina cycle can have considerably higher efficiencies than the Rankine cycle. An especially advantageous application is as a bottoming cycle to a gas turbine. In this paper a gas turbine topping cycle has been assumed.
Three different configurations of the Kalina bottoming cycle have been examined and compared. One is an original cycle (El-Sayed and Tribus, 1985) with a flash separator. In another configuration, a second feedwater heater is added and in a third a distillation column instead of a flash separator is used. The stages of the column are heated by exchanging heat with two different streams in the Kalina distillation condensation subsystem.
For each configuration, the different compositions in the cycle have been varied. The First Law efficiency and the exergetic efficiency have been calculated as well as the rate of exergy loss in each unit. The results show that the cases with the best performance of each of the three configurations differ very little in efficiency. The original cycle has the highest efficiency for the conditions studied.
Restoration of Thinned Airfoils by Application of Physical Vapor Deposition Coating
Authors: Rose Daniel P. , Price George D. , Saenz Joe A. , Lawton Paul F. 
Published: February 2015

The GTCP331-200/250 auxiliary power unit (APU) is used to provide electrical power and compressed air for commercial aircraft, including the Boeing 757 and 767, and Airbus A310. The turbine section of this engine is a three stage axial flow configuration. Due to the combined effect of oxidation and erosion, the useful life of the first stage turbine blade may be limited by loss of material on the airfoil. The effect of material loss is reduction of the airfoil thickness and chord length.
This paper discusses a repair that restores the airfoil dimensions by buildup with a physical vapor deposition coating. The repair process includes incoming dimensional inspection of the airfoil, physical vapor deposition with tapered thickness to restore airfoil dimensions, and post deposition processing. The evaluation includes airfoil dimensional inspection, metallographic verification of coating integrity, and finite element modeling to illustrate the effect of material buildup on different locations of the airfoil.
Gas Turbine Operating in Combined and Regenerative Cycles Using Liquid Metal Heat Exchangers
Authors: Perkavec M. A. 
Published: February 2015

Liquid metal technology for heat transfer was developed for use in nuclear power stations. Applied to a gas turbine regenerative cycle plant, it makes high heat exchange rates in the regenerator, and low pressure losses as well on the air side as on the exhaust side economically possible. Its application permits combined cycle as well as regenerative cycle operation of the same gas turbine. Mixed operation in any ratio is also easily accomplished, so that the ratio of heat and electricity produced by the gas turbine plant is variable within a wide range.
This paper presents the results of thermodynamic calculations for such plants and describes the optimization of design parameters. Influences of the individual parameters of the regenerative cycle on the power output and efficiency of the plant are examined, and the reasonable limits for this application are outlined.
The advantages of applying liquid metal technology to gas turbines, such as a virtually pressureless liquid metal system, flexible operation, and separate optimization of the heat exchange coefficients for the air and exhaust flows are discussed.
Reference is also made to emissions, which are more complicated than those for combined or regenerative cycles because the plant is operated in both modes.
Toward Modeling the Concurrent Design of Aircraft Engine Turbines
Authors: Lee Hauhua , Goel Sanjay , Tong Siu S. , Gregory Brent , Hunter Scott 
Published: February 2015

This paper describes our approach and experiences in constructing the Turbine Auto–Designer (TAD), an automated concurrent design system for aircraft engine turbines. In TAD, the design process is modeled based on the computer programs of a representative design system. It integrates three domains of the manual design process: preliminary design, detailed aerodynamic design, and detailed mechanical design.
The manual design of turbines is an iterative redesign process involving the use of many sets of Computer Aided–Engineering (CAE) programs. The entire design process is modeled at four levels: analysis, automation, optimization, and concurrency. TAD is implemented with Engineous, a generic software shell for engineering design. Parts of TAD are already in use in day–to–day design practice for low–pressure turbines. In many cases of preliminary design, TAD can obtain better results quicker than the optimum obtained manually. Results also show that, for detailed aerodynamic analysis, the system can reduce the cycle time from days to hours.
Simulation of Diffuser Flow Using an Euler Solver With a Distributed Loss Model
Authors: Krückels J. , Mayer J. F. , Stetter H. 
Published: February 2015

The flow inside a diffuser which serves as outlet of the last turbine stage is strongly influenced by the tip leakage jet of the last blade row.
For the computation of diffuser flow a quasi 3D Euler solver with a simple model for the approximation of viscous effects was developed. A body force which is calculated as a function of velocity gradients normal to the streamwise direction is included in the Euler equations. Computational cost for calculations using this method remains low, permitting its use as a design tool for turbine diffusers.
Comparison of numerical results with experimental data for an annular axial radial diffuser at the outlet of a steam turbine model is presented. Flowfields for different tip clearances show a strong dependence of the pressure recovery on the tip leakage jet. Numerical results agree well with measurements.
Exploring How Shroud Constraint Can Affect Vibratory Response in Turbomachinery
Authors: Yang M.-T. , Griffin J. H. 
Published: February 2015

Unusual resonant responses were observed during spin pit tests of shrouded blades. The unusual behavior consisted of blades that exhibited strong response over a broad range of frequencies. The frequencies of peak response were considerably lower than predicted and were also lower than those observed in other tests of nominally identical wheels. In addition, the tracking plots of blade amplitudes versus frequency were truncated rather than displaying the usual sharp peaks seen in other tests. The unusual response is potentially dangerous since high vibratory response could be excited over a broad range of operating speeds.
The blades were designed to be free standing with gaps of approximately 10 milli-inches between neighboring shrouds. It is hypothesized that shroud contact at the blade tips could cause the unusual vibratory response. A simple model of a blade with shroud contact is developed in order to determine if shroud contact could cause blades to vibrate in the observed manner. The model is unusual in that it seeks to explore how contact could cause the blade to respond at lower (rather than higher) frequencies since contact typically increases the constraints on a structure and raises its natural frequencies.
Calibrating Ultrasonic Images for the NDE of Structural Materials
Authors: Gilmore Robert S. , Glaeser Andreas M. , Wade Janet C. 
Published: February 2015

Ultrasonic imaging is taking a larger and larger role in the NDE of turbine engine materials and in support of fracture mechanics calculations. It is also playing an increasing role in quality and process control. For most fracture toughness calculations, it is necessary to establish the accuracy with which a flaw’s size and shape are imaged, whether single or multiple flaws are involved, and the spacing of multiple flaws. Because of these requirements, resolution has become an issue as well as detection sensitivity. There are a number of resolution targets that can provide this type of calibration information for an ultrasonic imaging system. A fused quartz USAF 1951 target, similar to the patterns used in this work, was first used by Gilmore (1986), but Gilmore’s pattern was superficial and subsurface evaluations were limited to focusing on the pattern from the opposite side of the blank and monitoring the reflection from what is now the target backwall. Work by Peyton (1977) did produce buried targets in titanium samples, but there was no practical method to produce buried targets in high-temperature ceramics until the techniques developed by Rodel and Glaeser (1987) were used to produce the targets described in this paper.
Optically transparent resolution targets make it feasible to visually verify that the resolution target has been correctly fabricated. An image of the target with a candidate ultrasonic transducer then permits quantitative image resolution estimates to be made even when the interrogating acoustic beam contains significant refractive aberration. This is important because useful subsurface images can be acquired with the use of acoustic beams that are aberrated to the point that diffraction-limited beamwidth calculations are meaningless.
This work also demonstrates how the interdisciplinary skills of manufacturing companies can be combined with those of universities to produce results that any one of the individual members of the team could not have produced alone, without significant increases in labor, time, and cost.
NASA/GE Fan and Compressor Research Accomplishments
Authors: Smith Leroy H. 
Published: February 2015

Fan and compressor research projects carried out at GE Aircraft Engines under NASA sponsorship are described in this paper.
Four 1400-fps-tip-speed rotors designed with different airfoil shapes were found to have comparable stall lines but different efficiency trends. A stator placed behind one of these affected its performance somewhat. Adjustments of variable camber inlet guide vanes placed ahead of a 1500 fps stage were found to affect its pumping capability without much affecting its stall line.
For the Quiet Engine Program (QEP), two 1160-fps fans and one 1550-fps fan were tested. Development of the high-speed fan revealed the effects on performance of airfoil shape and part-span shroud blockage. The 950-fps variable-pitch fan for the Quiet Clean Short-Haul Experimental Engine (QCSEE) demonstrated reverse thrust capabilities and a novel method of avoiding large core inlet pressure losses during reverse thrust operation. The 1350-fps Energy Efficient Engine (E3) fan demonstrated excellent performance with a novel quarter-stage arrangement that eliminated the need for inter-spool bleed while giving good dirt removal potential.
The E3 compressor program employed Low Speed Research Compressor tests to identify the most appropriate blading type. High-speed rig tests and engine tests were then used to develop this 23:1-spool-pressure-ratio compressor.
Research on casing boundary layer control through bleeding and blowing led to the discovery that irregular casing geometries usually give stall line enhancements even without auxiliary air circuits. Some of the resulting casing treatment research is reported herein.
Instances in which NASA-sponsored research has affected GE Aircraft Engine products are pointed out.
Digital Control System Development for an Intercooled Recuperated Gas Turbine
Authors: Carlson R. J. , West P. M. , Azouz D. E. 
Published: February 2015

The on-going development of a full authority digital engine control (FADEC) system for the US Navy’s Intercooled Recuperated (ICR) gas turbine requires a high level of system coordination to achieve the primary benefits of reduced specific fuel consumption and improved specific output power relative to a simple cycle engine. This paper describes the system requirements analysis and the implementation of control algorithms leading to the preliminary ICR control system design.
The ICR control system is required to coordinate the actions of over 30 actuators using data taken from over 150 sensors. Primary control of the engine output power is provided by regulation of the fuel metering valve. Thermal management of the intercooler, recuperator, and variable area power turbine nozzle results in maximum cycle efficiency within safe operating limits.
The new electronic engine controller (EEC) is based on a new open architecture Futurebus+ backplane and is fully redundant in all operationally critical control functions. The EEC also features an operating panel and video display for local operation and maintenance of the control system. The graphical display and function keys provide access to control functions as well as assist maintenance activities with built-in test diagnostics to trouble shoot failed circuitry.
Advanced Hot Gas Cleaning System for Coal Gasification Processes
Authors: Newby R. A. , Bannister R. L. 
Published: February 2015

The United States electric industry is entering a period where growth and the aging of existing plants will mandate a decision on whether to repower, add capacity or do both. The power generation cycle of choice, today, is the combined cycle that utilizes the Brayton and Rankine cycles. The combustion turbine in a combined cycle can be used in a repowering mode or in a greenfield plant installation. Today’s fuel of choice for new combined cycle power generation is natural gas. However, due to a 300-year supply of coal within the United States, the fuel-of-the future will include coal.
Westinghouse has supported the development of coal-fueled gas turbine technology over the past thirty years. Working with the U.S. Department of Energy and other organizations, Westinghouse is actively pursuing the development and commercialization of several coal-fueled processes. To protect the combustion turbine and environment from emissions generated during coal conversion (gasification/combustion) a gas cleanup system must be used. This paper reports on the status of fuel gas cleaning technology and describes the Westinghouse approach to developing an advanced hot gas cleaning system that contains component systems that remove particulate, sulfur, and alkali vapors. The basic process uses ceramic barrier filters for multiple cleaning functions.
Working Group Activities of AGARD Propulsion and Energetics Panel
Authors: Ucer Ahmet S. 
Published: February 2015

One of the major activities of AGARD Panels is to form working groups which assemble experts who work on the particular subject for two or three years. As a result of the work an Advisory Report is published which compiles the state of the art knowledge on the chosen specific topic. This paper explains the philosophy and procedures adopted during the formation of working groups of the Propulsion and Energetics Panel.
Working groups concerning gas turbine technologies are presented. The selected working groups aim to improve the computational and experimental knowledge which would lead to the design of advanced aero gas turbine engines. Objective, scope, procedure, and important results of each Working Group will be explained. Working groups which were active during 1980’s and which are presently active are covered.
Laser and Micro-Plasma Welding of Single Crystal Blades: Advantages of Total Process Control
Authors: Pilcher C. , Liburdi J. , Berger C. , Iovene M. 
Published: February 2015

The single crystal superalloys, used in the manufacture of advanced gas turbine blades, are known to suffer from poor weldability and have a tendency to form cracks during and after welding. These cracks are largely related to the amount of heat input and metallurgical reactions that occur in the Heat Affected Zone (HAZ) adjacent to the weld. Experience has shown that cracks can be avoided by minimizing the HAZ through the use of proper heat management or process control.
Automation systems can offer the level of process control necessary to significantly reduce weld cracking. The systems have proven to be more repeatable, reliable, and efficient, compared to conventional techniques or earlier attempts at automation. In order to succeed, welding automation requires a complete integration of the process, consisting of tooling, robotic accuracy, vision measurement system, filler material, and welding parameter control. With the proper process control technology, it is possible to weld the tips of single crystal blades with difficult to weld oxidation resistant alloys as well as repair conventional compressor, high pressure and low pressure turbine blades.
This paper describes the welding of LT101 single crystal gas producer (GP) blade tips with highly alloyed filler metals for greater oxidation resistance. Results are presented for blades welded using a Laser beam with powder feed and compared to those welded using Micro-Plasma with the same filler alloys in wire form. The experience emphasizes the need for proper selection and integration of the welding processes, and confirms the importance of total process control to achieve the desired results in difficult and unique welding applications.
A Marine Installation of the Allison 570KF First Phase
Authors: Cheney Peter , Wall Richard 
Published: February 2015

With the obsolescence of the original cruise engine of the Canadian Navy DDH 280 Class Destroyers, it became necessary to find and fit a new cruise engine. The Allison 570KF engine was selected and installed during the half life refit and modernisation of the ship class. In addition to the engine replacement there were many changes to the support equipment which have had a large influence on the new installation.
This paper describes the first phase of the set to work and trials of the new installation and the difficulties encountered. Two ships are now at sea and undergoing extensive system trials as they carry out their Naval duties.
Deterministic and Stochastic Optimization of a Variable Axial Flow Compressor
Authors: Egorov I. N. 
Published: February 2015

A procedure is proposed to determine geometrical parameters and control laws of rows of a variable multistage axial flow compressor (VMAC) which are optimum by a criterion of ensuring turbomachine high efficiency within a wide range of operating modes under the row control. It is demonstrated that in shaping a layout of a variable compressor, it is expedient to determine its row geometry on the basis of control efficiency assessment. The paper illustrates a possibility to increase turbomachine efficiency (up to 8%) through optimum monitoring of its rows when studying a compressor as a separate unit and, also, through a decrease of specific fuel consumption (SFC) by 6% when studying a compressor as included in an engine.
The paper also presents the results of optimum profiling of 7 rows in a 4-stage variable compressor for a stochastic case, which enables to obtain optimum stable (robust) solution, permitting to increase a possibility to ensure design indices in its practical realization by 2 and more times.
Research and Development of Turbo Jet Combustor on HST Programme in Japan
Authors: Kuyama T. , Enzaki Y. , Kawano M. , Kobayashi M. 
Published: February 2015

The research and development of a turbo jet combustor for a Mach 3 class supersonic transport is underway, as well as the other components of the HST programme in JAPAN. This research and development aims finally at achieving a combustor exit temperature of 1973K while maintaining low NOx levels, high durability, and good exit temperature distribution.
This paper describes the interim status of the combustor research and development, in particular, the liner cooling system and exit temperature distribution control technique.
Environmental Aspects of a 10 MW Heavy Duty Gas Turbine Burning Coke Oven Gas With a Hydrogen Content of 60%
Authors: Becker T. , Perkavec M. 
Published: February 2015

In a coking plant in which coal tar is processed coke oven gas occurs as a waste product. Coke oven gas can be used as an alternative fuel for a gas turbine, instead of natural gas, if it meets the local environmental regulations.
As a result of higher flame temperature of coke oven gas caused by the hydrogen content, the NOx emission of a gas turbine burning coke oven gas is higher than in case of natural gas. In Germany a 10 MW gas fired gas turbine has to meet a NOx emission limit of 150 mg/Nm3 @ 15% O2 dry. To reach this goal in case of MS 3002, which is installed in the coking plant as reported in previous ASME paper, steam injection is necessary.
NOx- and CO-emissions of a gas turbine are difficult to be predicted by calculation, therefore measurements had to be done to see how good the predictions were, that were made in face of the local regulations.
This paper deals with the NOx- and CO-emissions of a coke oven gas fired gas turbine with and without steam injection in difference to natural gas fired gas turbine. It shows also significantly lower CO2-emissions, because coke oven gas contains less hydrocarbon which is a great benefit for the greenhouse problem. It illustrates the effect of power augmentation and discusses the different thermal efficiency with steam injection.
This paper gives a short glance to the effects which influence the emissions, so that the specific problems caused by burning coke oven gas can be understood.
Development of a Nonmetallic Abradable Material System for Gas Turbine Applications
Authors: Rose Daniel P. , Price George D. , Bosna Alexander 
Published: February 2015

The performance of gas turbine engines is highly dependent upon the clearance between compressor rotating blades or stator vanes, and adjacent shrouds. Auxiliary power units (APU) incorporate abradable coatings on compressor shrouds to allow for very small clearances and rub tolerance. The operating environment of the APU may result in a combination of abrasion between airfoil tips and shrouds, as well as galvanic corrosion of the abradable material. Experience has shown that established thermal spray abradable material systems that offer desirable abradability properties in laboratory testing may perform poorly when subjected to a combination of galvanic corrosion and abradable environment.
This paper discusses development and evaluation of an abradable material that is composed of nonmetallic constituents. This material is not susceptible to galvanic corrosion, and maintains its abradable properties when operating in a combined corrosive and abradable environment. The material development, microstructure, and physical properties are discussed. In addition, the performance of the material in abradability testing, and warm salt fog testing is presented.