bluuebunny/crossref_metadata_2025_split huggingface dataset:
Base-Metal Thermocouple Technology for Improved Temperature Measurement in Gas Turbine Engines
Authors: Furniss C. Paul 
Published: February 2015

During the next decade there will be growing pressures placed upon the manufacturers of gas turbines to produce more operationally efficient engines.
There are two main end-use groupings for gas turbines. The parameters for efficiency may prove to be quite different for these end-use groups, requiring a separate emphasis for engineering design.
With respect to aircraft propulsion gas turbines, the efficiencies may tend towards greater fuel economy and unit power outputs. In contrast to this the ground based gas turbine units may require increased unit power output but be restricted by the tightening emission requirements being dictated by international pollution laws.
One of the key areas of focus for engineering design, in order to satisfy such performance demands, is that of improved operational control of the turbine.
The process variables requiring accurate, reliable and repeatable monitoring and control include rotational speed, linear speed, pressure, mass flow rate and temperature. Whilst all of these phenomena require correct control, it may be argued that temperature is of extreme importance for both an operational efficiency and safety viewpoint.
This paper will attempt to explore the problems associated with conventional methods of gas turbine temperature measurement and discuss possible solutions using novel new technologies that will allow the earlier realisation of these efficiency goals.
Performance Criteria for Gas Turbine Cogeneration Plant
Authors: Sarabchi K. , Khoshravan E. 
Published: February 2015

With current gas turbine practice up to two-thirds of the energy available in the fuel is lost in the form of unused heat, By making practical use of this waste heat in a recovery boiler to produce steam for district heating or process applications it is possible to reduce the energy wastage to as little as 10 percent.
In this paper different performance criteria for assessment of a gas turbine cogeneration plant (GTCP) have been defined and compared with each other, Also, the practical range of performance criteria have been determined.
Numerical Investigations on the Effects of Swirling Combustor Exit Flow on HP-Turbine Inlet Flow for the Industrial Gas Turbine THM 1304
Authors: Bauermeister K. J. , Dohmen H.-J. , Simon H. 
Published: February 2015

To reduce gas turbine exhaust emissions the combustion system of the MAN GHH industrial gas turbine THM 1304 (ISO power 9250 kW) has been modified. The two outboard combustors in a V–configuration enabled to enlarge the chambers and thus to increase the retention time. Compared to the initial design the nature of combustor exit flow is considerably changed to an additional swirling flow.
To estimate the effects of these flow conditions on gas turbine performance the flow towards the high pressure turbine should be investigated. For that purpose a numerical flow simulation in the casing between the combustion chambers and the high pressure turbine nozzles has been accomplished. A Navier–Stokes–Solver (Finite Element Method) has been applied to the computation of the threedimensional turbulent flow.
The essential results, especially the flow conditions in front of the HP–turbine nozzles are presented with respect to the idealized combustor exit flow conditions. Besides the swirl strength, the direction of rotation and the swirl relation are varied. It is shown, that the flow at HP–turbine inlet is essentially characterized by the mainly centripetally directed combustor exit flow. Dependent on the above mentioned swirl flow parameters the characteristic flow distribution at HP–turbine inlet changes more or less. In the most favourable case the mass flow distribution at HP–turbine inlet varies circumferentially approx. ±14% and in the worst case approx. ±26%. Associated deviations from the ideal axial flow direction of approx. ±30° respectively ±40° are calculated.
A Novel Method for Refurbishing Used Hot Section Gas Turbine Blades
Authors: Kempster Adrian , Czech Norbert 
Published: February 2015

During the normal operation of a land based gas turbine attack will occur of the gas washed surfaces of the rotating and stationary blades in the turbine hot section. This attack and its intensity can be variable depending on the blades position in the turbine hot section. This attack will progressively degrade these gas washed surfaces even if these surfaces have been previously coated with a protective layer. During the service period of the turbine, it will be necessary to refurbish the blades from the hotter section of the turbine. One of the refurbishment steps will be to provide the blades with a suitable replacement coating to afford protection until the next service period.
Conventional refurbishment techniques used to clean the blade surface rely on abrasive cleaning and/or chemical pickling. These processes may be capable of removing superficial oxidation and any residual coating but are not able to consistently remove the substrate material that has suffered from corrosive attack. It is important that this attacked substrate layer is removed completely otherwise any residual corrosion products, particularly the presence of deeply penetrated sulphides in grain boundaries, could significantly reduce the life of any subsequent coating.
The technique described in this Paper essentially activates the surface layer of the substrate that is corroded, thus rendering it more easily removed by chemical and physical means. It is possible by this method to remove up to 400 microns of the substrate material and provided that all the corrosion products are contained within this zone, it is demonstrated how this produces a clean unattacked surface that is necessary for any subsequent welding, brazing or recoating operation.
Development of a Transonic Front Stage of an Axial Flow Compressor for Industrial Gas Turbines
Authors: Katoh Y. , Kashiwabara Y. , Ishii H. , Tsuda Y. , Yanagida M. 
Published: February 2015

This paper describes the aerodynamic blade design of a highly-loaded three-stage compressor, which is a model compressor for the front stage of an industrial gas turbine.
Test results are presented that confirm design performance. Some surge and rotating stall measurement results are also discussed.
The first stator blade in this test compressor operates in the high subsonic range at the inlet. To reduce the pressure loss due to blade surface shock waves, a shock-free airfoil is designed to replace the first stator blade in an NACA-65 airfoil in a three-stage compressor. Comparison of the performance of both blades shows that the shock-free airfoil blade reduces pressure loss.
This paper also presents some experimental results for MCA (multi-circular arc) airfoils, which are used for first rotor blades.
An Investigation of Boundary Layer Development in a Multistage LP Turbine
Authors: Hodson H. P. , Huntsman I. , Steele A. B. 
Published: February 2015

This paper describes an investigation of the behaviour of suction surface boundary layers in a modern multistage Low Pressure turbine. An array of eighteen surface-mounted hot-film anemometers was mounted on a stator blade of the third stage of a 4-stage machine. Data were obtained at Reynolds numbers between 0.9 × 105 and 1.8 × 105.
At the majority of the test conditions, wakes from upstream rotors periodically initiated transition at about 40% surface length. In between these events, laminar separation occurred at about 75% surface length. Because the wake-affected part of the flow appeared to be only intermittently turbulent, laminar separation also occurred at about 75% surface length while this flow was instantaneously laminar. At all but the lowest Reynolds numbers, the time-mean boundary layer appeared to have re-attached by the trailing edge even though it was not fully turbulent. It is inferred that the effect of the wakes on the performance of the bladerow is limited and that steady flow design methods should provide an adequate assessment of LP turbine performance during design.
Detailed Performance Comparison of a Dump and Short Faired Combustor Diffuser System
Authors: Carrotte J. F. , Denman P. A. , Wray A. P. , Fry P. 
Published: February 2015

A rectangular model simulating 4 sectors of a combustion chamber was used to compare the performance of a standard dump diffuser, of overall length 180mm, with that of a faired design 25.5mm shorter. The performance of each system was assessed in terms of total pressure loss and static pressure recovery between pre-diffuser inlet and the annuli surrounding the flame tube. Since the program objective was to test design concepts only, no allowance was made for the presence of burner feed arms or flame tube support pins. In addition, tests were performed with relatively low levels of inlet turbulence and no wake mixing effects from upstream compressor blades.
Relative to the dump design, the mass weighted total pressure loss to the outer and inner annuli was reduced by 30% and 40% respectively for the faired diffuser. Measurements around the flame tube head were used to identify regions of high loss within each system and account for the differences in performance. Within a dump diffuser the flow separates at pre-diffuser exit resulting in a free surface diffusion around the flame tube head and a recirculating flow in the dump cavity. This source of loss is eliminated in the faired system where the flow remains attached to the inner casing. Furthermore, the faired system exhibited similar velocity magnitudes and gradients around the combustor head despite its shorter length.
The Importance of the Nitrous Oxide Pathway to NOx in Lean-Premixed Combustion
Authors: Nicol David G. , Steele Robert C. , Marinov Nick M. , Malte Philip C. 
Published: February 2015

This study addresses the importance of the different chemical pathways responsible for NOx formation in lean-premixed combustion, and especially the role of the nitrous oxide pathway relative to the traditional Zeldovich pathway. NOx formation is modeled and computed over a range of operating conditions for the lean-premixed primary zone of gas turbine engine combustors.
The primary zone, of uniform fuel-air ratio, is modeled as a micro-mixed well-stirred reactor, representing the flame zone, followed by a series of plug flow reactors, representing the post-flame zone. The fuel is methane. The fuel-air equivalence ratio is varied from 0.5 to 0.7. The chemical reactor model permits study of the three pathways by which NOx forms, which are the Zeldovich, nitrous oxide, and prompt pathways. Modeling is also performed for the well-stirred reactor alone. Three recently published, complete chemical kinetic mechanisms for the C1-C2 hydrocarbon oxidation and the NOx formation are applied and compared.
Verification of the model is based on the comparison of its NOx output to experimental results published for atmospheric pressure jet-stirred reactors and for a ten atmosphere porous-plate burner. Good agreement between the modeled results and the measurements is obtained for most of the jet-stirred reactor operating range. For the porous-plate burner, the model shows agreement to the NOx measurements within a factor of two, with close agreement occurring at the leanest and coolest cases examined.
For lean-premixed combustion at gas turbine engine conditions, the nitrous oxide pathway is found to be important, though the Zeldovich pathway cannot be neglected. The prompt pathway, however, contributes small-to-negligible NOx. Whenever the NOx emission is in the 15 to 30ppmv (15% O2, dry) range, the nitrous oxide pathway is predicted to contribute 40 to 45% of the NOx for high pressure engines (30atm), and 20 to 35% of the NOx for intermediate pressure engines (10atm). For conditions producing NOx of less than 10ppmv (15% O2, dry), the nitrous oxide contribution increases steeply and approaches 100%.
For lean-premixed combustion in the atmospheric pressure jet-stirred reactors, different behavior is found. All three pathways contribute; none can be dismissed.
No universal behavior is found for the pressure dependence of the NOx. It does appear, however, that lean-premixed combustors operated in the vicinity of 10atm have a relatively weak pressure dependence, whereas combustors operated in the vicinity of 30atm have an approximately square root pressure dependence of the NOx.
An Asymptotic Analysis of Mixing Loss
Authors: Fritsch Gerd , Giles Michael B. 
Published: February 2015

The objective of this paper is to establish, in a rigorous mathematical manner, a link between the dissipation of unsteadiness in a 2D compressible flow and the resulting mixing loss. A novel asymptotic approach and a control-volume argument are central to the analysis. It represents the first work clearly identifying the separate contributions to the mixing loss from simultaneous linear disturbances, i.e. from unsteady entropy, vorticity, and pressure waves. The results of the analysis have important implications for numerical simulations of turbomachinery flows; the mixing loss at the stator/rotor interface in steady simulations and numerical smoothing are discussed in depth.
For a transonic turbine, the entropy rise through the stage is compared for a steady and an unsteady viscous simulation. The large interface mixing loss in the steady simulation is pointed out and its physical significance is discussed. The asymptotic approach is then applied to the first detailed analysis of interface mixing loss. Contributions from different wave types and wavelengths are quantified and discussed.
A Single Valve Gas Fuel Flow Control for Gas Turbines
Authors: Statler William O. 
Published: February 2015

A method of mass flow control of fuel gas to a gas turbine has been developed and applied in control retrofits to existing gas turbines. Unlike other gas flow control systems in use on gas turbines this system actually measures the mass flow going into the turbine combustion system and uses this value as the feedback in a control loop to modulate a single throttling control valve.
The system utilizes a common venturi flow element to develop a differential pressure which, along with inlet pressure and temperature, is used to compute the mass flow. Locating this flow element downstream of the control valve where the pressure is low at low flows reduces the usual problem of the wide range of delta-pressure (proportional to the square of the mass flow) to a workable level. This extends the range of this common type of flow measurement system enough that it becomes practical to apply it to the gas fuel flow control loop of a gas turbine.
Fast-Track Controls Retrofit for a Gas and Steam Turbine Propylene Compressor Drive
Authors: Morton James T. , Drobniak Joseph M. 
Published: February 2015

This paper chronicles a control system retrofit for a 38,000 horsepower refrigeration compressor drive at Novacor’s Ethylene #1 Plant, Red Deer, Alberta, Canada (Fig. 1). The changes were designed to meet a 3-year continuous operation requirement. When the plant was constructed in the late 1970’s, annual turnarounds were considered normal operating procedure.
The project replaced original electronic controls on a 23,500 horsepower G. E. Frame 5, Model R gas turbine and a 18,300 horsepower Elliott 2 NV starter/helper steam turbine. Both turbines are connected at opposite ends of a single compressor drive shaft (Fig. 2). Because of the cost associated with any control system malfunction, a programmable triple modular redundant controller was selected as the replacement.
Among the modifications performed to enhance system reliability were wiring dual exhaust thermocouples directly into the system and triplicating critical field devices. Another important aspect of this upgrade was replacing deteriorating underground field instrumentation wiring with cabling in overhead cable trays. The original wiring was over stressed by “frost heaving,” causing several unplanned shutdowns. In April of 1991, the project team initiated a schedule to meet an early August delivery. System specification, checkout, and start-up, as well as its first year of performance are discussed.
Exergy Analysis of Biomass-Fired Cogeneration Plant in a Pulp and Paper Mill
Authors: Näsholm Ann-Sofi E. , Svedberg Gunnar , Westermark Mats O. J. 
Published: February 2015

Second Law analysis or exergy analysis is a useful instrument to find ways to improve the efficiency of energy utilization. The method presents the magnitude and locations of true energy losses in an energy system.
The pulp and paper industries have a big potential for increasing the energy efficiencies. An integration of a gas turbine with an existing steam turbine plant is one possible way to increase the energy efficiency and the power production. The cogeneration plant analysed in this paper is a hybrid combined plant in which two types of fuels are used.
The exhaust gas from a combined cycle gas turbine via a waste heat recovery steam generator (HRSG) is used as preheated combustion air in a supplementary fired steam boiler. Saturated steam from the HRSG is assumed to be superheated in a boiler in which sludge, bark and other types of biomass are being used as fuels. To reduce the waste of energy, a flue gas driven fuel dryer is connected to evaporate some of the moisture in these biomass fuels.
The study shows the effect of using a combined cycle instead of a simple steam cycle and the effect of using a fuel dryer.
Among the configurations investigated, a plant with both a gas turbine and a fuel dryer yields the highest exergy efficiency and total efficiency. However, the net power efficiency is higher for a plant without a fuel dryer than for one with a fuel dryer.
Effect of Pressure on Second-Generation Pressurized Fluidized Bed Combustion Plants
Authors: Robertson Archie , Bonk Donald 
Published: February 2015

In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB coal/char combustion, gas turbine inlet temperatures higher than 1149°C (2100°F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871°C (1600°F), permitting sulfur capture by lime-based sorbents and minimizing the release of coal contaminants to the gases.
This paper presents the performance and economics of this new type of plant and provides a brief overview of the pilot plant test programs being conducted to support its development.
Advancement of Turbine Aerodynamic Design Techniques
Authors: Griffin Lisa W. , Huber Frank W. 
Published: February 2015

The Consortium for Computational Fluid Dynamics (CFD) Application in Propulsion Technology has been created at NASA/MSFC. Its purpose is to advance the state-of-the-art of CFD technology, to validate CFD codes and models, and to demonstrate the benefits attainable through the application of CFD in component design. Three teams are currently active within the Consortium: (1) the Turbine Technology Team, (2) the Pump Stage Technology Team, and (3) the Combustion Devices Technology Team. The goals, dynamics, and activities of the Turbine Team are the subjects of this paper.
The Consortium is managed by NASA. The Turbine Team is co-coordinated by a NASA representative from the CFD area and an industry (Pratt & Whitney) representative from the area of turbine aerodynamic design. Membership of the Turbine Team includes experts in design, analysis, and testing from the government, industry, and academia. Each member brings a unique perspective, expertise, and experience to bear on the team’s goals of improving turbine efficiency and robustness while reducing the amount of developmental testing. To this end, an advanced turbine concept has been developed within the team using CFD as an integral part of the design process. This concept employs unconventionally high turning blades and is predicted to provide cost and performance benefits over traditional designs. This concept will be tested in the MSFC Turbine Airflow Facility to verify the design and to provide a unique set of data for CFD code validation. Currently, the team is developing and analyzing methods to reduce secondary and tip losses to further enhance turbine efficiency. The team has also targeted volute development as an area that could benefit from detailed CFD analysis.
Chemical Vapor Deposition (CVD) Coatings for Protection of Jet Engine Components
Authors: Podob Mark 
Published: February 2015

CVD coatings are thin films resulting from the chemical reaction between a gaseous phase and the heated surface of a substrate. Among the industries using CVD coating technology are electronics, tooling, fuel cogeneration, and aerospace. The electronics industry uses CVD to deposit semiconductor materials onto different substrates. For the tooling industry, titanium nitride (TiN), titanium carbide (TiC), or aluminum oxide (Al2O3) is deposited onto cutting or metal forming tools. These hardcoatings act as chemical and thermal barriers between the tool and workpiece.
In the aerospace industry, CVD is used to deposit aluminide or chromide coatings onto jet engine blades and other hot section components. The coatings improve the corrosion and oxidation resistance of the base metal. CVD is replacing older established methods for protecting these same components. While the use of CVD coatings in the aerospace industry is relatively new, it is gaining increasing acceptance. In addition to producing aluminides and chromides, CVD reactions can form coatings containing silicon, yttrium, hafnium and other rare earth elements. Since the coatings are the result of the chemical reaction between high purity gases and solids, coatings can be free of porosity and inclusions.
Expanded SUMED System a Pipeline for the Future
Authors: Haddara Sherif Hassan 
Published: February 2015

This paper describes the Design, Engineering, Planning and Implementation activities that led up to an advanced, state of the art, optimum and economical solution for expanding an existing system to handle an increase of crude oil throughput from 80 to 117 mta metric tons per year (2.53 t/s to 3.71 t/s).
The growing demand and reduced net imports of products will increase Western European crude oil requirements to 11 million b/d (barrel per day) equivalent to 20.24 m3/s by year 2000.
SUMED (gulf of SUez - MEDiterranean) the Arab Petroleum Pipelines Company has historically secured about 40% of the market for middle Eastern crude oil movements to Europe.
Given these market shares on incremental volume SUMED should achieve its maximum design throughput of 117 mta by year 2000.
The SUMED pipelines system which is owned and operated by an Arab company having EGYPT, SAUDI ARABIA, KUWAIT, EMIRATES AND QATAR as share holders has been in operation since 1977. An expansion project has started to increase the throughput capacity of the system from 80 to 117 mta. The project completion is expected by mid 1994 with a total expenditure of 120 million dollars.
This paper reviews the evaluation and selection of various electric motor and gas turbines for the main pumping station addition for this pipeline expansion.