bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research of a High Thrust-to-Weight Ratio Small Turbofan Engine
Authors: Akagi Masahiro , Shinomiya Masashi , Sakaki Junichi , Sugai Shunji 
Published: December 2014

The 3rd Research Center of the Technical Research and Development Institute (TRDI) of Japan Defense Agency (JDA) and Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) developed and tested the demonstrator of a high thrust-to-weight ratio small turbofan engine with an afterburner called “XF3-400”, the purpose of which is to establish engine technologies for the future supersonic aircraft for JDA.
The development program started in 1981 and the first engine test was carried out in 1992. All the engine tests planned completed in March 1995 successfully.
This paper reports the design, development and test results of the XF3-400 engine above.
Computation of Leading-Edge Film Cooling With Injection Through Rows of Compound-Angle Holes
Authors: Lin Y.-L. , Stephens M. A. , Shih T. I-P. 
Published: December 2014

Computations were performed to investigate the three-dimensional flow and heat transfer about a semi-cylindrical leading edge with a flat afterbody that is cooled by film-cooling jets, injected through three staggered rows of compound-angle holes with one row along the stagnation line and two rows along ±25°. Results are presented for the surface adiabatic effectiveness, temperature distribution, velocity vector field, turbulent kinetic energy, and surface pressure. These results show the interactions between the mainstream hot gas and the cooling jets, and how those interactions affect surface adiabatic effectiveness. The computed results were compared with experimental data generated under a blind test, and reasonably good agreements were obtained.
This computational study is based on the ensemble-averaged conservation equations of mass, momentum (compressible Navier-Stokes), and energy closed by a low Reynolds number k-ω turbulence model. Solutions were generated by a cell-centered finite-volume method that uses second-order accurate flux-difference splitting of Roe on a multiblock structured grid system. In the computations, the flow is resolved not just in the region about the leading edge, but also inside the film-cooling holes and in the plenum where the cooling flow emerges.
Dynamic Instabilities in Natural-Circulation Evaporators of Vertical HRSGs
Authors: Payrhuber Klaus , Halozan Hermann 
Published: December 2014

Dynamic instabilities become increasingly one of the design criteria for natural-circulation evaporators in Heat Recovery Steam Generators (HRSGs) of combined cycle power plants, especially in systems with a vertical gas duct. To calculate such instabilities, the computer program DEDYN is being developed. The calculation method has been presented at the ASME Cogen-Turbo Power 1995 in Vienna (Payrhuber, 1995).
This publication deals with modeling of a natural-circulation evaporator. The evaporator investigated in this paper consists of 340 parallel finned tubes in 4 layers of 16 meters (total tube length of one tube is 64 meters) and a total heat transfer surface of 16400 square meters. This heat exchanger bundle of a HRSG with a vertical duct is divided in 8 sub-ducts, which permits a calculation with local heating medium (= flue gas) temperatures. The inlet and outlet headers of this bundle are connected to a drum.
Several variations have been investigated like changing the operation pressure, different heights of the drum, subcooling when entering the downcomer, as well as parallel flow or counter flow through the evaporator tube bundle. The paper shows the boundary conditions for preventing or at least damping mass flow oscillations in the evaporator.
A Review of Some Current Problems in Gas Turbine Secondary Systems
Authors: Turner A. B. , Long C. A. , Childs P. R. N. , Hills N. J. , Millward J. A. 
Published: December 2014

This paper reviews the current position of five major problem areas in gas turbine secondary air system design. Although the problems are of primary interest to the designer of the coolant flow paths, since they directly affect the temperature, the stresses and thus the life of the major rotating components, three of the problems interact with the main gas path and are thus also the concern of the mainstream aerodynamicist.
The five problems reviewed are: prediction of the flow distribution and heat transfer in the high pressure compressor drive cone cavity from the turbine to the rim of the HP compressor running underneath the combustion chamber, the flow penetration and heat transfer in the multiple rotating cavities formed by the multiple discs of the high pressure compressor with a rotating shaft running through the bores; the control of ingestion of hot turbine mainstream gas into the rotor-stator wheelspaces through the rim-seals; the problem of compressor and turbine stator-well heating, particularly compressor stator-wells in which excessive temperatures have been occasionally measured and finally, the pre-swirl coolant system which has to take the blade cooling air across from the stationary casing to the rotating turbine disc in the most advantageous manner.
Quantitative Visualization of Full-Coverage Discrete-Hole Film Cooling
Authors: Fric Thomas F. , Campbell Robert P. , Rettig Mark G. 
Published: December 2014

Water tunnel experiments were carried out to study full-coverage discrete-hole film cooling for geometries applicable to gas turbine combustor liners. The cooling holes were spaced at a pitch to diameter ratio of 6.5 and had an injection angle of 20° to the cooled surface. The mainstream flow direction was in line with the cooling holes. Blowing ratios from 0.5 to 5.7 were studied, which is a range typical of combustor liners.
A unique multiple plane PLIF (planar laser-induced fluorescence) technique was used to measure time-averaged film cooling concentration at various heights above the surface to be cooled. Three-dimensional data sets were generated to quantitatively visualize cooling-jet film coverage, structure, and interaction. Film coverage as close as 0.25 mm (0.010 in.) from the surface was measured, thereby yielding data that approach adiabatic film effectiveness. Two sets of film cooling experiments were conducted. One set used a model with a relatively small array of 2.54 mm (0.100 in.) holes, meant to be a large-scale model of hole sizes encountered in combustor liners. The second set used a large array of 0.51 mm (0.020 in.) nominal diameter laser-drilled holes, manufactured in the same manner as combustor liner cooling holes.
The results show that near-wall film coverage is minimum for blowing ratios from 1.7 to 3.3. At blowing ratios less than 1.7 and greater than 3.3, the film coverage was improved. Jet structure and interaction was also observed. In particular, jet separation behavior and coalescence were visualized, and both were generally a function of blowing ratio.
The Design of an Instructional Cogeneration Laboratory
Authors: Banta Andrew 
Published: December 2014

California State University, Sacramento has designed and constructed a cogeneration laboratory for the instruction of students in modern electrical generation. This facility serves about 100 senior level students per year. The major components are a 75 kW gas turbine generator, a waste heat boiler and a small absorption chiller. Future plans include the addition of a 50 kW steam turbine.
The analytical design of this plant is described from concept to final layout with particular emphasis on cycle analysis, selection and sizing of components and instrumentation, and the layout of the equipment. A diagram showing the entire cycle on a scaled temperature entropy plot provides an interesting graphical interpretation of the plant’s operation. While the gas turbine has a relatively low pressure ratio of 3.3:1 and thus a low thermal efficiency, the addition of the other components improves the performance significantly.
An aspect of the analysis of particular interest is relating the cooling of the chiller to an equivalent work term thus enabling the determination of an overall thermal efficiency. If all of the steam were to be used for cooling the plant efficiency would improve slightly from 10% for the turbine alone; when made equivalent to other types of refrigeration the improvement is more than 6%. When all of the steam is used in the proposed steam turbine the efficiency will improve to about 17%. Using the chiller to cool inlet air to the gas turbine—thus increasing performance—is discussed at length. Student use of the laboratory is discussed briefly.
While the plant is quite small and intended for laboratory use, the design analysis is applicable to similar plants which might be used in remote locations, or as stand-by or peaking power supplies.
Detailed Off Design Flow Measurements in a Centrifugal Compressor Vaned Diffuser
Authors: Pinarbasi Ali , Johnson Mark W. 
Published: December 2014

Three component hot wire measurements in the vaneless space and vane region of a low speed centrifugal compressor vaned diffuser are presented. These comprise mean velocity and turbulence level distributions for a below and above design flow rate for three vane-to-vane locations at each of five radial measurement stations.
The flow entering the diffuser closely resembles the classic jet-wake flow characteristic of centrifugal impeller discharges. A strong upstream influence of the diffuser vanes is observed which results in significant variations in flow quantities between the vane-to-vane locations. The circumferential variations due to the passage and blade wakes rapidly mix out in the vaneless space, although some variations are still discernible in the vaned region. Comparison with results in a vaneless diffuser suggest that the presence of the vanes accelerates this mixing out process.
Oxidation Behavior of Ceramics for Gas Turbines in Combustion Gas Flow at 1500°C
Authors: Etori Y. , Hisamatsu T. , Yuri I. , Yasutomi Y. , Machida T. , Wada K. 
Published: December 2014

In order to evaluate the durability of silicon-carbides (SiC) and silicon-nitrides (Si3N4), we studied the oxidation behavior of SiC and Si3N4 in 1500°C combustion gas flow. We found that the exposure to the combustion gas flow resulted in the weight losses of those ceramics due to the partial disappearance of the oxidized surface layer.
We investigated the effects of sintering aids and high speed gas flow as possible factors for the disappearance of the oxide layer. Two kinds of SiC, without sintering aids and sintered with B4C, were used as test specimens. After the exposure to combustion gas flow conditions of 1500°C, 150m/s, 0.18MPa, the weight loss rate and thickness of the oxide layer were quite the same for each specimen of SiC. The existence of sintering aids did not have any effect on the disappearance of the oxide layer. To investigate the effect of gas flow, we set each specimen in a tube made of SiC to protect it from the gas flow. The tube had two holes each acting both as inlet and exhaust vents. Consequently, the oxide layer formed thickly. But at the spots on the specimen facing the holes, the oxide layer was thin. Hollows occurred on the specimen of SiC at these spots. It seems that the existence of gas flow is a very important factor in the disappearance of the oxide layer.
Alumina (Al2O3) and zirconia (ZrO2) as oxide ceramics were exposed to the combustion gas flow. The weight of these also decreased. There is a possibility that the weight loss of ceramics in combustion gas flow is caused by degradation of oxide layer on their surface from erosion and hot corrosion due to some oxide scales coming from the test equipment.
The Analysis and Resolution of a Fatigue Failure of a Low Pressure Turbine Blade Caused by the Excitation of a Bladed Disc Mode of Vibration
Authors: Staddon Malcolm C. , Box Paul R. , Barnett Barry , Horton Tony , Ballans Geoff H. 
Published: December 2014

A high cycle fatigue failure of a low pressure turbine blade was investigated. Strain gauge tests of a running engine indicated a high dynamic response of the blade at the nozzle passing frequency. This could be attributed to the excitation of a bladed disc mode of vibration. A Finite Element analysis of the low pressure turbine blades and discs, together with bench testing of the complete structure, confirmed the existence of a high frequency 2nd Nodal Diameter mode of vibration. The levels of dynamic strain determined through strain gauge tests were found to be sufficient enough to explain the failure at the given location.
Having understood the problem, the situation was resolved through the use of Finite Element analysis with a short term modification to the original blade aerofoil to prevent the mode from being excited.
An aero/mechanical re-design of both the low pressure turbine rotor and the stator was undertaken to resolve the problem by both returning the blade to avoid high frequency excitation, and also by reducing the forcing effect of the nozzle passing frequency. The new design has been validated through strain gauge tests and endurance tests. A further improvement in performance was also obtained.
Advances in Gas Turbine Blade Repair by Laser Welding
Authors: Gandini Ettore , Agnesone Franco , Taricco Federica , Arrighi Leonardo 
Published: December 2014

Industrial gas turbine components are subject, in the course of their operating life, to various kinds of damages, requiring repair processes during periodical overhauling operations. Blades, in particular, suffer from creep, corrosion, wear phenomena.
The majority of blade damage is currently repaired by means of manual TIG welding, with a filler metal which is often different from the blade alloy. This leads to an inferior metallurgical and mechanical condition of the repaired area as compared to the base metal. Besides, the nickel superalloys of the blades are often subject to cracking during welding operations.
A process of laser welding for the repair of the airfoil tip has been introduced and optimized, to improve the characteristics of the repaired component. Powder of the same alloy of the part is used as filler metal, and the process is carried out using a Nd:YAG laser, equipped with a 6–axis CNC motion control. The original blade geometry is rebuilt by multi–layer cladding, then the blade is submitted to machining operations, NDT testing and heat treatment.
The optimizing activity has been performed with the aid of microstructural characterization, chemical composition checking (by EDX microanalysis), hardness and stress rupture testing of the welded specimens.
Application of CFD to DLN Combustion
Authors: Hornsby C. , Norster E. R. 
Published: December 2014

This paper describes the methodology and application of Computational Fluid Dynamics (CFD) to Dry Low NOx (DLN) combustion systems throughout the range of small industrial gas turbines produced at European Gas Turbines (EGT) Lincoln UK.
The use of CFD in the development of such systems has been encouraged not only by the availability of a variety of general purpose CFD codes, but also by the inherent difficulties associated with direct measurement in such a harsh environment. Combusting flow analyses provide detailed predictions of local temperature and velocity fields together with exhaust emissions, enabling numerous conceptual studies to be undertaken without the usual associated mechanical difficulties.
In particular, the work EGT has concentrated on concerns the prediction of fuel / air mixing quality upstream of the flame front, in order to assess the effect of fuel injector design variables on NOx production. This methodology has accelerated injector development resulting in less than 10 ppmV NOx combustors.
Validation of the detailed features of the flow field is currently underway, though parametric comparisons have already proved consistently accurate in displaying the trends necessary for the development of an ultra low NOx combustion system. Correlations of rig emissions data with overall predictions have shown to be in good agreement.
Thermal Optimisation of Longitudinal Ribs in Variable Geometry Ducts
Authors: Naik S. , Probert S. D. 
Published: December 2014

Augmenting the heat transfer rates in the internal flow passages of several components of a gas turbine, such as the turbine blades, vanes and combustor walls is an important pre-requisite for maintaining their structural integrity. This is particularly paramount when higher turbine inlet temperatures and pressure ratios are utilised for enhancing the thermal efficiencies of the gas turbine plant.
In this study, the heat transfer enhancement, which can be achieved by longitudinal ribs in a variable geometry duct, has been examined. With the base of the ribs maintained at a constant temperature, it was observed that the optimal rib spacing, which corresponded to the maximum heat transfer from the ribs, was a strong function of the rib height to length ratio and the Reynolds number but relatively insensitive to the amount of clearance above the ribs. A design correlation is proposed which shows the distribution of this optimal rib spacing for a wide range of rib geometrical and operational conditions.
Comparisons of the longitudinal ribs with pin fin arrays indicated that at rib height to length ratios of ≥ 0.24, higher heat transfers can be achieved with the longitudinal ribs. The frictional characteristics of the longitudinal ribs is comparable to those of circular pin fins.
Measurements of the local heat transfer coefficient for the rib surfaces indicate that it is highly non-uniform along the rib height and length and also significantly influenced by the amount of clearance above the ribs. For all the cases examined, it was observed that developing flow conditions (thermally and hydrodynamically) were prevalent within the longitudinal rib channels.
Prospect of Advanced Generation Technologies in a Competitive Marketplace
Authors: Guha Manoj K. 
Published: December 2014

To meet the challenge of deregulation and customer demands for a free competitive market, the electric utility industry in the U.S. (and, for that matter, throughout the world) will experience tremendous changes over the next five years. These changes will be driven by two major forces: the deregulation of the industry and, therefore, no guaranteed return on investment but more importantly, the demands of customers for a free competitive market in the electric utility industry where they can achieve the lowest cost for the commodity. This will force utility companies to position themselves as low-cost producers. Although low cost does not necessarily mean success, it is obvious that cutting and/or reducing capital expenditures will play the most important role.
Unregulated markets encourage product diversity, as firms look for “niche” profit opportunities. A pervasive lesson from other industries that have recently been deregulated clearly shows that unless properly planned, these companies will not only do poorly but may be completely wiped out from the market Generation Planning (base load vs. peak load, long-term vs. short-term) will become more important since two-thirds of the capital investment is tied to generation facilities. While low-cost utilities will have greater flexibility in adapting to competition, they will be far from immune to industry changes.
Under a fully competitive marketplace, all generating plant assets/investments will come out of a rate base. Since all companies will be exposed to competition, high-cost generating assets would no longer be subsidized by ratepayers. This will force the utility companies to invest in low capital cost generation only, at least during the next ten to fifteen years.
This paper will briefly discuss the status of various advanced generation technologies with respect to their costs, applicability and limitations, where these technologies are expected to be cost effective and finally how these technologies compare with the state-of-the-art combined cycle gas-turbine technology. It is predicted that as environmental regulations tighten on pollution, advanced generation technologies may benefit at the expense of current fossil fuel technologies. However, it is not certain whether economic growth in the U.S. can be sustained if new regulations on pollution force to add new plants with advanced generation technologies, compared to continuing with today’s generation mix. It will be examined how, when and where the advanced generation technologies would play an important role in penetrating the market on their own merits.
Local Heat Transfer Coefficients on Flat Continuous, Flat Interrupted and Corrugated External Cooling Fins
Authors: Robertson Andrew J. , Neely Andrew J. , Ireland Peter T. , Harper Les R. 
Published: December 2014

An experimental investigation into the performance of gas turbine engine component external cooling fins has been carried out using the transient liquid crystal technique in a low speed wind tunnel. Full fin surface local heat transfer coefficient distributions have been determined. Measurements with this level of resolution are not previously reported in the literature.
In addition to the flat continuous fins, interrupted and corrugated fin geometries have been tested. These geometries enhance heat transfer coefficients by disrupting the thermal and velocity boundary layers which grow down the length of the fin.
All geometries are tested at a range of flow speeds and comparisons are made with the relevant literature.
Grid Dependency Study for the NASA Rotor 37 Compressor Blade
Authors: Arnone Andrea , Carnevale Ennio , Marconcini Michele 
Published: December 2014

The NASA Rotor 37 has been computed by several authors in the last few years with relative success. The aim of this work is to present a systematic grid dependency study in order to quantify the amount of uncertainty that comes from the grid density. The computational domain is divided onto several regions (i.e. leading edge, trailing edge, shear layer …) and for each of them, the impact of the grid density is investigated.
By means of this analysis, substantial improvement has been obtained in the prediction of efficiency and exit angle. On the contrary, the improvement achieved in total pressure and total temperature ratio is less remarkable. It is believed that only after a systematic grid dependency study can the contribution of turbulence modeling, laminar-turbulent transition, and boundary conditions be analyzed with success.