bluuebunny/crossref_metadata_2025 huggingface dataset:
Standards for Advanced Ceramics and Pre-Standardization Research: A Review
Authors: Morrell Roger
Published: February 2015

To support the advanced ceramics infrastructure in terms of ability to acquire reliable property and performance data, and to define tests for specifications, the development of testing standards has had priority in Europe through CEN (Comité Européen de Normalisation) over the past six years. The maintenance of close links with other standardisation bodies, including ASTM, JIS, and now ISO, has been important, and has been achieved through the international ceramics community. This has minimized technical differences between standards produced in different parts of the world. A review of progress in the preparation of formal CEN standards for monolithic ceramics is presented, which comprises a programme with a target of about eighty standards to be available by 1998. Some of the outstanding problems and requirements are identified. The role of pre-standardization research programmes and interlaboratory comparison is emphasized, including national and international programmes within the European Union. In particular, collaborative work under the auspices of VAMAS has proved to be a valuable method of obtaining internationally agreed positions on some of the technical issues.
A Gas Turbine Propulsion Plant With the Capability to Provide Steam for Both Injection and Aircraft Catapults
Authors: Wen Xueyou , Wei Yingxin , Jin Jierong , Fu Zhen
Published: February 2015

Proposed in this paper is a novel propulsion system. On the basis of a gas turbine Brayton cycle a Rankine regenerative cycle was set up in parallel, which by utilizing the waste heat of the gas turbine exhaust gas is able to flexibly supply steam for gas turbine steam injection and for aircraft catapults. Thus brought forth is a gas turbine propulsion plant with a dual-purpose steam supply, which can well be suited for use on board an aircraft carrier. The propulsion plant under discussion has the inherent merits of a steam injected gas turbine cycle, but the additional new feature of steam supply for aircraft catapults significantly enhances the advantages of the propulsion plant as a whole. With a medium-sized aircraft carrier being selected as an example a comprehensive comparison has been conducted of four types of propulsion power plants, including a gas turbine propulsion plant with the capability to supply steam for both gas turbine steam injection and aircraft catapults.
WR-21 Design and Maintenance
Authors: Weller Carl L. , Broadbelt Alastair , Law Bernard
Published: February 2015

WR-21 is the designation for the Intercooled, Recuperated (ICR) Gas Turbine Engine System currently under development for the U.S. Navy (USN). The Royal Navy and the French Navy are also program participants. The purpose of the program is to design, develop, and qualify a fuel efficient engine for future surface ships. Since inception, a key focus of the program has been to design for maintainability. As a result, the WR-21 design incorporates a number of innovative support and maintenance features. This paper provides a description of the WR-21 engine system and its maintenance features.
Computation of the Unsteady Transonic Flow in Harmonically Oscillating Turbine Cascades Taking Into Account Viscous Effects
Authors: Grüber B. , Carstens V.
Published: February 2015

This paper presents the numerical results of a code for computing the unsteady transonic viscous flow in a two-dimensional cascade of harmonically oscillating blades. The flow field is calculated by a Navier-Stokes code, the basic features of which are the use of an upwind flux vector splitting scheme for the convective terms (Advection Upstream Splitting Method), an implicit time integration and the implementation of a mixing length turbulence model.

For the present investigations two experimentally investigated test cases have been selected in which the blades had performed tuned harmonic bending vibrations. The results obtained by the Navier-Stokes code are compared with experimental data, as well as with the results of an Euler method.

The first test case, which is a steam turbine cascade with entirely subsonic flow at nominal operating conditions, is the fourth standard configuration of the “Workshop on Aeroelasticity in Turbomachines”. Here the application of an Euler method already leads to acceptable results for unsteady pressure and damping coefficients and hence this cascade is very appropriate for a first validation of any Navier-Stokes code. The second test case is a highly-loaded gas turbine cascade operating in transonic flow at design and off-design conditions. This case is characterized by a normal shock appearing on the rear part of the blades’s suction surface, and is very sensitive to small changes in flow conditions. When comparing experimental and Euler results, differences are observed in the steady and unsteady pressure coefficients. The computation of this test case with the Navier-Stokes method improves to some extent the agreement between the experiment and numerical simulation.
A Semiclosed Cycle Gas Turbine With Carbon Dioxide-Argon as Working Fluid
Authors: Ulizar Inaki , Pilidis Pericles
Published: February 2015

This paper describes the performance analysis of a semi closed cycle gas turbine. The working fluid is carbon dioxide and the fuel is low heating value gas synthesised from coal. The objective of the machine is to produce clean electricity with the smallest efficiency penalty.

Firstly the thermodynamic properties of the gases in the cycle were obtained as a function of temperature and pressure. Then two performance simulation codes were developed. These have the ability of simulating different configurations of open, closed and semi-closed cycles. The first code was used for cycle optimisation and the second for off-design studies.

The design and off-design performance of the machine are predicted. The production of clean electricity will be at the expense of a lower efficiency compared with current equipment. Finally, some critical issues for the development of such a gas turbine are identified.
Progress in Fabrication of Silicon Nitride Structural Components for Turbomachinery Applications
Authors: Pollinger John P.
Published: February 2015

The development and refinement of high performance silicon nitride structural ceramic materials over the last five years is leading to evaluation and implementation of components in aircraft, space, industrial, and automotive turbomachinery applications. Current material properties, status of component fabrication technologies, and status of applications being evaluated and commercialized at AlliedSignal Ceramic Components is discussed. Currently achievable properties of in-situ reinforced monolithic silicon nitride materials are presented. The development and status of component forming processes is also discussed, including their potential as manufacturing processes. The processes discussed include slipcasting, green machining, gelcasting, and injection molding. Finally, status of silicon nitride component fabrication and evaluation in a number of applications is discussed, including nozzle, blade, and wheel components for the U.S. Department of Energy (DOE) automotive turbine technology programs, the DOE Advanced Turbine Systems industrial turbine technology program, and a NASA-funded program to develop advanced rocket engine turbopumps.
Development of a High Specific Speed Centrifugal Compressor
Authors: Rodgers C.
Published: February 2015

This paper describes the development of a subscale single stage centrifugal compressor with a dimensionless specific speed (Ns) of 1.8, originally designed for full size appllcatioa as a high volume flow, low pressure ratio, gas booster compressor. The specific stage is noteworthy in that it provides a benchmark representing the performance potential of very high specific speed compressors of which limited information is found in open literature. Stage & component test performance characteristics are presented together with traverse results at the impeller exit. Traverse test results were compared with recent CFD computational predictions, for a exploratory analytical callbration of a very high specific speed impeller geometry.

The tested subscale (0.583) compressor essentially satisfied design performance expectations with an overall stage efficiency of 74% incinding, excessive exit casing losses. It was estimated that stage efficiency could be increased to 81% with exit casing losses halved.
REVAP® Cycle: A New Evaporative Cycle Without Saturation Tower
Authors: De Ruyck J. , Bram S. , Allard G.
Published: February 2015

A new evaporative cycle layout is disclosed which is shown to have a performance similar to the HAT cycle, but where the saturation tower has been eliminated. This new cycle is a result from a combined exergetic and composite curve analysis discussed in a previous paper, assuming one intercooler and no reheat (De Ruyck et al, 1995). The new cycle uses two-phase flow heat exchange in the misty regime, which is a well known process. Existing aeroderivative gas turbine equipment can be adapted for application of this cycle, which therefore needs a minimum of development.
Radial Turbine Development for the 100kW Automotive Ceramic Gas Turbine
Authors: Nakazawa Norio , Ogita Hiroshi , Takahashi Masayuki , Yoshizawa Takaaki , Mori Yasumasa
Published: February 2015

The development of turbine components for the automotive 100kW ceramic gas turbine has entered the final stage of the seven-year project and is making satisfactory progress toward the goals. We have attained the interim targets of the aerodynamic performances and have been carrying out tests to further improve efficiency. As for ceramic parts, we have changed the material of the turbine rotor to a new one that is excellent in long-sustained and high-temperature strength properties, and have confirmed substantial strength at high temperature through hot-spin tests. After evaluating blade-vibration stress through analyses and experiments, we completed an endurance evaluation at 1,200°C (1,473K) TIT (Turbine Inlet Gus Temperature) and a rated speed of 100,000rpm. We are now carrying out endurance tests at 1350°C (1,623K) TIT. For ceramic stationary parts, we already finished the evaluations at 1,200°C TIT and are also conducting an endurance test at 1,350°C TIT. Using these parts in a full-assembly test, together with other elements, we confirmed that they cause no functional problem in tests performed at 1,200°C TIT level up to the rated speed (100,000rpm), and are evaluating their performances.
A Viscoplastic Constitutive Theory for Monolithic Ceramics: I
Authors: Janosik Lesley A. , Duffy Stephen F.
Published: February 2015

This paper, which is the first of two in a series, provides an overview of a viscoplastic constitutive model that accounts for time-dependent material deformation (e.g., creep, stress relaxation, etc.) in monolithic ceramics. Using continuum principles of engineering mechanics the complete theory is derived from a scalar dissipative potential function first proposed by Robinson (1978), and later utilized by Duffy (1988). Derivations based on a flow potential function provide an assurance that the inelastic boundary value problem is well posed, and solutions obtained are unique. The specific formulation used here for the threshold function (a component of the flow potential function) was originally proposed by Willam and Warnke (1975) in order to formulate constitutive equations for time-independent classical plasticity behavior observed in cement and unreinforced concrete. Here constitutive equations formulated for the flow law (strain rate) and evolutionary law employ stress invariants to define the functional dependence on the Cauchy stress and a tensorial state variable. This particular formulation of the viscoplastic model exhibits a sensitivity to hydrostatic stress, and allows different behavior in tension and compression.
Characterization of Laws of Friction in the Context of Engine Blade Dynamics
Authors: Srinivasan A. V. , McFarland D. Michael
Published: February 2015

Experience has shown that energy dissipation due to rubbing at interfaces of engine blade shrouds provides damping of bladed disk assemblies. An accurate estimate of such damping has been a subject of study for more than a decade. The most difficult parameter that influences its accurate calculation pertains to an appropriate definition of the laws of friction that relate the rubbing motion with the forces induced.

This paper develops an analysis which leads to a mathematical relationship between the forces of friction damping at a vibrating interface and the corresponding relative motion. The analysis permits calculation of forces at the interface if the displacements are known or vice versa. The equations are cast in terms of relative motion between mating shrouds so that degenerate cases of fully locked and freely slipping can be calculated. Examples are given showing simulation results obtained using discrete structural models. Extension of the analysis to the case of a full assembly is discussed.
Creep Performance of Candidate SiC and Si3N4 Materials for Land-Based, Gas Turbine Engine Components
Authors: Wereszczak Andrew A. , Kirkland Timothy P.
Published: February 2015

The tensile creep-rupture performance of a commercially available gas pressure sintered silicon nitride (Si3N4) and a sintered silicon carbide (SiC) is examined at 1038, 1150, and 1350°C. These two ceramic materials are candidates for nozzles and combustor tiles that are to be retrofitted in land-based gas turbine engines, and interest exists to investigate their high temperature mechanical performance over service-times up to, and in excess of, 10000 hours (≈ 14 months). To achieve lifetimes approaching 10000 hours for the candidate Si3N4 ceramic, it was found (or it was estimated based on ongoing test data) that a static tensile stress of 300 MPa at 1038 and 1150°C, and a stress of 125 MPa at 1350°C cannot be exceeded. For the SiC ceramic, it was estimated from ongoing test data that a static tensile stress of 300 MPa at 1038°C, 250 MPa at 1150°C, and 180 MPa at 1350°C cannot be exceeded. The creep-stress exponents for this Si3N4 were determined to be 33, 17, and 8 for 1038, 1150, and 1350°C, respectively. The fatigue-stress exponents for the Si3N4 were found to be equivalent to the creep exponents, suggesting that the fatigue mechanism that ultimately causes fracture is controlled and related to the creep mechanisms. Little success was experienced at generating failures in the SiC after several decades of time through exposure to appropriate tensile stress; it was typically observed that if failure did not occur on loading, then the SiC specimens most often did not creep-rupture. However, creep-stress exponents for the SiC were determined to be 57, 27, and 11 for 1038, 1150, and 1350°C, respectively. For SiC, the fatigue-stress exponents did not correlate as well with creep-stress exponents. Failures that occurred in the SiC were a result of slow crack growth that initiated from the specimen’s surface.
Characterization and Laboratory Simulation of Turbine Airfoil Surface Roughness and Associated Heat Transfer
Authors: Bogard David G. , Schmidt Donald L. , Tabbita Martin
Published: February 2015

The physical characteristics of surface roughness observed on 1st stage high pressure turbine vanes which had been in service for a long period were investigated in this study. Profilometry measurements were utilized to provide details of the surface roughness formed by deposits of foreign materials on different parts of the turbine vane. Typical measures of surface roughness such as centerline average roughness values were shown to be inadequate for characterizing roughness effects. Using a roughness shape parameter originally derived from regular roughness arrays, the turbine airfoil roughness was characterized in terms of equivalent sandgrain roughness in order to develop an appropriate simulation of the surface for laboratory experiments. Two rough surface test plates were designed and fabricated and these test plates were evaluated experimentally to quantify the heat transfer rate for flow conditions similar to that which occur on the turbine airfoil. Although the roughness levels on the two test plates were different by a factor of two, both surfaces caused similar 50% increases in heat transfer rates relative to a smooth surface. The effects of high free-stream turbulence, with turbulence levels from 10% to 17%, were also investigated. Combined free-stream turbulence and surface roughness effects were found to be additive, resulting in as much as a 100% increase in heat transfer rate.
Rotation Effect on Jet Impingement Heat Transfer in Smooth Rectangular Channels With Four Heated Walls and Radially Outward Cross Flow
Authors: Parsons J. A. , Han J. C. , Lee C. P.
Published: February 2015

The effect of channel rotation on jet impingement cooling by arrays of circular jets in two channels was studied. Jet flow direction was in the direction of rotation in one channel and opposite to the rotation direction in the other channel. The jets impinged normally on two smooth target walls. Heat transfer results are presented for these two target walls, for the jet walls containing the jet producing orifices, and for side walls connecting the target and jet walls. The flow exited the channels in a single direction, radially outward, creating a cross flow on jets at larger radii. The mean test model radius to jet diameter ratio was 397. The jet rotation number was varied from 0.0 to 0.0028 and the isolated effects of jet Reynolds number (5000 and 10000), and wall-to-coolant temperature difference ratio (0.0855 and 0.129) were measured. The results for non-rotating conditions show that the Nusselt numbers for the target and jet walls in both channels are about the same and are greater than those for the side walls of both channels. However, as rotation number increases, the heat transfer coefficients for all walls in both channels decrease up to 20% below those results which correspond to non-rotating conditions. As the wall-to-coolant temperature difference ratio increases, heat transfer coefficient decreases up to 10% with other parameters held constant.
Development of a Cobalt Base Superalloy for Heavy Duty Gas Turbine Nozzles
Authors: Sato M. , Kobayashi Y. , Matsuzaki H. , Shimomura K. , Shibata T. , Nakamura S. , Fukui Y. , Wada K.
Published: February 2015

This paper describes an improvement in creep strength and thermal fatigue and hot corrosion resistance of a cobalt base superalloy developed for the applications of heavy duty gas turbine nozzles. The developed alloy has superior resistance to creep, thermal fatigue and hot corrosion over that of conventional alloys.

The optimization of alloying elements which improve the creep properties and restrain the coarsening of carbides is discussed. A reduction in the volume fraction of eutectic carbides promoted the prevention of fast thermal fatigue cracking and also increased the hot corrosion resistance of the developed alloy.

The mechanical properties were evaluated by general method for gas turbine materials. Thermal fatigue property was examined by introducing cyclic thermal stress into test pieces. During the test, crack propagation of the test pieces was observed. Hot corrosion resistance was evaluated by molten salt corrosion tests. After tests, mass loss of specimens was measured and penetration depth of sulfidized scale was observed. The developed alloy showed good properties which can allow a wide temperature margin for high temperature gas turbine nozzle designing.

The developed alloy can be applicable to other gas turbine hot sections. Application of the developed alloy could realize an increase in gas firing temperature or extension of lifetime for current conditions.
Modular Approach to Off-Design Gas Turbines Simulation: New Prospect for Reheat Applications
Authors: Carcasci Carlo , Facchini Bruno , Marra Riccardo
Published: February 2015

This paper proposes the application of a modular approach to off-design prediction of multi- and single-shaft gas turbines. The performance effects of some variations of plant configurations are easy to predict. A solution adopted for module matching is shown, and the instability phenomena in some elementary units (i.e. stalling and surge in the compressor) are studied.

The partial load behavior study of aeroderivative gas turbines is presented and performance comparisons are made with a particular heavy-duty advanced application. An analysis example shows some reheat effects in combined power plant applications.

This work enabled the authors to make interesting observations on control techniques and gas-turbine configurations for advanced, combined power-plants. It also shows the wide possibilities of code applications.
Transonic Probe Blockage Effects in a Calibration Wind–Tunnel and Stator Blade Passage
Authors: Truckenmüller Frank , Renner Martin , Stetter Heinz , Hosenfeld Hans–Georg
Published: February 2015

Probe blockage effects are presented for transonic flow through a calibration wind–tunnel as well as through a guide vane row in a three–stage model turbine.

Accurate experimental data from measurements in a transonic turbine are needed for the verification of CFD results. The accuracy of etatic pressure measurements in transonic turbine stages is severely affected by the pressure probe stem disturbing the surrounding flow–field. These disturbance effects are present during calibration procedures in wind–tunnels, as well as during measurements in–between turbomachinery blade rows. Therefore, the phenomenon associated with this blockage effect must be investigated for both procedures.

The influence of the blockage ratios on the static pressure readings of the four–hole wedge probe during the calibration procedure is investigated for two different wind–tunnels. The aim is to measure the blockage effects on the blade passage flow which are produced by a pneumatic pressure probe immersed in the flow between two adjacent blade rows. In order to measure these effects, two stator blades are instrumented with static pressure taps along the blade chord, as well as along the blade span. During the investigations, the radial and circumferential positions of the probes relative to the blade channel are varied. Pressure probe readings of two four–hole wedge probes with different stem diameters are compared as well as correlated to the static pressure readings of the stator blade pressure taps. The apparent deviations of the different readings are discussed.
Analysis of Flow Within Pump Impeller of Torque Converter
Authors: Tsujita Hoshio , Mizuki Shimpei , Ejiri Eiji
Published: February 2015

It is difficult to measure flow patterns within rotating elements of a torque converter due to the complicated construction. Therefore, the numerical calculation is considered to be an effective tool to know the internal flow. Three-dimensional incompressible turbulent flow within a pump impeller of an automotive torque converter was analyzed numerically at three different speed ratios, 0.02, 0.4 and 0.8 under the same inlet boundary condition. The speed ratio was defined as the ratio of rotating speed of the turbine impeller to that of the pump. The governing equations using the k-ε model in the physical component tensor form were solved with a boundary-fitted coordinate system fixed on a rotating impeller. The solution algorithm was the SIMPLE method applied to the curvilinear coordinate system. The computed results were compared with those obtained experimentally by an oil film flow visualization technique for the pressure, suction, core and shell surfaces. Moreover, the results at three different speed ratios were examined in detail in order to clarify the behavior of secondary flow patterns. The computed results showed good agreement with the experimental results and clarified the behavior of the complicated flow patterns. The secondary flow patterns were strongly influenced by the correlation between the intensities of the Corinlis force (COF) and the centrifugal force due to the passage curvature in the meridional plane (CMF).
Turbulence Amplification With Incidence at the Leading Edge of a Compressor Cascade
Authors: Hobson Garth V. , Wakefield Bryce E. , Roberts William B.
Published: February 2015

Detailed measurements, with a two-component laser-Doppler velocimeter and a thermal anemometer were made near the suction surface leading edge of Controlled-Diffusion airfoils in cascade. The Reynolds number was near 700,000, Mach number equal to 0.25, and freestream turbulence was at 1.5% ahead of the cascade.

It was found that there was a localized region of high turbulence near the suction surface leading edge at high incidence. This turbulence amplification is thought to be due to the interaction of the free-shear layer with the freestream inlet turbulence. The presence of the local high turbulence affects the development of the short laminar separation bubble that forms very near the suction side leading edge of these blades. Calculations indicate that the local high levels of turbulence can cause rapid transition in the laminar bubble allowing it to reattach as a short “non-burst” type.

The high turbulence, which can reach point values greater than 25% at high incidence, is the reason that leading edge laminar separation bubbles can reattach in the high pressure gradient regions near the leading edge. Two variations for inlet turbulence intensity were measured for this cascade. The first is the variation of maximum inlet turbulence with respect to inlet-flow angle; and the second is the variation of leading edge turbulence with respect to upstream distance from the leading edge of the blades.
Modeling and Prediction of the Laminar Leading-Edge Separation and Transition in a Blade-Cascade Flow
Authors: Tselepidakis Dimitri P. , Kim Sung-Eun
Published: February 2015

This paper presents the computation of the flow around a controlled diffusion compressor cascade. Features associated with by-pass transition close to the leading edge — including laminar leading-edge separation — contribute significantly to the evolution of the boundary layer on the blade surface. Previous studies have demonstrated that conventional k-ε models, based on linear or non-linear Boussinesq stress-strain relations, are able to capture by-pass transition in simple shear, but are unable to resolve transitional features in complex strain, like the leading-edge separation bubble, which is of considerable influence to the suction-side flow at high inlet angle. Here, the k-ω turbulence model has been implemented in a nonstaggered, finite-volume based segregated Reynolds-Averaged Navier-Stokes solver. We demonstrate that this model, if properly sensitized to the generation of turbulence by irrotational strains, is capable of capturing the laminar leading-edge separation bubble. The real flow around the leading edge is laminar and the transition is only provoked on the reattachment region. Additional investigation of transition in a flat-plate boundary layer development has also produced reasonably promising results.
Experimental Study of a 3D Wake Decay and Secondary Flows Behind a Rotor Blade Row of a Low Speed Compressor Stage
Authors: Witkowski A. S. , Chmielniak T. J. , Strozik M. D.
Published: February 2015

Detailed measurements have been performed in a low pressure axial flow compressor stage to investigate the structure of the secondary flow field and the three-dimensional wake decay at different axial locations before and behind the rotor. The three dimensional flow field upstream and downstream of the rotor and on the centerline of the stator blade passage have been sampled periodically using a straight and a 90 degree triple-split fiber probe. Radial measurements at 39 radial stations were carried out at chosen axial positions in order to get the span-wise characteristics of the unsteady flow. Taking the experimental values of the unsteady flow velocities and turbulence properties, the effects of the rotor blade wake decay and secondary flow on the blade row spacing and stator passage flow at different operating conditions are discussed. For the normal operating point, the component of radial turbulent intensities in the leakage-flow mixing region is found to be much higher than the corresponding axial and tangential components. But for a higher value of the flow coefficient the relations are different.The results of the experiments show that triple-split fiber probes, straight and 90 degree measurements, combined with the ensemble average technique are a very useful method for the analysis of rotor flow in turbomachinery. Tip clearance vortex, secondary flow near the hub and radial flow in the wake, turbulent intensity and Reynolds stresses and also the decay of the rotor wakes can be obtained by this method.
Turbomachinery Multistage Simulation by a Finite Element Adaptive Approach
Authors: Sleiman M. , Robichaud M. P. , Peeters M. F. , Tam A. , Habashi W. G. , Fortin M.
Published: February 2015

This paper presents the application of a three-dimensional Navier-Stokes finite element code (NS3D) in the context of turbomachinery rotor-stator multistage interaction. A mixing-plane approach is used, in which boundary conditions at a common interface plane between adjacent blade rows are iteratively adjusted to yield a flow satisfying the continuity, momentum and energy conservation equations, in an average sense.

To further improve the solutions, a mesh adaptation technique then redistributes the mesh points of the structured grid within each component, according to an a posteriori error estimate based on the Hessian of the local flow solution. This matrix of second derivatives controls both the magnitude and direction of the required mesh movement at each node, which is then implemented using a spring analogy.

The methodology is demonstrated for the second stage compressor of the UTRC large-scale rotating rig at an rpm of 650 and a flow coefficient of 0.51, and for a two-stage compressor of a turboprop engine running at 45,000 rpm. The results compare well to the experimental data and illustrate the potential of the approach.
The Gas Turbine GT26 in Combined Cycle Application: Conversion of a Coal Power Plant Into a Modern Combined Cycle Firing Natural Gas and Oil No. 2
Authors: Scherer Viktor , Scherer Dieter
Published: February 2015

The current paper describes the repowering of an existing coal plant (Rheinhafen Power Station). In this power plant, the hard coat boiler was repleced by a modern once through, Heat Recovery Steam Generator (HRSG). The HRSG is connected to a natural gas or oil fired gas turbine ABB GT26. The plant is located in Karlsruhe, Germany, and is operated by the Badenwerk AG, a public utility. The original hard coal fired plant was put into service in 1964. It is equipped with a steam turbine of approx. 100 MW power output. To maintain the initial steam data of the power plant at 160 bar and 540 °C, and to guarantee a low start-up time, an unfired once through type steam generator was chosen. Minor modifications were done in the steam turbine to increase the maximum steam turbine power output to approx. 124 MW. Combined with the approx. 240 MW power output of the GT26 a total output of 363.5 MW. MW is expected. The efficiency has thus been increased from 38 % for the steam power plant to 58.2% for the combined cycle.
Characterization and Performance Evaluation of Pack Cementation and Chemical Vapor Deposition Platinum Aluminide Coatings
Authors: Mutasim Zaher , Brentnall William
Published: February 2015

Metallurgical evaluation of platinum aluminide coatings applied to industrial gas turbine components, for oxidation and high temperature hot corrosion protection, were conducted. Coatings were processed by electroplating a thin layer of platinum followed by aluminizing using either the pack cementation or the chemical vapor deposition (CVD) processes. Laboratory and field data on the performance of these coatings are presented. Results from these tests showed that both aluminizing processes produced coatings that provided adequate environmental protection. However, the CVD coating experienced less coating growth during engine service and was therefore determined to be thermally more stable than the pack cementation coating in this application.
Hot Wire Measurements During Rotating Stall in a Variable Pitch Axial Flow Fan
Authors: Blanco-Marigorta Eduardo , Ballesteros-Tajadura Rafael , Santolaria Carlos
Published: February 2015

This work deals with a series of experiments on the influence of the blade pitch on the rotating stall phenomenon in an industrial variable pitch, low-speed axial flow fan with low hub-to-tip ratio.

Two simple hot wires were used to detect the rotating stall. One in the absolute frame and the other in the relative frame rotating with the rotor. The rotating stall features were determined, ranging from the non-existence in the whole flow range with the lowest pitch tested to one and two flow cells with the greatest pitch.

Then, a triple hot wire, calibrated by a direct method, was used to measure the absolute flow field upstream and downstream from the rotor, before and during rotating stall for five distinct blade pitches. These measurements allow us to characterize different rotating stall structures.

To understand the phenomena better, some tests were carried out in the relative frame, with the probe rotating with the rotor. An intermediate blade pitch with a single rotating cell was selected and measurements were taken at three radial positions. Velocity maps for all these measurements are presented.
Optimum Mixing for a Two-Sided Injection From Opposing Rows of Staggered Jets Into a Confined Crossflow
Authors: Blomeyer Malte M. , Krautkremer Bernd H. , Hennecke Dietmar K.
Published: February 2015

The injection of jets normal to a crossflow is a key technology for the development of an advanced low NOx gas turbine based on a Rich-Burn/Quick-Quench/Lean-Burn (RQL) combustor. The RQL combustor depends on an efficient quick mix section that rapidly and uniformly dilutes the rich zone products to minimize emissions. Therefore, an experimental investigation of a non-reacting mixing process of jets in a crossflow was conducted. The jets were perpendicularly injected through one stage of opposed rows of circular orifices into a slightly heated crossflow within a rectangular duct. All geometries were tested with staggered arrangements of the centerlines of the opposed jets. The temperature distribution was measured and from that the mixing rate was determined for parametric variations of flow and geometric conditions. In accordance with the application to RQL-combustion, emphasis was put on high momentum flux ratios with high massflow addition. The experimental study provides the data base for a correlation of best mixing depending on geometric conditions for staggered mixing configurations. The correlation presented specifies the optimum momentum flux ratio as a function of the duct height to hole diameter ratio and the relative spacing of the injected jets.
Research and Development of Ceramic Gas Turbine (CGT302)
Authors: Takehara Isashi , Inobe Isao , Tatsumi Tetsuo , Ichikawa Yoshihiro , Kobayashi Hirotake
Published: February 2015

The ongoing Japanese Ceramic Gas Turbine (CGT) project, as a part of the New Sunshine Project funded by the Ministry of International Trade and Industry (MITI), aims to achieve higher efficiency, lower pollutant emission, and multi-fuel capability for small to medium sized gas turbine engines to be used in co-generation systems. The final target of this project is to achieve a thermal efficiency over 42% at a turbine inlet temperature (TIT) of 1350°C.

Under this project, Kawasaki Heavy Industries (KHI) is developing the CGT302 (a regenerative twin-spool CGT). The CGT302 has several unique features as follows: simple-shaped ceramic components, KHI’s original binding system for turbine nozzle segments, stress-free structure using ceramic springs and rings, etc. In addition to these features, a high turbine tip speed and a metal plate fin recuperator were adopted.

At the end of the fiscal year 1994, an intermediate appraisal was carried out, and the CGT302 was recognized to have successfully achieved its target. The CGT302 endurance test at the intermediate stage required 20 hours’ operation of the basic ceramic engine. The actual testing accomplished 40 hours at over 1200°C TIT, which included 30 hours of operation without disassembling. The target thermal efficiency of 30% at 1200°C has almost been reached, 29.2% having been achieved. In 1995 the CGT302 recorded successfully 33.1% at 1190°C of TIT with no trouble.

We will introduce the current status of R&D of the CGT302 and its unique features in this paper.
A Tool for Thermoeconomic Analysis and Optimization of Gas, Steam and Combined Plants
Authors: Agazzani A. , Massardo A. F.
Published: February 2015

The aim of this work is to demonstrate the capability of an original “modular” simulator tool for the thermoeconomic analysis of thermal-energy systems. The approach employed is based on the Thermoeconomic Functional Analysis (T.F.A.) which, through definition of the “functional productive diagram“ and the establishment of the capital cost function of each component, allows the marginal costs and the unit product costs, i.e. the “internal economy“, of the functional exergy flows to be obtained in correspondence to the optimum point.

The optimum design of the system is obtained utilizing a traditional optimization technique which includes both physical structure of the energy system described in terms of thermodynamic variables and cost model (capital cost of the components, maintenance and amortization factors, unit fuel cost, unit electricity cost, etc.).

As an application example to show the practicability of the tool, the thermoeconomic analysis of various complex multi-pressure combined cycles (with or without steam reheating) is carried out. The results are analyzed and discussed in depth.
Sensor Based Analyzer for Continuous Emission Monitoring in Gas Pipeline Applications
Authors: Schubert Paul F. , Sheridan David R. , Cooper Michael D. , Banchieri Andrew J.
Published: February 2015

Continuous emissions monitoring of gas turbine engines in pipeline service have typically been monitored using either laboratory derived instruments (CEMS) or predicted using data from low cost sensors on the engines and algorithms generated by mapping engine performance (PEMS). A new cost-effective system developed under a program sponsored by the Gas Research Institute (Chicago) combines the advantages of both systems to monitor engine emissions in gas transmission service. This hybrid system is a sensor based analyzer which uses a sensor array, including a newly developed NOx sensor, to directly monitor NOx, CO, and O2 emissions at the stack. The gases are measured hot and wet.

The new systems were installed and tested on a gas-fired Rolls Royce Spey turbine engine and on Ingersoll-Rand KVG-410 and Cooper GMVH-10 reciprocating engines in gas transmission service. These systems passed the Relative Accuracy Test (Part B) required under U.S. EPA regulations (40 CFR 60).
Development of a Catalytic Combustor for a Heavy-Duty Utility Gas Turbine
Authors: Dalla Betta Ralph A. , Schlatter James C. , Nickolas Sarento G. , Cutrone Martin B. , Beebe Kenneth W. , Furuse Yutaka , Tsuchiya Toshiaki
Published: February 2015

The most effective technologies currently available for controlling NOx emissions from heavy-duty industrial gas turbines are either diluent injection in the combustor reaction zone, or lean premixed Dry Low NOx (DLN) combustion. For ultra low emissions requirements, these must be combined with selective catalytic reduction (SCR) DeNOx systems in the gas turbine exhaust. An alternative technology for achieving comparable emissions levels with the potential for lower capital investment and operating cost is catalytic combustion of lean premixed fuel and air within the gas turbine. The design of a catalytic combustion system using natural gas fuel has been prepared for the GE model MS9OOIE gas turbine. This machine has a turbine inlet temperature to the first rotating stage of over 1100°C and produces approximately 105 MW electrical output in simple cycle operation. The 508 mm diameter catalytic combustor designed for this gas turbine was operated at full-scale conditions in tests conducted in 1992 and 1994. The combustor was operated for twelve hours during the 1994 test and demonstrated very low NOx emissions from the catalytic reactor. The total exhaust NOx level was approximately 12–15 ppmv and was produced almost entirely in the preburner ahead of the reactor. A small quantity of steam injected into the preburner reduced the NOx emissions to 5–6 ppmv.

Development of the combustion system has continued with the objectives of reducing CO and UHC emissions, understanding the parameters affecting reactor stability and spatial non-uniformities which were observed at low inlet temperature, and improving the structural integrity of the reactor system to a level required for commercial operation of gas turbines. Design modifications were completed and combustion hardware was fabricated for additional full-scale tests of the catalytic combustion system in March 1995 and January 1996. This paper presents a discussion of the combustor design, the catalytic reactor design and the results of full-scale testing of the improved combustor at MS9OOIE cycle conditions in the March 1995 and January 1996 tests. Major improvements in performance were achieved with CO and UHC emissions of 10 ppmv and 0 ppmv at base load conditions.

This ongoing program will lead to two additional full-scale combustion system tests in 1996. The results of these tests will be available for discussion at the June 1996 Conference in Birmingham.
Discharge Coefficient of Turbine Cooling Holes: A Review
Authors: Hay N. , Lampard D.
Published: February 2015

Published information on the discharge coefficient of film cooling holes is classified in terms of the hole geometry, the external flow conditions at inlet and outlet, and the method of evaluation. This may be either theoretical or experimental.

The information is reviewed primarily in the context of its use for evaluating discharge coefficients for conditions not directly covered by published data. It is shown that potential flow analyses can give acceptable accuracy for simple geometries with crossflows, while more complex cases require the use of correlated data which may be incorporated in a range of predictive schemes.

Deficiencies and inconsistencies in the published information are highlighted, and future developments are discussed.
On the Interpretation of Measured Profile Losses in Unsteady Wake-Turbine Blade Interaction Studies
Authors: Hodson H. P. , Dawes W. N.
Published: February 2015

The interaction of wakes shed by a moving bladerow with a downstream bladerow causes unsteady flow. The meaning of the freestream stagnation pressure and stagnation enthalpy in these circumstances has been examined using simple analyses, measurements and CFD. The unsteady flow in question arises from the behaviour of the wakes as so-called negative-jets. The interactions of the negative-jets with the downstream blades lead to fluctuations in static pressure which in turn generate fluctuations in the stagnation pressure and stagnation enthalpy. It is shown that the fluctuations of the stagnation quantities created by unsteady effects within the bladerow are far greater than those within the incoming wake. The time-mean exit profiles of the stagnation pressure and stagnation enthalpy are affected by these large fluctuations. This phenomenon of energy separation is much more significant than the distortion of the time-mean exit profiles that is caused directly by the cross-passage transport associated with the negative-jet, as described by Kerrebrock and Mikolajczak. Finally, it is shown that if only time-averaged values of loss are required across a bladerow, it is nevertheless sufficient to determine the time-mean exit stagnation pressure.
The Optimization of Combined Cycle HRSGs as a Function of the Plant Load Duty
Authors: Dechamps P. J.
Published: February 2015

Natural gas fired combined cycle power plants now take a substantial share of the power generation market, mainly because they can be delivering power with a remarkable efficiency shortly after the decision to install is taken, and because they are a relatively low capital cost option.

The power generation markets becoming more and more competitive in terms of the cost of electricity, the trend is to go for high performance equipments, notably as far as the gas turbine and the heat recovery steam generator are concerned.

The heat recovery steam generator is the essential link in the combined cycle plant, and should be optimized with respect to the cost of electricity. This asks for a techno-economic optimization with an objective function which comprises both the plant efficiency and the initial investment.

This paper applies on an example the incremental cost method, which allows to optimize parameters like the pinch points and the superheat temperatures. The influence of the plant load duty on this optimization is emphasized. This is essential, because the load factor will not usually remain constant during the plant life-time. The example which is presented shows the influence of the load factor, which is important, as the plant goes down in merit order with time, following the introduction of more modern, more efficient power plants on the same grid.
Test Technics and Evaluation Requirements for Marine Gas Turbine Air Inlet Systems
Authors: Harris Howard , Piñeiro Iván , Oswald Alan
Published: February 2015

This paper discusses the Naval Surface Warfare Center, Carderock Division, Ship Systems Engineering Station (NSWCCD-SSES) test facilities and techniques to evaluate air inlet filtration systems and foreign object damage (FOD) screens, for marine gas turbines. The first section of this paper will detail the air inlet filtration test program. The second section will present the FOD screen test program. Both sections will include instrumentation, measurement techniques, data acquisition system and evaluation criteria to evaluate gas turbine inlet system.
Transonic Stall/Choke Flutter Analysis of Cascades by a Navier-Stokes Solution-Adaptive Approach
Authors: Hwang C. J. , Fang J. M.
Published: February 2015

In this paper, the stall and choke flutter analyses of NACA 0006 unstaggered cascades in transonic viscous flows are presented by using a time domain approach. For the present time domain approach, a solution-adaptive finite volume method with rigid-deformable dynamic mesh treatment is adopted to solve the two-dimensional unsteady Navier-Stokes equations. The structural model equations, where each blade is treated as a typical section having plunging and pitching degrees of freedom, are integrated to obtain the blade displacements by an explicit four-stage Runge-Kutta scheme. In the present calculations, the Baldwin-Lomax turbulence model and two transition formulations are used. The instantaneous meshes, vorticity contours, pressure contours and velocity vectors around the trailing edge clearly indicate the flow phenomena, such as the vortex shedding and λ shocks with separation bubbles. From the histories of blade displacements and total energy, the flutter phenomena are studied. Furthermore, the Fast Fourier Transformation (FFT) and modal identification techniques are introduced to investigate the aeroelastic behaviors in present transonic stall and choke flutter problems.