bluuebunny/crossref_metadata_2025_split huggingface dataset:
Part Load Performance of Chemically Recuperated Gas Turbine Cycles Compared to Other Advanced Cycles
Authors: Abdallah Hicham , Facchini Bruno , Harvey Simon 
Published: December 2014

A number of different innovative gas turbine cycles are currently being developed for future high performance power generation applications. Of particular interest are new cycles such as the Humid Air Turbine (HAT) cycle and the Chemically Recuperated Gas Turbine (CRGT) cycle. The HAT cycle has reached the stage of commercial demonstration, whereas the CRGT cycle is still in the research stage.
Performance predictions for CRGT cycles show cycle performance levels higher than those of the basic Steam Injected (STIG) cycle, but lower than those of state-of-the-art combined cycles. Thus, CRGT cycles are most likely to be of interest for intermediate load operation or cogeneration. For such applications, part load performance is a key performance criterion. Part load operation is generally detrimental to power plant performance, and it is thus important to assess the part load performance of such a plant under various operating conditions. The emphasis of this paper is on the comparison of part load performance of various advanced cycles (STIG, CRGT, Combined Cycle). The results show that the part load performance levels of a CRGT cycle deteriorate less fast than those of a combined cycle, whereas part load behavior is similar to that of a STIG cycle. However, this study also indicates that CRGT part load performance is less attractive than published performance curves of Westinghouse’s innovative CHAT cycle, thus confirming that the key advantage of the CRGT cycle is the projected ultra-low emissions characteristics of the cycle.
Jet Mixing in a Slot
Authors: Wang Ting , Chintalapati Sekhar , Bunker Ronald S. , Lee Ching Pang 
Published: December 2014

Jet mixing inside a slot has the potential to be applied for cooling in various components in gas turbines. Based on the premise that more uniform flow at the exit of the slot would achieve more uniform cooling downstream of the slot, an experimental program was conducted to focus on investigating the flow mixing behavior inside the slots. Various parameters including orientation angle, inclination angle, slot width, effect of primary flow and slot depth were systematically examined.
An array of seven jets with a jet-to-jet spacing of five diameters and velocity ratio of unity was used in the experiment. Experiments were performed by changing the orientation angles of the jets with two inclination angles (90° and 30°). The results indicated that the flow distribution at the slot exit becomes more uniform as the orientation angle was increased from 0° to 60°. Wider slot width brought about high non-uniformity and was clearly undesirable. The optimum slot depth was found to range from 2 to 2.8 times the jet diameter for slots perpendicular to the primary flow (i.e. with 90° inclination angle). The flow field was the most uniform where the shear layers of the two adjacent jets met. Regions of low velocity and high pressure caused non-uniform velocity distribution downstream where the jets met, so deeper slots do not necessarily render better uniformity. When the orientation angle increased from 0 to 30° and 60°, the jets bent toward the wall in the inclined direction caused by the Coanda effect. The presence of the primary flow forced the jet to spread faster in the lateral direction and caused some nonuniform flow pockets at the slot exit.
The compound angle configuration (60° jet orientation and 30° slot inclination angles) was discovered as the best choice with four merits: (i) The acceptable uniform flow can be reached as shallow as h/d = 1.0 (slot depth over jet diameter), (ii) The range of the acceptable uniform flow was the broadest (form y/d = 1.0 to y/d = 2.8). (iii) Flow uniformity was the best at the exit, (iv) The total pressure loss was the lowest.
Highly Resolved Distribution of Heat Transfer for Turbine Leading Edge Film Cooling Including Reynolds Number and Blowing Rate Effects
Authors: Jung K. , Hennecke D. K. 
Published: December 2014

The effect of leading edge film cooling on heat transfer was experimentally investigated using the naphthalene sublimation technique. The experiments were performed on a symmetrical model of the leading edge suction side region of a high pressure turbine blade with one row of film cooling holes on each side. Two different lateral inclinations of the injection holes were studied: 0° and 45°. In order to build a data base for the validation and improvement of numerical computations, highly resolved distributions of the heat/mass transfer coefficients were measured. Reynolds numbers (based on hole diameter) were varied from 4000 to 8000 and blowing rate from 0.0 to 1.5. For better interpretation, the results were compared with injection-flow visualizations.
Increasing the blowing rate causes more interaction between the jets and the mainstream, which creates higher jet turbulence at the exit of the holes resulting in a higher relative heat transfer. This increase remains constant over quite a long distance dependent on the Reynolds number. Increasing the Reynolds number keeps the jets closer to the wall resulting in higher relative heat transfer. The highly resolved heat/mass transfer distribution shows the influence of the complex flow field in the near hole region on the heat transfer values along the surface.
Multistage Centrifugal Compressor Surge Analysis: Part I — Experimental Investigation
Authors: Arnulfi G. L. , Giannattasio P. , Giusto C. , Massardo A. F. , Micheli D. , Pinamonti P. 
Published: December 2014

This paper reports an experimental investigation on centrifugal compressor surge. The compression system consists of a four-stage blower with vaned diffusers and a large plenum discharging into the atmosphere through a throttle valve. Measurements of unsteady pressure and flow rate in the plant, and of instantaneous velocity in the diffusers of the first and fourth compressor stage are performed during deep surge, at several valve settings and three different rotation speeds. Additional tests have been carried out on a different system configuration, i.e., without plenum, in order to obtain the steady-state compressor characteristics and to collect reference data on stall in surge-free conditions. In this configuration, a fully developed rotating stall was detected in the compressor diffusers, while during surge it affects only a limited part of the surge cycle.
The goal of the present experimental work was to get a deeper insight into unstable operating conditions of multi-stage centrifugal compressors and to validate a theoretical model of the system instability to be used for the design of dynamic control systems.
IGV-Rotor Interactions in a 4-Stage Axial Compressor
Authors: Puetz O. , Eikelmann J. , Stoff H. 
Published: December 2014

Detailed experiments have been made in a 4-stage axial compressor of industrial design. The exit flow field of the rotor of the first stage was measured by hot-wire anemometry and fast-response pressure probes under design operating conditions. Tandem inlet guide vanes (IGV) are situated upstream of the first rotor.
Flow field results are presented for total pressure, massflux and swirl angle over a closely-spaced grid of probe locations in radial and circumferential directions in the absolute and rotating frame of reference. The tandem inlet guide vane row and stage 1 vane row are positioned peripherally for various settings (clocking).
Depending on the peripherical position of IGV and stator 1 the mean values for one rotor pitch varies by 1.5% for mass flow, 1.3° for swirl angle and 8.7% for total pressure.
Loss in total pressure at the rotor exit is a minimum, when the IGV row wakes enter the downstream rotor passage at about 1/4 pitch from the suction-side. Blade and vane channels have similar pitchwise spacing.
Modular Simulation of Coolant Internal Network and Rotating Cavity Analysis
Authors: Carcasci Carlo , Carnevale Ennio , Facchini Bruno , Ferrara Giovanni 
Published: December 2014

The increase in gas turbine performance requires very high total inlet temperatures even in heavy-duty applications. Therefore, an accurate design of both the blade cooling and the cooling network from the compressor to the blade is very important. In previous works, the authors have studied the cooling blade problems for both the stator and the rotor case. The present paper presents a simple and fast procedure to study the cooling network: a modular code has been developed for this purpose and particular attention has been focused on the study o the rotating cavities between the stator and the rotating disks.
The results we have obtained are good and the code developed is at present used in industry.
Italian Navy Application, Operation and Maintenance of Fiat - GE LM2500 Gas Turbine Propulsion Systems
Authors: Maggini Massimo , Tonelli Roberto 
Published: December 2014

The LM2500 gas turbine has been used in Italian Navy (ITN) ships for more than twenty years, as the first engines were installed on board the “Lupo” class Frigates during the second half of the 1970s.
The LM2500 during its service has proven to be reliable in both the “Combined Diesel or Gas” (CODOG) and the “Combined Gas and Gas” (COGAG) propulsion plant, with Controllable Pitch Propeller (CPP) and Fixed Pitch Propeller (FPP) as the ITN marine operational experience demonstrates. The last application was in the DURAND DE LA PENNE Class DDG with a CODOG arrangement and two shaft lines with Feathered Controllable Pitch Propellers (FCPP), produced by FINCANTIERI shipyard, which may range from a forward to an astern direction till the blades reach a flag position. This type of propeller allows a considerable drop in the absorbed power and therefore in fuel consumption and noise when using a single shaft.
Based on the ITN experience with the DDG class, the use of FCPP achieves remarkable fuel savings with the gas turbine since, due to the high specific consumption of the engine at low speeds, it is cheaper to have a single shaft running.
The maintenance approach to the engines installed on board ITN ships, based on the “on condition” concept, has been developed by the ITN and Fiat Avio to maximise the availability of the vessels. This covers both on-board corrective maintenance (inspection, special maintenance and / or introduction of improvements) and the substitution maintenance, with successive overhaul and application of decided updating of gas generators and power turbines.
A Novel Optimisation Method for Variable Cycle Jet Engines
Authors: Oggero Lorenzo , Pilidis Pericles 
Published: December 2014

A variable cycle engine (VCE) is a very complex concept. Extensive variable geometry features are required to ensure safe handling characteristics in the two or more operating modes that are envisaged. These may include variable compressor staters, variable nozzle areas and variable bypass valves.
In this paper a method for assessing the optimum setting of control variables is described. The starting point of the analysis is one of the operating modes of the engine, and an optimisation is carried out to decide the new values of the control variables within that operating mode or when changing to another.
The sensitivity of the cycle, in the initial mode, is assessed and an influence coefficient vector is created. This is then employed to decide what setting changes should be implemented to the control variables to achieve the desired result, respecting operating constraints such as surge margins, gas temperatures and rotor speeds.
The engine selected for analysis is the selective bleed engine, although the method could be used for other engine geometries after suitable adaptation. There are two very useful features of this method. The first is that it can give a view of the variable cycle capabilities of an engine with variable geometry features. The second is that it identifies the constraints, enabling the designer to focus the development effort where it is most needed.
CHAT Technology: An Alternative Approach to Achieve Advanced Turbine Systems Efficiencies With Present Combustion Turbine Technology
Authors: Nakhamkin Michael , Swensen Eric C. , Scheibel John R. , Cohn Arthur 
Published: December 2014

This paper describes the current status and anticipated improvements in the Cascaded Humidified Advanced Turbine (CHAT) technology. With these improvements, CHAT will provide an alternative approach to achieving the goals of the Department of Energy’s Advanced Turbine Systems (ATS) project of a 60% thermal cycle efficiency for natural gas fired combined cycle power plants.
The traditional approach to increasing the efficiency of simple cycle and combined cycle power plants was to increase the firing temperature and pressure of the basic Brayton cycle. However, every increase in the CT firing temperature required progressively higher development cost, associated with new materials and cooling techniques, and increased NOx control challenges.
CHAT is a gas turbine based cycle with intercooling, reheat, recuperation and humidification. It is based upon the integration of an existing design heavy duty combustion turbine with an additional high pressure shaft comprised of industrial compressors and expander. The current CHAT plant design includes an HP expander inlet temperature of 871 C (1600 F), which represents the level of the combustion turbine technology of the late 1960’s – early 1970’s. The expander on the power generation shaft (LP) is based upon current combustion turbine technology with turbine inlet temperature of 1400 C (2550 F). One of the most effective ways to increase the CHAT plant efficiency is to increase the HP expander inlet temperature. By increasing this temperature to a relatively low 1150 C (2100 F), and maintaining the current inlet temperatures on the LP expander, the CHAT plant could achieve the ATS program target efficiency.
The paper presents the current CHAT plant’s performance and cost characteristics, and the initial findings of a project co-sponsored by the Electric Power Research Institute (EPRI) and Energy Storage and Power Consultants, (ESPC) for the development of an HP expander with increased inlet temperatures.
Exergy Analysis of Two Second-Generation SCGT Plant Proposals
Authors: Corti A. , Failli L. , Fiaschi D. , Manfrida G. 
Published: December 2014

Two different power plant configurations based on a Semi-Closed Gas Turbine (SCGT) are analyzed and compared in terms of First and Second Law analysis. SCGT plant configurations allow the application of CO2 separation techniques to gas-turbine based plants and several further potential advantages with respect to present, open-cycle solutions. The first configuration is a second-generation SCGT/CC (Combined Cycle) plant, which includes inter-cooling (IC) between the two compression stages, achieved using spray injection of water condensed in a separation process removing vapor from the flue gases. The second configuration (SCGT/RE) combines compressor inter-cooling with the suppression of the heat recovery steam generator and of the whole bottoming cycle; the heat at gas turbine exhaust is directly used for gas turbine regeneration.
The SCGT/CC-IC solution provides good efficiency (about 55%) and specific power output figures, on account of the spray inter-cooling; however, with this configuration the cycle is not able to self-sustain the CO2 removal reactions and amine regeneration process, and needs a substantial external heat input for this purpose.
The SCGT/RE solution is mainly attractive from the environmental point of view: in fact, it combines the performance of an advanced gas turbine regenerative cycle (efficiency of about 49%) with the possibility of a self-sustained CO2 removal process. Moreover, the cycle configuration is simplified because the HRSG and the whole bottoming cycle are suppressed, and a potential is left for cogeneration of heat and power.
A Comparison of Experimental With Computational Results in an Annular Turbine Cascade With Emphasis on Losses
Authors: Casciaro C. , Treiber M. , Sell M. , Saxer A. P. , Gyarmathy G. 
Published: December 2014

Recent discussions in the industrial CFD community have identified a need for guidelines covering the accurate and efficient computation of a range of flow field classes. This paper addresses some of these issues for a standard turbomachinery test case, by investigating the flow through on annular blade row of a generic turbine profile, operating at an exit Mach number of 0.5.
The joint experimental and CFD works have focused upon identifying and quantifying the loss sources and loss development. This has been achieved by the acquisition of dense data sets of a known, high and repeatable experimental accuracy, where, concentrating primarily upon the investigation of the secondary flow phenomena, optimised experimental methods have been employed to measure the pressure distributions in the annuls and the development of the flow field, particularly the loss structures, downstream of the trailing edge.
On the CFD side, the flow field has been computed using commercial codes. Adopting the loss distribution as a primary marker for the quality of the CFD results, the performance and efficacy of the codes and the implemented viscous models can be assessed. The flow has been computed both 2D and 3D, from inviscid to laminar to turbulent with different turbulence models, with and without transition. According to the model, the flow has been investigated considering a wide range of parameters influencing its turbulent state.
Through this study, guidelines concerning numerical smoothing and free-stream turbulence parameters are proposed for the computation of such flows. The need of a transition model within 3D schemes, rather than an improvement of the turbulence model, to predict accurate loss levels has been recognized. However, through the cross analysis of the different computational results, a good estimate of the loss magnitude and distribution is feasible with the currently used models.
Aerodynamic Performance of an Axial Compressor Stage With Variable Rotor Blades and Variable Inlet Guide Vanes
Authors: Cyrus Václav 
Published: December 2014

Experimental investigations of flow fields and losses in an axial flow compressor stage were carried out. The stage has hub/tip ratio of 0.7. The design values of flow coefficient and pressure coefficient are 0.6 and 0.81, respectively. Aerodynamic performance was investigated for two principal configurations: i) axial flow stage with variable rotor blades, ii) axial flow stage with variable inlet guide and stator vanes. The most efficient volume flow rate regulation of the stage was with the application of variable rotor blades.
On the basis of experimental data an analysis of the origin of flow separation on the suction and pressure surfaces of rotor and stator blades was made with the use of simple design criteria. The unsteady flow of rotating stall type in the tested stage appeared after simultaneous occurence of large stall regions in both rotor and stator blade rows. The existence of large stall regions in the IGV did not affect the rotating stall onset. At high values of the IGV stagger angle change (50 deg) pressure pulsations appeared due to the occurence of stall.
Performance Analysis in a Subsonic Radial Diffuser
Authors: Casartelli E. , Saxer A. P. , Gyarmathy G. 
Published: December 2014

Steady-state numerical investigations in a subsonic vaned radial diffuser are presented. The 3D flow field has been computed with a commercial Navier-Stokes code (TASCflow), using two different types of axially variable but circumferentially uniform inlet flow conditions, one based on realistic (measured) time-averaged impeller outflow, the other on an idealized distribution. Two different vane leading-edge shapes were investigated. The leading edge redesign is based on the 2D analysis and inverse-design software package MISES.
For a complete operating speed line a detailed analysis of the flow structure and loss distribution within the diffuser is presented and the results obtained for the different inlet flow conditions and geometries are critically compared. The performance of the diffuser and its subcomponents is evaluated in terms of dimensionless quantities such as blockage, total-pressure-loss and pressure-recovery coefficients. Based on the comparisons and the cross performance analysis of the various effects due to leading edge redesign and different inlet velocity profiles, several design guidelines are postulated.
Ceramic Stationary Gas Turbine Development Program — Fifth Annual Summary
Authors: Price Jeffrey R. , Jimenez Oscar , Faulder Les , Edwards Bryan , Parthasarathy Vijay 
Published: December 2014

A program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technologies, to improve the performance of stationary gas turbines in cogeneration through the selective replacement of metallic hot section components with ceramic parts. The program focuses on design, fabrication, and testing of ceramic components, generating a materials properties data base, and applying life prediction and nondestructive evaluation (NDE). The development program is being performed by a team led by Solar Turbines Incorporated, and which includes suppliers of ceramic components, U.S. research laboratories and an industrial cogeneration end user.
The Solar Centaur 50S engine was selected for the development program. The program goals included an increase in the turbine rotor inlet temperature (TRIT) from 1010°C (1850°F) to 1121°C (2050°F), accompanied by increases in thermal efficiency and output power. The performance improvements are attributable to the increase in TRIT and the reduction in cooling air requirements for the ceramic parts. The ceramic liners are also expected to lower the emissions of NOx and CO.
Under the program uncooled ceramic blades and nozzles have been inserted for currently cooled metal components in the first stage of the gas producer turbine. The louvre-cooled metal combustor liners have been replaced with uncooled continuous-fiber reinforced ceramic composite (CFCC) liners. Modifications have been made to the engine hot section to accommodate the ceramic parts.
To-date all first generation designs have been completed. Ceramic components have been fabricated, and are being tested in rigs and in the Centaur 50S engine. Field testing at an industrial co-generation site was started in May, 1997. This paper will provide an update of the development work and details of engine testing of ceramic components under the program.
Project Optimisation and Construction of Cogeneration Power Plant for a Large Refinery and Petrochemical Complex in India
Authors: Sheikh Ali , Rozewicz Joseph , Kadkol R. V. 
Published: December 2014

Configuration and design of cogeneration power plant supplying 374 MW electric power and 1500 t/h process steam for a new Reliance Jamnagar Refinery and Petrochemical Complex have been optimised on the basis of (i) reliability of power and steam supplies, (ii) fuel availability, (iii) capital and operating cost, and (iv) synergy between the refinery and petrochemical complex, and power plant start-up schedules.
The basic equipment of the power plant consists of 8 Gas Turbines of average site rated power output 31.7 MW per unit, 4 Steam Turbines of 30 MW power output each, 8 HRSG with supplementary firing each having capacity of 125 t/h and 4 conventional Steam Generators of capacity 125 t/h each. The steam generation parameters are: pressure 113.8 bar and temperature 510 °C. The cogeneration power plant also supplies for the refinery complex high pressure steam and intermediate pressure steam extracted from steam turbines.
An analysis of various normal and upset operating scenarios of the refinery complex was carried out to achieve optimal selection of the equipment ensuring the required steam and power supply.