bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flow and Heat Transfer in a Ribbed U-Duct Under Typical Engine Conditions
Authors: Shih T. I-P. , Lin Y.-L. , Stephens M. A. , Chyu M. K. , Civinskas K. C. 
Published: December 2014

Computations were performed to study the three-dimensional flow and heat transfer in a ribbed U-shaped duct of square cross section under operating conditions that are typical of industrial gas turbines. Basically, all walls were maintained at a temperature of 800 K, and the coolant air at the duct inlet had a temperature of 550 K and a pressure of 10 atm. Both rotating and non-rotating cases were investigated. When rotating, the angular speed was 3,600 rpm. The Reynolds number based on the duct hydraulic diameter was set at 350,000, which represents an upper limit in coolant flow. The results obtained in this study were compared with those from previous numerical studies with a lower Reynolds number, namely 25,000, which represents a lower limit in coolant flow.
This computational study is based on the ensemble-averaged conservation equations of mass, momentum (compressible Navier-Stokes), and energy. Turbulence is modelled by two low-Reynolds number k-ω models: an SST version with isotropic eddy diffusivity and a nonlinear version with anisotropic eddy diffusivity from an explicit algebraic Reynolds stress model. Solutions were generated by using a cell-centered finite-volume method, that is based on flux-difference splitting and a diagonalized alternating-direction implicit scheme with local time-stepping and V-cycle multigrid.
Gas Turbine Uprating Programme Development and Testing of the GT11NM
Authors: Schneider Christoph , Navrotsky Vladimir , Harasgama Prith 
Published: December 2014

ABB has approximately 200 GT11N and GT11D type gas turbines currently operating in simple cycle and combined cycle power plants. Most of these machines are fairly mature with many approaching the end of their economic life. In order that the power producer may continue to operate a fleet with improved performance, Advanced Air Cooling Technology and Advanced Turbine Aerodynamics have been utilized to uprate these engines with the implementation of a completely new turbine module.
The objective of the uprating program was to implement the advanced aero/cooling technology into a complete new turbine module with:
• Improved power output for the gas turbine
• Increase the GT cycle efficiency
• Maintain or improve the gas turbine RAM (Reliability, Availability & Maintainability)
• Reduce the Cost of Electricity
• Maintain or reduce the emissions of the gas turbine
The GT11NM gas turbine has been developed based on the GT11N which has been in operation since 1987 and Midland Cogeneration Venture (MCV-Midland, Michigan) was chosen to demonstrate the uprated GT11NM. The upate/retrofit of the GT11N engine was conducted in May/June 1997 and the resulting gas turbine - GT11NM has met and exceeded the performance goals set at the onset of the development program.
The next sections detail the main changes to the turbine and the resulting performance improvements as established with the demonstration at Midland, Michigan.
Compatibility of Advanced Power Generation Technologies With the Independent Power Production
Authors: Susta Miro R. , Luby Peter 
Published: December 2014

Traditional philosophy of power producing state-owned utilities has been effected by their anonymous risk-sharing attitude. They needn’t have bothered too much with brand-new technologies. Technological risk with unproved, although excellent nominal performance machinery was born by the end-users.
On the other hand, independent power producers’ (IPP) philosophy is a little bit different. Their attitude is much more effected by risk evaluation. They have pretty good reasons to be risk-averse with technologies lacking a proven operational record. Any failure to obey their contractual liabilities could mean dramatic consequences to them. Consequently, old-fashioned players in the power generation industry may seem to have been pushing industry technical progress more effectively ahead than it would be with modem players - IPPs.
But this is only one side of the coin. Quite opposite reasons for IPPs’ affinity to modern technologies are higher performance parameters which offer better revenues to them, more flexible choice of fuel and prompt readiness to react sensitively to market imbalance and volatilities. Obviously, a hardly-defined, yet sensible equilibrium under which both these trends coexist and inter-act here exists. In this paper we shall analyse factors affecting such equilibrium by presenting real examples of gas turbine-dependent power generation technologies.
Radiation and Convection Heat Flux Sensor for High Temperature Gas Environment
Authors: Martins Nelson , Carvalho Maria da Graça , Afgan Naim , Leontiev Alexander Ivanovich 
Published: December 2014

The heat flux measurement is one of the essential parameter for the diagnostic of thermal systems. In the high temperature environment there are difficulties in differentiating between the convective and radiation component of heat flux on the heat transfer surface. A new method for heat flux measurement is being developed using a porous sensing element. The gas stream flowing through the porous element is used to measure the heat received by the sensor surface exposed to the hot gas environment and to control whether or not the sensing element receives the convection component of the total heat flux. It is possible to define a critical mass flow rate corresponding to the destruction of the boundary layer over the sensing element. With subcritical mass flow rate the porous sensing element will receive both the convective and radiative heat fluxes. A supercritical mass flow rate will eliminate the convective component of the total heat flux. Two consecutive measurements considering respectively a critical and a sub-critical mass flow rate can be used to determine separately the convection and radiation heat fluxes.
A numerical model of sensor with appropriate boundary condition has been developed in order to perform analysis of possible options in the design of the sensor. The analysis includes: geometry of element, physical parameters of gas and solid and gas flow rate through the porous element.
For the optimal selection of the relevant parameters an experimental set-up was designed, including the sensor element with corresponding cooling and monitoring system and high temperature radiation source. Applying the respective measuring procedure the calibration curve of the sensor was obtained. The linear dependency of the heat flux and respective temperature difference of the gas was verified. The accuracy analysis of the sensor reading has proved high linearity of the calibration curve and accuracy of ± 5%.
A New Method for Surge Margin Improvement of Booster Compressors in Modern Aeroengines
Authors: Peitsch Dieter , Kurz Nikolaus , Fiola Roland 
Published: December 2014

The subject of this paper is the development and first analysis of the performance of a new booster bleed valve control logic to improve the surge margin of the booster compressor in the new BR715 turbofan.
The booster compressor is driven by the LP spool of the two spool engine, comprising an aerodynamically tuned system out of fan root and booster compressor. The flow delivered at the exit of the booster compressor must be accepted by the following HP compressor. This matching is not always possible, since the rates of change of the spool speeds during transients behave differently as do pressure rise and mass flow. Hence the transient handling of the booster compressor is difficult with respect to its surge stability. To aid in this situation it is a common practice to position a booster bleed valve after the booster compressor, which passes bleed air into the bypass duct.
The BR715 jet engine takes advantage of a newly developed logic driving this valve. Monitoring input parameters such as spool and flight speeds as well as altitude, the logic provides the capability of appropriately positioning the valve, thereby maintaining an optimum performance of the engine throughout the whole operating range. Furthermore the logic allows for reaction on thrust reverser deployment or more serious events such as surge and foreign object damage.
Much effort has been put into the development of the newly designed transient valve logic, which in its main part is based on the rate of change of the pressure at the exit of the HP compressor. This logic ensures a sufficient surge margin in case of deceleration or reslams of the engine.
A simulation of the logic was set up, connected to a synthesis program for the two spool engine and used for the development. After this basic testing, the logic was implemented in the BR715 engine, which first ran in April 1997. The actual data from basic handling tests performed with this engine were analysed and checked against simulation results. The paper describes the logic in detail and contains first results. They prove a proper working of the logic and show the strong effect of the booster bleed valve.
Comparison of Measurement Data at the Impeller Exit of a Centrifugal Compressor Measured With Both Pneumatic and Fast-Response Probes
Authors: Roduner C. , Köppel P. , Kupferschmied P. , Gyarmathy G. 
Published: December 2014

The main goal of these investigations was the refined measurement of unsteady high-speed flow in a centrifugal compressor by using the advanced FRAP® fast-response aerodynamic probe system. The present contribution focusses on the impeller exit region and shows critical comparisons between fast-response (time-resolving) and conventional pneumatic probe measurement results.
Three probes of identical external geometry (1 fast and 2 pneumatic) were used to perform wall-to-wall traverses close to the impeller exit. The data shown refer to a single running condition near the best point of the stage.
The mass flow obtained from different probe measurements and from the standard orifice measurement were compared. Stage work obtained from temperature rise measured with a FRAP® probe and from impeller outlet velocity vectors fields by using Euler’s turbine equation are presented.
The comparison in terms of velocity magnitude and angle distribution is quite satifactory, indicating the superior DC measurement capabilities of the fast-response probe system.
Simulation of Vortex Shedding in a Turbine Stage
Authors: Sondak Douglas L. , Dorney Daniel J. 
Published: December 2014

Vortex shedding in a turbomachine blade row is affected by the passing of blades in the adjacent downstream blade row, but these effects have not been examined in the literature. A series of flow simulations has been performed to study vortex shedding in a turbine stage, and to quantify the blade interaction effects on the unsteady pressure response.
The numerical issues of spatial order of accuracy and the use of Newton subiterations were first investigated. Second order spatial accuracy was shown to be inadequate to accurately model the shedding frequency response and time-averaged base pressure. For the small time step employed for temporal accuracy, Newton iterations were shown to be unnecessary.
The effects of the adjacent blade row were examined by comparing the shedding frequency response for the stage simulations to the response for isolated cascades. The vane shedding was shown to occur exactly on a series of harmonics of the blade passing frequency for the stage case, compared to a single predominant frequency for the isolated cascade.
Losses were also examined in the wake region. It was shown that close to the trailing edge, losses were mainly due to wake mixing. Farther downstream of the trailing edge, losses were predominantly due to the trailing edge shock wave.
Rotating Stall Control in a High-Speed Stage With Inlet Distortion: Part I — Radial Distortion
Authors: Spakovszky Z. S. , Weigl H. J. , Paduano J. D. , van Schalkwyk C. M. , Suder K. L. , Bright M. M. 
Published: December 2014

This paper presents the first attempt to stabilize rotating stall in a single-stage transonic axial flow compressor with inlet distortion using active feedback control. The experiments were conducted at the NASA Lewis Research Center on a single-stage transonic core compressor inlet stage. An annular array of 12 jet-injectors located upstream of the rotor tip was used for forced response testing and to extend the compressor stable operating range. Results for radial distortion are reported in this paper.
First, the effects of radial distortion on the compressor performance and the dynamic behavior were investigated. Control laws were designed using empirical transfer function estimates determined from forced response results. The transfer functions indicated that the compressor dynamics are decoupled with radial inlet distortion, as they are for the case of undistorted inlet flow. Single-input-single-output (SISO) control strategies were therefore used for the radial distortion controller designs.
Steady axisymmetric injection of 4% of the compressor mass flow resulted in a reduction in stalling mass flow of 9.7% relative to the case with inlet distortion and no injection. Use of a robust H∞ controller with unsteady non-axisymmetric injection achieved a further reduction in stalling mass flow of 7.5%, resulting in a total reduction of 17.2%.
Current Status of the CGT301, Ceramic Gas Turbine
Authors: Taoka Tomoki , Tanaka Shinya , Tatsuzawa Masashi , Sakida Takeshi 
Published: December 2014

CGT301 ceramic gas turbine is being developed under a contract from NEDO as a part of the New Sunshine Program of MITI to improve the performance of gas turbine for co-generation through the replacement of the hot section components with ceramic parts.
CGT301 is a recuperated, single-shaft ceramic gas turbine. We have been developing some unique technologies, such as the “hybrid” rotor, composed of a metal disk and inserted ceramic blades, considering the future applicability to larger gas turbines.
We could attain the good engine performance with the primary type CGT at a TIT of 1,200°C. The reliability of the hybrid rotor was confirmed at a TIT of 1,350°C on the test rig.
We conducted preliminary tests using the primary type CGT to extract the possible problems derived from the higher TIT. Some modifications were made and the engine operation at a TIT of 1,280°C was conducted successfully.
On the basis of those experiences we finished the design and fabrication of the pilot CGT.
This paper presents the progress in the development of CGT301.
Renewable Fuels Turbine Project
Authors: Ali Sy A. , Parks William P. 
Published: December 2014

An increasing demand for efficient and environmentally clean use of biomass and wood waste byproducts as fuel requires major developments in gas turbines. Gas turbines are designed primarily to handle either natural gas or in some cases diesel fuels. Introducing low BTU, contaminants containing biofuels into a gas turbine would require proper understanding of fuel characteristics, combustor capability to burn these fuels, compressor surge margins, and ability of the turbine section to withstand deposition, erosion and corrosion.
Allison Engine Company (Allison), in cooperation with the U.S. Department of Energy and other partners, has initiated a bioturbine development project which would lead to commercialization of a bioturbine to operate on major categories of biofuels. The project will address six key issues:
• Quantify chemical, physical and combustion characteristics of biofuels, gasifiers, and the mass volume
• Conduct emission modeling of existing combustor with low BTU fuels
• Conduct rig tests
• Modify current design of the combustor to handle low BTU fuels
• Evaluate compressor surge margins to handle increased mass flows
• Conduct full scale engine field test
The total cost of this two and a half years project is approximately $8 million. The DOE will contribute over $3 million. Allison and partners will contribute the remaining $5 million.
There is an additional vital task which must be performed, but is not a part of the current project. The capability of the turbine to withstand deposition, erosion and corrosion must also be evaluated in order to protect the turbine, and provide long term, uninterrupted operation of the gas turbine on biofuels.
An important first step is to obtain quantitative data on gasified biofuels, including the contaminants. This information will be used in combustor modeling and to develop rig tests. The combustor will then be modified and made capable of handling these fuels. Allison will use the 601-K engine combustor (similar to the RB211 DLE combustor), and modify its hardware and software as required. The combustor modification will involve modeling, rig test, hardware and software modifications, and final engine test The entire project is expected to be complete during the second half of 1999.
Concurrent with these tasks, Allison will evaluate the options available to increase the capability of engine mass flow due to low BTU fuels. A parallel task of “ruggedizing” the turbine section is also planned. The resulting turbine is expected to be comparable to natural gas fired commercial gas turbines in performance, durability, reliability and major overhaul cycles.
Vibration Measurement Techniques on an Industrial Gas Turbine Rotor Train
Authors: Florjancic Stefan S. , Franklin Wes , Lively Noel 
Published: December 2014

The rotordynamic behavior of an industrial gas turbine rotor train was assessed on site, and the sensitivity to unbalance was quantified. An outline of the measurement procedure is given.
Differential data reduction with test unbalances was undertaken to minimize the influence of measurement uncertainty. A test unbalance was installed for one run and then shifted by 180° for the consecutive run. With differential data, the effective dynamic properties of the rotor - support - system can be estimated more accurately.
A rotordynamic model was used to identify the support system parameters based on measured data. For the analysis, the anisotropic, elliptical vibration orbits were decomposed into two counter-rotating circular orbits, and the support system parameters identified match the originally predicted values well.
The methods of differential data reduction, rotor train mode shape presentation, elliptical orbit decomposition, and the link of measurement to analytical models with parameter definition are described. Examples from on-site measurements are included for illustration.
Large-Scale Handling and Use of Solid Biofuels
Authors: Schmidt Erik Ravn , Clausen Jens Christian , Luxhøi Fritz 
Published: December 2014

Utilising biomass in the CHP production is not without difficulties: the chemical and physical characteristics of the biofuels; corrosion, slagging and fouling; and working environment. An in-situ high-temperature corrosion monitoring test system was successfully developed. Furthermore, activities have been launched to develop a straw pre-processing method separating the aggressive substances from straw.
As a result of the gasification projects (straw, coal-straw, wood chips) it was concluded that it is possible to gasify straw — probably for 100% straw and definitely for 50/50 blends, although with some difficulties — and for wood chips deposit formation was a major obstacle. Further R&D is definitely needed, but with the limited international interest the gasification technology seems to have reached a dead end in Denmark.
Another focal point is the working environment, where care must be taken to limit any potential health hazards resulting from the handling of long-term stored biofuels.
Design Features of Gas Turbine Systems Applied to Floating Production Storage and Off-Loading (FPSO) Vessels
Authors: Waldhelm Chris , Baron Peter 
Published: December 2014

Application of gas turbines in the off-shore oil and gas market has been successful for many years, utilizing both industrial gas turbines, as well as, aeroderivative types. Today, many operators in this market are pursuing the use of converted oil tankers and purpose-built barges — called Floating Production Storage and Off-Loading vessels (FPSO) — and semi-submersible or tension-leg platforms as alternative means of drilling for and production of oil and gas in much deeper waters than before, gaining flexibility of operation and reduced overall costs.
Due to the special requirements of extreme conditions experienced on board a FPSO vessel, each application involves a considerable amount of pre-design to determine the gas turbine package required capability to satisfy needed reliability. Additionally, international and local maritime regulatory bodies and classification societies concurrence/approval generally are required to authorize vessel operation. The intent of the “Code of Construction and Equipment of Offshore Drilling Units” is to recommend design criteria, construction standards, and other safety measures in order to minimize risk to the vessels, platforms, personnel and to the environment.
To incorporate these requirements into a standardized cost effective gas turbine system, this paper outlines the design features of such a package for installation on FPSO vessels.
Transient Analysis of a Small Gas Turbine to be Used in an Evaporative Cycle
Authors: Gustafsson Jan-Olof , von Heiroth Paul , Lindquist Torbjörn 
Published: December 2014

Static process calculations done by various institutions have shown competitive thermal efficiencies for the evaporative cycle, also known as the HAT-cycle, when compared to the combined gas and steam cycle. The cycle seems also attractive from other standpoints such as lower investment costs and excellent part load performance. With this background several companies and organisations in Sweden have jointly started an evaporative gas turbine project.
The participating organisations agreed to design and erect a pilot plant at the Lund Institute of Technology. In co-operation with the Royal Institute of Technology in Stockholm various tests will be performed with the overall goal to verify efficiency improvements and functional performance. The test schedule started with the gas turbine in dry stand alone operation. From this initial phase the process will be developed, first step is the introduction of a recuperator. The final process includes a water circuit and condensing of water vapour in exhaust gases for recycling to the humidifier.
This paper presents a dynamic model of the gas turbine unit with and without the recuperator. Algebraic models are used for the gas turbine components combined with conservation equations in differential forms for volumes. The approximation used for volumes is the lumped parameter model meaning that properties within the volume are uniform. Heat flow between gas and solid structure is included in the recuperator model but is elsewhere neglected. A comparison between measurements and calculations is presented for the gas turbine without recuperator.