bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mission Design Drivers for Closed Brayton Cycle Space Power Conversion Configuration
Authors: Baggenstoss William G. , Ashe Tom L. 
Published: March 2015

Future space power requirements will vary from the subkilowatt range for deep space probes, to the hundreds of kilowatts range for a lunar base, to the multimegawatt range for interplanetary propulsion systems. Closed Brayton cycle (CBC) power conversion has the flexibility to be used in all these power ranges and with a variety of heat source options such as isotope, solar, and nuclear. Each of these types of heat sources has different characteristics that make it more appropriate for particular mission profiles and power output ranges. Heat source characteristics can also be major design drivers in the closed Brayton cycle design optimization process.
This paper explores heat source selection, the resulting CBC system designs, and discusses optimization methods as a function of the main design drivers. Such power system requirements as power level, man-rated radiation shielding, fuel costs, eclipse/darkness duration, system mass, radiator area, reliability/mission duration, and insolation level are evaluated through several CBC parametric case studies. These cases include:
(1) A 500 We power system for deep space probes,
(2) A 50 kWe solar dynamic system for earth orbit and other applications,
(3) A 100 kWe man-rated lunar/Mars stationary/rover power system,
(4) A 200 to 825 kWe power system for the lunar outpost, and
(5) 3300 kWe modules for interplanetary propulsion.
Experiments on the Blade Loss Transient Response of Rotor With Flexible Damped Support
Authors: Li Qihan , Zhang Shiping , Yan Litang , Zhao Fuan 
Published: March 2015

The purpose of this paper is to present some experimental results on the transient response dynamics of a rotor system with flexible damped support due to the event of simulated blade loss.
Experiments under different sudden unbalances applied on the rotor system with various SFD film clearances at different rotational speeds were performed. The instability conditions characterized by limiting circle orbits for large amplitude at damper location were determined and some special phenomena such as lock up, bistable jump and subharmonic etc. have been observed. The effectiveness and the capability of SFD for suppressing instability are analyzed.
The Influence of Shock Waves on the Viscous Flow Field of Axial Compressors
Authors: Kaldellis J. K. , Katramatos D. T. , Ktenidis P. D. 
Published: March 2015

Changes in flow field due to the presence of shock waves in axial compressors are examined in the present work. A simple but realistic model is used to predict the static pressure, the relative Mach number, the total pressure and the total temperature distributions through the shock region. These distributions are strongly affected by the interaction between the shock waves and the shear layers or the secondary flow field.
Our well documented secondary flow code along with our fast compressible shear layer calculation method are utilized in order to provide the necessary quantities of the viscous flow for the approximate shock-viscous flow interaction procedure. The shock induced losses, along with the increased shear layer or secondary flow losses, are also predicted.
The complete procedure is successfully applied to several test cases including separation. The results of the proposed method are compared with results of previous calculations and the available experimental data.
Finally, the flow field through the rotor of a supersonic compressor is thoroughly analyzed, and major conclusions concerning the modification of the secondary flow field due to the shock wave appearance are given.
Development of a Repair for the Annulus in a Radial Turbine Wheel
Authors: Rose Daniel P. , Price George , Milidantri Thomas 
Published: March 2015

The Garrett GTCP85 engine is used to provide electrical power and compressed air for commercial aircraft, including the Boeing 727 and 737, and the McDonnell Douglas DC-9 and MD-80. The turbine section of this engine consists of a radial flow turbine rotor and stationary nozzle shroud. The turbine rotor configuration on some of the engine models is a two-piece separable assembly, consisting of a wheel which is joined to an exducer. These components are mechanically joined by pressing a crush ring into annulus grooves located on the mating faces. Wear of the annulus necessitates replacement of a significant quantity of the wheels during repair of the turbine rotor assemblies.
This paper discusses the development and evaluation of a repair for the annulus in the radial turbine wheel. The repair process includes heat treatment of the turbine wheel, machining the worn groove, buildup of the groove location with weld, age heat treatment, machining, and inspection. The evaluation includes microstructural examination of the repaired area, mechanical property testing of specimens from repaired wheels, and component testing of a repaired turbine rotor assembly.
In-Situ Soot Measurements in an Operating Engine Gas Turbine Combustor
Authors: Koch R. , Wittig S. , Feld H.-J. , Mohr H.-J. 
Published: March 2015

The dispersion quotient method, an optical measuring technique for particles, has been applied to in situ measurements of the soot particle size and density in the secondary zone of a KHD GT-216 gas turbine combustor under operating engine conditions. The optical technique, which has been developed at the Institut of Thermische Strömungsmaschinen, is based on the light extinction at different wavelength by a particle cloud due to absorption and scattering. It is of particular advantage in applications, where particles of small size (d ≤ 1.0μ) and high density are to be investigated.
In the present investigation, two idling running conditions of the turbine have been studied: 30.000 rpm and 47.000 rpm. The results show, that the dispersion quotient method is well suited for soot measurements in pressurized flames. In particular, it was found, that the soot particle diameter is not effected by the rotating speed of the turbine. The size of the soot particles was always in the range from 0.1 to 0.3 mircon. The soot volume fraction, however, was found to be strongly influenced by different rotating speeds, with higher rotating speed causing higher volume fraction of soot.
Acoustic Emission Evaluation of Thermal Barrier Coatings Using the Three Point Bending Test
Authors: Verbeek A. T. J. , Houben J. M. , Klostermann J. A. 
Published: March 2015

Thermal Barrier coatings were tested in three point bending tests, combined with acoustic emission evaluation.
The test specimens consist of a 2 mm substrate with a 0.1 mm FeCrAlY bondcoat and a 0.3 mm ZrO2/Y2O3 93/7.8 weight % topcoat. Both the topcoat and the bondcoat were air plasma sprayed under varying conditions of the substrate cooling and the length of the plasma flame.
On investigating the microstructure of the coatings, using light and electron microscopy, differences could be observed, due to the various spraying techniques.
The coated specimens were tested in a tensile testing machine equiped with a special tool for three point bending tests. During bending, acoustic emissions from the coating were measured, using a two channel acoustic emission apparatus. Two types of AE sensors were used, namely a 150 kHz resonance sensor and a 0.1 −1 MHz wide band sensor.
The various coatings show different AE patterns, especially the bondcoats which showed differences according to the spraying techniques.
The use of wide band sensors had some advantages, however they were less sensitive than resonance sensors, they take signals that were received by the resonance ones.
After testing, the specimens were prepared and microscopically investigated. Herewith it was possible to establish a relationship between the measured AE signal and the type of coating and coating failure.
Phase Shift Torquemeters for Gas Turbine Development and Monitoring
Authors: van Millingen R. D. , van Millingen J. D. 
Published: March 2015

Multipole phase shift torquemeters now measure shaft power to 0.1% accuracy in R & D applications, and to 1.0% when designed for permanent installation, both at confidence levels of 95%.
The total installed power to date is 2 million kW, and over 2 million hours have been logged with good reliability. They are in service at speeds up to 90,000 RPM and powers of 50MW.
The paper outlines ways of ensuring credibility, and describes typical designs for R & D use, and for permanent installation. It concludes that the application problems are largely those of transmission engineering.
An Integrated Gas Turbine-Kalina Cycle for Cogeneration
Authors: Olsson E. , Desideri U. , Stecco S. S. , Svedberg G. 
Published: March 2015

A number of studies have shown that the Kalina cycle, using an ammonia-water mixture, can reach higher efficiencies than the normal steam Rankine cycle. In this paper, the Kalina cycle, with a gas turbine topping cycle is applied to cogeneration for district heating. Since the district heating temperatures vary with the heat demand over the year, this application may prove to be especially suitable for the Kalina cycle with its many degrees of freedom in the condensation system.
A theoretical comparison between different bottoming cycles producing heat for a typical Scandinavian district heating network has been carried out. The Kalina cycle, the Rankine cycle with a mixture of ammonia and water as the working fluid and the normal single pressure steam Rankine cycle are compared. It is shown that a simple Rankine cycle with an ammonia-water mixture as the working fluid produces more heat and power than the steam Rankine cycle. The best results, however, are obtained for the Kalina cycle, which generates considerably higher heat and power output than the steam Rankine cycle.
A Coal-Water Slurry Combustor for a 5MW Industrial Gas Turbine
Authors: Wilkes C. , Santanam C. B. 
Published: March 2015

This paper summarizes 1/10 scale combustor test results and design parameters that have lead to the fabrication, assembly and test of a full-scale, 22 MW thermal-input (76 mmbtu/hr) combustor and engine system. The engine is a production Allison 501-K industrial turbine that has been modified to accept an external combustor designed for burning coal-water-slurry (CWS) fuel. The combustor utilizes rich-quench-lean (RQL) staging to control emissions of both thermal NOx and NOx formed from nitrogenous compounds contained in the coal-water slurry. Water is injected into the quench zone to freeze molten ash that is formed in the rich zone. The dry ash is removed from the system and collected in storage vessels by passing the hot combustion products through parallel cyclone separators. The cleaned fuel-rich gases pass to the lean zone where the addition of compressor-discharge air results in auto-ignition of the gas mixture and provides sufficient oxygen for completion of the combustion reactions.
Measurements made of emissions from the bench-scale combustor at simulated power conditions show that NOx and CO concentrations of less than 50 ppmvd corrected to 15% oxygen can be expected. Check out testing of the full-scale combustor on CWS and the combined combustor/engine assembly on distillate fuel are now in progress. It is anticipated that engine testing on CWS will commence in early 1991.
CFD Analysis of Jet Mixing in Low NOx Flametube Combustors
Authors: Talpallikar M. V. , Smith C. E. , Lai M. C. , Holdeman J. D. 
Published: March 2015

The Rich-burn/Quick-mix/Lean-burn (RQL) combustor has been identified as a potential gas turbine combustor concept to reduce NOx emissions in High Speed Civil Transport (HSCT) aircraft. To demonstrate reduced NOx levels, cylindrical flametube versions of RQL combustors are being tested at NASA Lewis Research Center. A critical technology needed for the RQL combustor is a method of quickly mixing by-pass combustion air with rich-burn gases.
In this study, jet mixing in a cylindrical quick-mix section was numerically analyzed. The quick-mix configuration was five inches in diameter and employed twelve radial-inflow slots. The numerical analyses were performed with an advanced, validated 3-D Computational Fluid Dynamics (CFD) code named REFLEQS. Parametric variation of jet-to-mainstream momentum flux ratio (J) and slot aspect ratio was investigated. Both non-reacting and reacting analyses were performed.
Results showed mixing and NOx emissions to be highly sensitive to J and slot aspect ratio. Lowest NOx emissions occurred when the dilution jet penetrated to approximately mid-radius. The viability of using 3-D CFD analyses for optimizing jet mixing was demonstrated.
The Application of Particle Image Velocimetry (PIV) in a Short Duration Transonic Annular Turbine Cascade
Authors: Bryanston-Cross P. J. , Towers C. E. , Judge T. R. , Towers D. P. , Harasgama S. P. , Hopwood S. T. 
Published: March 2015

A series of experiments have been performed to demonstrate the application of Particle Image Velocimetry (PIV) to turbomachinery flows. The tests were performed at transonic speeds on a fully annular engine size turbine nozzle guide vane. The vane cascade was installed in a short duration Isentropic Light Piston Cascade (ILPC) test facility operating with high inlet turbulence levels.
The technique has been shown to map the whole flow field with a resolution of 0.5 mm. The quality of the results obtained are not significantly affected by local turbulence rates. The accuracy of the measurements is put at around 4% of absolute velocity and is limited by the quality of the image on the film plane.
The velocities derived from the PIV images have been compared with predictions from a three-dimensional viscous numerical calculation. It is shown that the experimental and predicted results are in good agreement. It is considered that this technique has considerable potential in application to turbomachinery flow field diagnostics.
Multikilowatt Lasers in Manufacturing
Authors: Banas Conrad M. 
Published: March 2015

The fundamentals of laser beam interactions with materials are discussed briefly and unique laser processing capabilities are noted. Introduction of this processing capability to manufacturing is reviewed. Typical high volume production application requirements are identified and representative performance and production experience are described.
Specific multikilowatt laser welding, piercing and hardfacing applications in aerospace production are described. Evolution of production processes is discussed against the background of required processing capability. Also discussed are the unique laser processing capabilities which resulted in selection of the laser for production. Production experience is reviewed and cost saving factors are noted.
A Gas Operated Bearing Damper for Turbomachinery
Authors: Vance John M. , Cardon Bradley P. , San Andres Luis A. , Storace Albert F. 
Published: March 2015

A gas operated bearing damper for turbomachinery has been designed, analyzed, and experimentally investigated in the laboratory. The damper utilizes air bled off from the compressor to power an actuator through orifices with area modulated by the vibratory displacement at the bearing support. The design objective for this passive device is to make the actuating dynamic gas pressure phase lead the vibratory displacement by 90 degrees.
Several variations of the basic concept have been tested. An analysis was performed to guide the experiments. All of the designs tested to date can produce positive damping, and one particular design has produced a damping coefficient of 8756 N-s/m (50 lb-sec/in) with a power penalty of 5.2 KW (7 HP) at 310 KPa (45 psi). This design was installed on a laboratory rotor with flexibly supported ball bearings, and significant damping of the critical speed response was demonstrated.
The experimental results to date suggest that further research can produce significant improvements in performance, and the device appears to be especially adaptable to high temperature applications for aircraft engines.
Development Testing of Epicyclic Gearing
Authors: Yates D. E. , Lack G. J. 
Published: March 2015

The increasing use of epicyclics for high powered marine and industrial applications has resulted in world wide interest in this type of gearing. The coaxial input and output, reduced losses, small size and low weight are some of the advantages.
The use of a full size development test rig using the power circulation method has been fundamental to the evolution of double helical, flexible annulus epicyclics, and has led to a detailed understanding of their operating principles. This understanding has been essential for the analytical modelling and the development of innovative design concepts.
The paper outlines some of the work which has been carried out in the test rig at NEI Allen Ltd - Allen Gears. The method of measuring the dynamic load sharing is discussed and some of the results which have led to improvements in the design and manufacturing methods are given.
Test rig work continues currently with the development of low noise gears and vibration isolation.
Development of Ceramic Turbocharger Rotors for High Temperature Use
Authors: Kawase Hiroyuki , Matsuhisa Tadaaki , Kato Kiminari , Mizuno Takeyuki 
Published: March 2015

A ceramic turbocharger rotor (CTR) for high temperature use has been developed. The features of this rotor are the use of silicon nitride which maintains high mechanical strength up to 1,200 °C and a new joining technique between the ceramic rotor and its metal shaft. The CTR is expected to cope with stoichiometrical mixture burning engines which produce a higher exhaust gas temperature for fuel economy, and the impact resistance of the rotor against foreign object damage (FOD) has been markedly increased, over that of earlier rotors, resulting in higher reliability.
This paper describes the development of ceramic turbocharger rotors for high temperature use focusing on the mechanical strength of silicon nitride and the joining of the ceramic rotor and its metal shaft.
MVC-2M Fault Diagnosis System and its Application
Authors: Xu G. P. , Lu W. Z. , Wu X. Q. , Weng W. X. , Ge N. M. , Guo X. Y. , Zhu J. H. , Bian X. J. 
Published: March 2015

The MVC-2M Fault Diagnosis System — an achievement of the national key research task in this field is presented in this article. The system can be used in various fields such as marine power engines, power generation, petrochemical industry, aviation and space, machine building etc. The basic functions of this system include real-time condition monitoring, on-line and off-line fault diagnosis, establishment of operation database, storage of fault data in blackbox, calibration of vibration measuring instruments, analysis of structural dynamic characteristics, local dynamic balancing, and so on.
This article also presents several practical experieces during its term of service in Chinese naval vessels and power stations. It is widely confirmed that the MVC-2M system is essential to forecast the faults which probably would happen and thus is successful for avoiding the serious damage of the machines in motion.
Cascade Testing of Ceramic Vanes for Industrial Gas Turbines
Authors: Tsuji I. , Aoki S. , Miyazaki S. , Hara Y. , Furuse Y. , Hamada S. 
Published: March 2015

The development of uncooled ceramic vanes for a 20MW class gas turbine with the firing temperature of 1300°C is progressing.
The 1st stage ceramic vanes were made of sintered SiC or sintered Si3N4, and the 2nd stage ceramic vanes were made of sintered Si3N4. These vanes were tested by means of hot and high pressure cascade testing simulating actual gas turbines operation.
After minor modifications, we have succeeded in developing sound ceramic vanes which are durable against high thermal stress which occurs during the transient of trip (emergency shutdowns or fuel tripouts), and obtained great results for the practical application.
In this paper, details of the ceramic vanes’ structure and cascade testing are described and the results of the tests are discussed.
A New Base Pressure Correlation for Transonic and Supersonic Flows
Authors: Bölcs A. , Sari O. 
Published: March 2015

This paper presents a new base pressure correlation for transonic and supersonic flow conditions obtained from systematic measurements in linear and annular turbine cascades and by considering the physics of the flow in choked cascades. The correlation is valid in the range from near sonic outlet flow velocity to limit loading.
Most of the presently used base pressure correlations show deviations from experimental results for several profile types. One of the reasons is the uncertainty in the evaluation of the downstream pressure in the cascade used as a reference pressure.
In the model proposed here, another reference value is defined instead, namely the Mach number of the recompression point at the end of the triangular base pressure region. This recompression Mach number is obtained in an indirect way from the measured pressure distribution on the profile, i. e., by applying characteristic relations.
The advantage of this base pressure correlation is that a unique relationship between the base pressure and an arbitrarily defined reference pressure (for example, the back pressure) can be established.
A Non-Dimensional Conceptual Design Procedure for the Vaneless Volutes of Radial Inflow Turbines
Authors: Whitfield A. , Noor A. B. Mohd 
Published: March 2015

The requirements for the volute of a radial inflow turbine are that it should collect the working fluid, deliver it to the turbine rotor as efficiently as possible and provide the desired rotor inlet conditions. The overall performance requirements of the turbine leads to the rotor design and the identification of the desired flow conditions at rotor inlet in terms of the magnitude and direction of the absolute Mach number, see Whitfield (1990). The volute must then be designed to ensure that the desired rotor inlet conditions are attained.
A non-dimensional conceptual design procedure for a vaneless turbine volute is described. Based on a knowledge of the magnitude and direction of the absolute Mach number at rotor inlet the overall dimensions of the volute in terms of the radius ratio and flow area ratio are first established. The overall design is then developed to provide the variation of the volute centroid radius and area ratio with azimuth angle. A trapezoidal cross-sectional shape is then used to establish the outer dimensions of the volute.
The non-dimensional design procedure assumes a one-dimensional compressible flow and as such relies on the empirical specification of the dissipation of angular momentum, the dissipation of energy, and the deviation of the swirling flow from that of a free vortex. The effect of the uncertainties associated with the empirical data on the volute design geometry is assessed.
Combustion of LCV Coal Derived Fuel Gas for High Temperature, Low Emissions Gas Turbines in the British Coal Topping Cycle
Authors: Kelsall G. J. , Smith M. A. , Todd H. , Burrows M. J. 
Published: March 2015

Advanced coal based power generation systems such as the British Coal Topping Cycle offer the potential for high efficiency electricity generation with minimum environmental impact. An important component of the Topping Cycle programme is the development of a gas turbine combustion system to burn low calorific value (3.5–4.0 MJ/m3 wet gross) coal derived fuel gas, at a turbine inlet temperature of 1260°C, with minimum pollutant emissions.
The paper gives an overview of the British Coal approach to the provision of a gas turbine combustion system for the British Coal Topping Cycle, which includes both experimental and modelling aspects. The first phase of this programme is described, including the design and operation of a low-NOx turbine combustor, operating at an outlet temperature of 1360°C and burning a synthetic low calorific value (LCV) fuel gas, containing 0 to 1000 ppmv of ammonia. Test results up to a pressure of 8 bar are presented and the requirements for further combustor development outlined.