bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physics and Chemistry of Ash in Gas Turbines: The HVOF Technique as a Powerful Simulation Tool
Authors: Verdy C. , Coddet C. , Montavon G. , Molière M. , Vierling M. , Sokolov D. 
Published: July 2013

In a real gas turbine the fluid dynamics and the thermal conditions that prevail in the hot gas path and near hot parts walls are rather complex. This type of machine features indeed a very specific set of operating conditions, including: high gas temperatures and velocities, complex gas streamlines combined with a wide range and fast variability of operation load. The artifacts caused by internal cooling devices and thermal barriers or anti-corrosion coatings add to this complexity. For these reasons, predicting the fate of ash particles approaching or impinging a hot part represents a real challenge.
In addition the particular conditions that prevail in the combustors, especially: the pressurized and very oxidizing flames, the high temperature but short residence time, make the chemistry of ash formation fairly complex as well.
A work recently undertaken by GE Energy and LERMPS shows that HVOF (High Velocity Oxy-Fuel) facilities represent interesting tools to simulate the “in-flame generation” of ash particles and their fate when impinging on a part wall, provided the test conditions, especially the thermal and velocity fields, are properly adjusted and controlled.
The paper summarizes the development of HVOF experiments specifically devised to study the formation of ash particles with controlled chemistry and their deposition onto hot parts.
Determination of Steady State Gas Turbine Operation
Authors: Davison Craig R. 
Published: July 2013

Repeatable measurement of engine performance requires the system to be near steady state. A technique is presented to assess how close engine operation is to steady state. It estimates the rate of change of the assessed parameter across the sample time and provides an associated confidence interval. This allows a minimum amount of test time to characterize performance and provides consistent criteria to assess steady state.
The technique can either be used online to determine when to take a steady state point or to find the optimal sample from a given data set. To make the technique feasible during testing a recursive method is developed to minimize the computational time.
The technique is demonstrated on known functions with random noise to benchmark its capabilities. This is followed by a demonstration on test data from a small turbo jet engine operated in an altitude facility, a turboprop on an outdoor test stand and an after-burning turbofan in an indoor test cell.
Application of an Optical Pyrometer to Newly Developed Industrial Gas Turbine
Authors: Taniguchi Tomoki , Tanaka Ryozo , Shinoda Yuji , Ryu Masanori , Moritz Norbert , Kusterer Karsten 
Published: July 2013

Kawasaki Heavy Industries, Ltd (KHI) have developed a new industrial gas turbine, L30A. The turbine section composed of two-stage high pressure turbine and three-stage low pressure turbine. In the development period, a commercial pyrometer system was employed to measure blade temperatures under real engine condition. The pyrometer was equipped with an updated detector module and could measure lower temperature compared to the conventional one. Thus it could be used to measure all stages of blades with one pyrometer. The validity of the result was demonstrated by comparing the result with data obtained with other conventional techniques. With the pyrometer system the temperature distribution on the blade surface was easily available and cooling capabilities of blades were evaluated without taking much time.
This paper describes the detail of measurement and evaluation process.
Study of Gas/Liquid Behaviour Within an Aeroengine Bearing Chamber
Authors: Chandra Budi , Simmons Kathy , Pickering Stephen , Collicott Steven H. , Wiedemann Nikolas 
Published: July 2013

Aeroengine bearing chambers typically contain bearings, seals, shafts and static parts. Oil is introduced for lubrication and cooling and this creates a two phase flow environment that may contain droplets, mist, film, ligaments, froth or foam and liquid pools. Some regions of the chamber contain a highly rotating air flow such that there are zones where the flow is gravity dominated and zones where it is rotation dominated.
The University of Nottingham Technology Centre in Gas Turbine Transmission Systems, is conducting an ongoing experimental program investigating liquid and gas flow behavior in a relevant highly rotating environment. Previously reported work by Chandra et al [1, 2] has investigated film thickness and residence volume within a simplified chamber consisting of outer cylindrical chamber, inner rotating shaft and cuboid off-take geometry (termed the generic deep sump).
Recently a more aeroengine relevant bearing chamber offtake geometry has been studied. This geometry is similar to one investigated by Chandra [3] at Purdue University and consists of a “sub-sump” region approached by curved surfaces linked to the bearing chamber.
The test chamber consists of an outer, stationary cylinder with an inner rotating shaft. The rig runs at ambient pressure and the working fluid (water) is introduced either via a film generator on the chamber wall or through holes in the shaft. In addition to visual data (high speed and normal video), liquid residence volume within the chamber and film thickness were the two numerical comparators chosen. Data was obtained for a number of liquid supply rates, scavenge ratios and shaft rotation speeds.
The data from the current model is compared to that from the earlier studies [1, 2, & 3]. The data shows that in contrast to the previously reported generic deep sump study, the residence volume of the curved wall deep sump (CWDS) designs is far less sensitive to shaft speed, liquid supply rate and scavenge ratio. The method of liquid supply only makes a significant difference at the lowest scavenge ratios. Residence volume data for the Nottingham CWDS is comparable, when appropriately scaled, to that for the Purdue design.
The film thickness data shows that at the lower shaft speeds investigated the flow is gravity dominated whereas at higher shaft speeds shear dominates.
Model of a Combined Cycle Steam Section for Use in an On-Line Fuzzy-Based Diagnosis System
Authors: Barbosa Rafael , Ferreira Sandro , Duarte Raphael , Ribeiro Pinto Paula , Paula e Silva Marília 
Published: July 2013

In recent years, combined cycle power plants showed remarkable progress in the safe operation and reliability of their equipment, mostly because of the reliable control and instrumentation systems available today. However, these systems cannot detect and evaluate inconsistencies in the behaviour of equipment due to failures and avoid trips caused by catastrophic events. Computer models developed to simulate the power plant equipment are often employed in diagnosis tools in order to provide accurate healthy parameters that are compared to the field measured parameters.
In this work, the computer models built for the simulation of some of the main bottoming cycle equipment of a real power plant (steam turbine, HRSG, boiler feed water pumps and condenser) are described. These models were developed through characteristics maps and constitutive equations related to the fluid path analysis, implemented in Fortran language.
The results provided by the developed models for each equipment show good agreement with operational data at base and partial load in simulations that covered a good part of the load domain. Due to the good agreement between the measured parameters values and those calculated through simulation, these models are intended to be included in an on-line fuzzy-based diagnosis system.
CFD Modeling of Pulverized Coal Combustion in an Industrial Burner
Authors: Torresi Marco , Fortunato Bernardo , Camporeale Sergio Mario , Saponaro Alessandro 
Published: July 2013

The accurate prediction of pulverized coal combustion in industrial application still remains a great challenge. This is mainly due to the lack of high quality experimental data acquired during the operation of industrial plants.
This work describes the CFD model used in order to numerically simulate the pulverized coal combustion of a full scale, swirl stabilized, aerodynamically staged, industrial burner. In particular, two different combinations of devolatilization and char burnout models were investigated comparing the numerical results with available experimental data obtained during a burner test carried out, in full-scale configuration, in a 50 MWth, fully instrumented, test rig.
In order to avoid any unrealistic assumption on pulverized coal distribution at the burner inlet, the entire primary air duct for pulverized coal transportation has been considered. The main flow is computed solving the steady, incompressible, three-dimensional, Reynolds Averaged Navier-Stokes (RANS) equations, whereas the pulverized coal is simulated as a reacting discrete second phase in a Lagrangian frame of reference, computing the trajectories of the discrete phase entities, as well as heat and mass transfer.
The numerical analysis confirms the very good burner performance obtained during the tests with a very low percentage of fixed carbon left in the ashes.
On Using Fast Response Pressure Sensors in Aerodynamic Probes to Measure Total Temperature and Entropy Generation in Turbomachinery Blade Rows
Authors: Mersinligil Mehmet , Brouckaert Jean-François , Courtiade Nicolas , Ottavy Xavier 
Published: July 2013

This contribution addresses the possibility of exploiting the temperature dependency of piezoresistive sensors as a temperature measurement per se. This requires the characterization of the sensor, or the probe as a temperature probe, i.e. determination of the recovery factor between the sensor temperature and the flow temperature. This temperature calibration as well as the determination of the thermal response time was performed for two probe geometries: a high temperature flush-mounted and a low temperature sub-surface mounted single sensor total pressure probe, both with a probe head diameter of 2.5 mm.
Two applications are reported. The first application was performed with the flush-mounted sensor probe in the high-speed 3 1/2-stage axial compressor CREATE tested in the 2 MW test rig of LMFA at École Centrale de Lyon, in France. The probes were traversed at each inter-row section up to temperatures of 180°C and an absolute pressure of 3 bar. The second application was performed with the sub-surface mounted sensor probe in the high-speed single stage R-4 compressor test rig of the von Karman Institute in Belgium. Both applications have shown results in extremely good agreement with simultaneous total temperature measurements with a Kiel type thermocouple probe. They also underline the necessity of a very accurate temperature calibration.
Finally, considering the fact that a simultaneous temperature measurement can be obtained at the same location as the pressure measurement from the sensor, it is possible to derive entropy generation after a blade row, based on the average pressure and temperature quantities. This unveils another extremely interesting aspect of using the fast response probe technique in turbomachinery applications.
Precision Temperature Detection Using a Phosphorescence Sensor Coating System on a Rolls-Royce Viper Engine
Authors: Feist J. P. , Sollazzo P. Y. , Berthier S. , Charnley B. , Wells J. 
Published: July 2013

By adapting existing thermal barrier coatings a sensor coating has been developed to enhance their functionality, such that they not only protect engine components from the high temperature gas, but can now also measure the material temperature accurately and the health of the coating e.g. ageing, erosion and corrosion. The sensing capability is introduced by embedding optically active materials into the thermal barrier coating and by illuminating these coatings with excitation light phosphorescence can be observed. The phosphorescence carries temperature and structural information about the coating. Knowledge of the exact temperature could enable the design of advanced cooling strategies in the most efficient way using a minimum amount of air. The integration of an on-line temperature detection system would enable the full potential of thermal barrier coatings to be realized due to improved accuracy in temperature measurement and early warning of degradation. This in turn will increase fuel efficiency and reduce CO2 emissions.
Application: The work carried out included the successful implementation of a sensor coating system on a Rolls-Royce Viper engine. The system consists of three components: industrially-manufactured robust coatings, advanced remote detection optics and improved control and readout software. The majority of coatings were based on yttria stabilized zirconia doped with Dy, although other coatings made of yttrium aluminium garnet were manufactured as well. Coatings were produced on a production line using atmospheric plasma spraying. Parallel tests at Didcot power station revealed the durability of specific coatings in excess of 4,500 effective operating hours. It is expected that the capability of these coatings is in the range of normal maintenance schedules of industrial gas turbines of 24,000hrs or even longer. An optical energy transfer system was designed and developed permitting scanning of coated components and also the detection of phosphorescence on rotating turbine blades (13,000 RPM) at probe-to-target distances of up to 400mm. The online measurement system demonstrated precision (around ±5K) comparable to commercial thermocouples and has shown calibration accuracy of ±4K. Transient temperatures were tracked at maximum at 8Hz which is fast enough to follow a typical power generation gas turbine. Repeatable measurements were successfully taken from the nozzle guide vanes (hot), the combustion chamber (noisy) and the rotating turbine blades (moving) and compared with thermocouple and pyrometer installations.
Experimental and CFD Evaluation of the Part Load Performance of a Micro Gas Turbine Fuelled With CH4-N2 Mixtures
Authors: D’Alessandro Bruno , Laranci Paolo , Testarmata Fabio , Fantozzi Francesco 
Published: July 2013

There is a strong interest in numerical and experimental research on syngas combustion in GTs however experimental studies require syngas generation which is costly and also provides a variable and dirty fuel gas. To investigate the combustion behaviour and GT performance when fuelled with low LHV syngas, nitrogen diluted natural gas can be considered.
To this aim the micro gas turbine (mGT) available at the IPRP (Integrated Pyrolysis Regenerated Plant) pilot facility of the University of Perugia, modified to use biomass pyrolysis gas, was fuelled with a CH4−N2 mixtures at different part load conditions obtained from pipeline (CH4) and cylinders (N2). The aim of the work is to analyze the functioning condition of the mGT which is monitored by a dedicated data acquisition system. Performances are evaluated and discussed showing that nitrogen dilution does not affect significantly efficiency and NOx production while CO emission increase slightly when increasing nitrogen content and this is more evident when decreasing the load.
A CFD model of the combustion chamber, which was developed and tuned in previous works by the authors, was also run to reproduce experimental data showing a good agreement and also suggesting flame detachment in the mixing tube when nitrogen is present.
Phosphor Based Temperature Indicating Paints
Authors: Heyes A. L. , Rabhiou A. , Feist J. P. , Kempf A. M. 
Published: July 2013

The ability to measure temperature in extreme environments such as the hot sections of gas turbines is critically important. Several on-line techniques exist but it is often not possible to measure in real-time the temperature of all surfaces of interest. Indeed, some surfaces are so inaccessible as to require complex, costly and intrusive instrumentation for on-line temperature measurement. Here, off-line sensors, also called thermal history sensors, can be used to record the temperatures to which they are exposed, in such a way that they can be extracted later off-line, at room temperature.
Probably the best-known types of thermal history sensor are the colour changing thermal paints, that are widely used in gas turbine development. These have been valuable tools of engine developers for many years, but their use presents a number of challenges so that alternatives would be welcome.
This paper reports the latest developments of a thermal history sensor based on phosphors that undergo permanent changes in their luminescence properties when exposed to high temperatures. Such thermal history sensors have several advantages over and address many of the shortcomings of existing sensors. The paper contains details of the application of a phosphor-based temperature indicating paint based on Y2SiO5:Tb suspended in a chemical binder. The binder was found to influence the optical properties of the phosphor but despite this, a viable sensor paint for temperatures in the range 400°C to 900°C was formed.
A thermal history coating was installed using a thermal barrier coating architecture, applied on various components of a Royce-Rolls Viper 201 engine owned by STS and operated for a number of hours at Cranfield University. Post-operation analysis revealed a temperature distribution on the surfaces/components and enabled hotspots to be identified. Overall the results suggest that phosphor-based temperature indicating paints have the potential to surpass the capability of existing paints.
Accuracy of a sequential approach to identify young febrile infants at low risk for invasive bacterial infection
Authors: Mintegi Santiago , Bressan Silvia , Gomez Borja , Da Dalt Liviana , Blázquez Daniel , Olaciregui Izaskun , de la Torre Mercedes , Palacios Miriam , Berlese Paola , Benito Javier 
Published: July 2013

IntroductionMuch effort has been put in the past years to create and assess accurate tools for the management of febrile infants. However, no optimal strategy has been so far identified. A sequential approach evaluating, first, the appearance of the infant, second, the age and result of the urinanalysis and, finally, the results of the blood biomarkers, including procalcitonin, may better identify low risk febrile infants suitable for outpatient management.ObjectiveTo assess the value of a sequential approach (‘step by step’) to febrile young infants in order to identify patients at a low risk for invasive bacterial infections (IBI) who are suitable for outpatient management and compare it with other previously described strategies such as the Rochester criteria and the Lab-score.MethodsA retrospective comparison of three different approaches (step by step, Lab-score and Rochester criteria) was carried out in 1123 febrile infants less than 3 months of age attended in seven European paediatric emergency departments. IBI was defined as isolation of a bacterial pathogen from the blood or cerebrospinal fluid.ResultsOf the 1123 infants (IBI 48; 4.2%), 488 (43.4%) were classified as low-risk criteria according to the step by step approach (vs 693 (61.7%) with the Lab-score and 458 (40.7%) with the Rochester criteria). The prevalence of IBI in the low-risk criteria patients was 0.2% (95% CI 0% to 0.6%) using the step by step approach; 0.7% (95% CI 0.1% to 1.3%) using the Lab-score; and 1.1% (95% CI 0.1% to 2%) using the Rochester criteria. Using the step by step approach, one patient with IBI was not correctly classified (2.0%, 95% CI 0% to 6.12%) versus five using the Lab-score or Rochester criteria (10.4%, 95% CI 1.76% to 19.04%).ConclusionsA sequential approach to young febrile infants based on clinical and laboratory parameters, including procalcitonin, identifies better patients more suitable for outpatient management.
O-024 A Cost-Effectiveness Analysis of Mechanical Thrombectomy for Acute Ischaemic Stroke in the Stent-Retriever ERA
Authors: Kass-Hout T , Kass-Hout O , Sun C , Gupta R , Nogueira R 
Published: July 2013

Background and purposeEarly Reperfusion is critical for favourable outcomes in ischaemic stroke (AIS). Stent-Retrievers lead to faster and more complete reperfusion than previous technologies. Our aim is to compare the cost-effectiveness of Stent-Retrievers (the Solitaire™ FR device and the Trevo™ Pro Retrieval System) to the previous mechanical thrombectomy devices.MethodsRetrospective review of a prospective collected database of endovascularly treated large vessel AIS in a large academic centre. Data from all consecutive patients who underwent treatment with Merci, Penumbra, intracranial stenting, or Stent-Retrievers from January 2012 through November 2012 were analysed. Baseline characteristics including age, gender, baseline NIHSS, and co-morbidities were analysed. The primary outcomes measures was the total procedural cost (using device list price). Other outcome measures included the rates of successful near-complete or complete recanalisation (TICI 2b-3) and good outcomes (90-day mRS 0–2) as well as the length of stay at the hospital, and the critical care unit. Univariate analysis was performed to identify any differences between the Stent-Retriever (SR) and the Non Stent-Retriever (NSR) groups. Logistic regression analysis was performed to define factors associated with a “high cost procedure” (defined as a cost above the median procedural cost for the overall cohort).ResultsAfter excluding the patients that underwent concomitant extra-cranial stenting (n=22) or received Intra-Arterial t-PA only (n=6), the entire cohort included 150 patients. There were no significant differences in terms of baseline characteristics between the SR group (n= 85) and the NSR group (n=65). The total cost of the reperfusion procedure was significantly higher in the SR group compared to the NSR ($13,419 vs $9,308, p <0.001). We were unable to demonstrate a statistical significant difference in the rates of TICI 2b-3 reperfusion (81 % vs 74% respectively, p= 0.337) or the length of stay (11.1 ± 9.1 days vs 12.8 ± 9.6 days respectively, p=0.260) amongst the SR and the NSR patients./ Notably, the devices procedural cost alone for the SR and NSR treatments comprised 44% and 31% of the national mechanical thrombectomy DRG (MS-DRG 024 = $30,197), respectively.ConclusionThe procedural costs of mechanical thrombectomy for AIS are increasing and account for the bulk of hospitalisation reimbursement. The impact of these expenditures in the long-term sustainability of stroke centres deserves greater consideration. While is likely that the SR technology results in higher rates of optimal reperfusion, better clinical outcomes, and shorter lengths of stay, larger studies are needed to prove its cost-effectiveness.DisclosuresT. Kass-Hout: None. O. Kass-Hout: None. C. Sun: None. R. Gupta: None. R. Nogueira: None.