bluuebunny/crossref_metadata_2025 huggingface dataset:
Predicting asthma morbidity in children using proposed markers of Th2‐type inflammation
Authors: Konradsen Jon R. , Skantz Elizabeth , Nordlund Björn , Lidegran Marika , James Anna , Ono Junya , Ohta Shoichiro , Izuhara Kenji , Dahlén Sven‐Erik , Alving Kjell , Hedlin Gunilla
Published: August 2015

Background

Assessment of inflammation is becoming a common practice in the clinical work‐up of children with persistent asthma. Biomarkers of Th2‐mediated inflammation include blood eosinophils (B‐Eos), exhaled nitric oxide (FeNO), total serum IgE (S‐IgE), and serum periostin. The aim of this study was to investigate the associations between asthma morbidity and increased levels of these biomarkers in pediatric asthma.

Methods

School‐age children (n = 96) with various manifestations of persistent asthma were included in this nationwide Swedish study. The protocol included the asthma control test, Juniper's quality of life questionnaire (QoL), assessment of pulmonary function, bronchial hyperresponsiveness, height‐adjusted FeNO, blood sampling for S‐IgE, B‐Eos, and periostin, and high‐resolution computed tomography (HRCT) of the lungs.

Results

Children with both high levels of height‐adjusted FeNO and B‐Eos were younger (p = 0.001), had more often severe asthma (p = 0.015), were more allergic (p < 0.001), had a reduced asthma control (p = 0.035), reduced QoL (p = 0.035), more exacerbations (p = 0.004), reduced FEV1/FVC (p = 0.001), and increased bronchial hyperresponsiveness (p < 0.001) as well as greater bronchial wall thickening on HRCT (p = 0.022) compared to those with low levels of both biomarkers. Grouping children according to high and low serum periostin levels did not relate to differences in clinical characteristics and biomarkers.

Conclusions

Assessment of both local and systemic Th2‐mediated inflammation by the analysis of easily attainable biomarkers such as exhaled NO and blood eosinophils has a high predictive value for the identification of children with the highest asthma morbidity. Adjusting FeNO values according to the individual child's height increases the clinical usefulness of this biomarker.
Rupatadine is effective in the treatment of chronic spontaneous urticaria in children aged 2–11 years
Authors: Potter Paul , Mitha Essack , Barkai László , Mezei Györgyi , Santamaría Eva , Izquierdo Iñaki , Maurer Marcus
Published: August 2015

Background

Recommendations in current guidelines for the treatment of chronic spontaneous urticaria (CSU) in infants and children are mostly based on extrapolation of data obtained in adults. This study reports the efficacy and safety of rupatadine, a modern H1 and PAF antagonist recently authorized in Europe for children with allergic rhinitis and CSU.

Methods

A double‐blind, randomized, parallel‐group, multicentre, placebo‐controlled compared study to desloratadine was carried out in children aged 2–11 years with CSU, with or without angio‐oedema. Patients received either rupatadine (1 mg/ml), or desloratadine (0.5 mg/ml) or placebo once daily over 6 weeks. A modified 7‐day cumulative Urticaria Activity Score (UAS7) was employed as the primary end‐point.

Results

The absolute change of UAS7 at 42 days showed statistically significant differences between active treatments vs. placebo (−5.5 ± 7.5 placebo, −11.8 ± 8.7 rupatadine and −10.6 ± 9.6 desloratadine; p < 0.001) and without differences between antihistamines compounds. There was a 55.8% decrease for rupatadine followed by desloratadine (−48.4%) and placebo (−30.3%). Rupatadine but not desloratadine was statistically superior to placebo in reduction of pruritus (−57%). Active treatments also showed a statistically better improvement in children's quality of life compared to placebo. Adverse events were uncommon and non‐serious in both active groups.

Conclusion

Rupatadine is effective and well tolerated in the relief of urticaria symptoms, improving quality of life over 6 weeks in children with CSU. This is the first study using a modified UAS to assess severity and efficacy outcome in CSU in children.
Combination of warming blanket and prewarmed intravenous infusion is effective for rewarming in infants with postoperative hypothermia in China
Authors: Shen Jun , Wang Qin , Zhang YuXia , Wang Xuan , Shi Peng
Published: August 2015

Background

Postoperative hypothermia in the postanesthesia care unit (PACU) in neonates and infants is a well‐known serious complication as it can increase the risk of blood loss, wound infections, and cardiac arrhythmias.

Aim

To identify an effective rewarming method for neonates and infants in China with postoperative hypothermia, an open‐label, randomized, and controlled study was performed to compare the effects of three different rewarming methods.

Methods

Neonates and infants (<1 year) admitted to the PACU after surgery between June 2011 and November 2012 in a local hospital were investigated. Patients diagnosed with hypothermia were randomly divided into three groups and rewarmed with only blanket (blanket group), blanket plus electric blanket (heating blanket group), and blanket plus prewarmed intravenous (i.v.) infusion (warmed infusion group). From the beginning of rewarming, the rectal temperature was recorded every 10 min up to 180 min.

Results

The incidence of postoperative hypothermia in neonates and infants was 5.9%. Patients rewarmed with warming blanket plus prewarmed i.v. infusions showed the shortest rewarming time (67.0 ± 2.6 min, P = 0.02) and highest rewarming efficiency (0.027 ± 0.0008°C·min−1, P = 0.039).

Conclusions

The combination of conventional blanket rewarming and prewarmed i.v. infusion was shown to be an effective rewarming method for hypothermic infants in China.
An Arabidopsis mutant of inositol pentakisphosphate 2‐kinase AtIPK1 displays reduced arsenate tolerance
Authors: Sun Yang‐Yang , Xu Wen‐Zhong , Wu Li , Wang Ruo‐Zhong , He Zhen‐Yan , Ma Mi
Published: August 2015

Arsenate [As(V)] toxicity is considered to be derived from similarities in the chemical properties of As(V) and phosphate (Pi). An Arabidopsis thaliana mutant of inositol pentakisphosphate 2‐kinase (AtIPK1), atipk1‐1, has previously exhibited lower level of phytate and higher level of Pi, relative to wild‐type (WT). Here, atipk1‐1 displayed hypersensitivity to As(V) stress and less As(V) uptake when compared to WT. Overexpression of AtIPK1 controlled by the CaMV 35S promoter partially rescued the As(V)‐sensitive phenotype of atipk1‐1. When compared to control Pi status, addition of Pi enhanced As(V) tolerance of both WT and atipk1‐1 plants, while the arsenic concentration was less reduced in the latter genotype. Despite the higher Pi level in atipk1‐1 than did WT plants, the mutant suffered more severe Pi starvation under Pi limitation stress, indicating that Pi homeostasis was altered in the mutant. Gene expression analysis of WT and atipk1‐1 plants showed the diverse effect of As(V) stress on Pi starvation‐dependent regulation of Pi‐responsive genes. Our study suggested that a particular mechanism of As(V) toxicity existed in atipk1‐1 mutant, and may offer new insights into the interactions between Pi homeostasis and As(V) detoxification in plants.
Politics and Policy in Achieving Participatory Governance in a Developing Country Context
Authors: Waheduzzaman Wahed , As‐Saber Sharif
Published: August 2015

In recent years, “participatory governance” has emerged as an important concept within the governance domain. It is a policy that insinuates participation of local citizens to implement locally based propeople development initiatives. International aid agencies have been pursuing this agenda with an aim to provide greater legitimacy to development projects for economic growth in developing countries. In response, the government of Bangladesh has been trying to implement participatory governance policies for aid‐assisted development projects for the last three decades. However, empirical studies reveal that the level of participation of local citizens in development projects has hardly been improved despite such attempts. Relying on six aid‐assisted project‐based case studies, this article explores the reasons of such a failure and has found out that the dysfunctional political system and corruption in Bangladesh have compromised the role of the state in ensuring any meaningful participation of ordinary citizens in local‐level development activities.

Related Articles

Crowley, Kate. 2009. “.” Politics & Policy 37 (): 995‐1021. http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2009.00208.x/abstract

Mohammed, Abdulai Kuyini. 2013. “” Politics & Policy 41 (): 117‐152. http://onlinelibrary.wiley.com/doi/10.1111/polp.12003/abstract

Stephan, Mark. 2004. “.” Politics & Policy 32 (): 118‐135. http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2004.tb00178.x/abstract

Related Media

Loko, Mico. 2014. A Ladder of Citizen Participation. https://www.youtube.com/watch?v=XLLzd9vDyho

. 2011. Growing Participatory and Deliberative Democracy. https://www.youtube.com/watch?v=dl85BhsYAcQ
Experience of knowledge and skills that are essential in self‐managing a chronic condition – a focus group study among people with type 2 diabetes
Authors: Herre Ann Jorunn , Graue Marit , Kolltveit Beate‐Christin Hope , Gjengedal Eva
Published: August 2015

Aims

The purpose of the study was to gain new knowledge about how people experience participating in diabetes self‐management courses with other people with type 2 diabetes and how they perceive this influences their health and ability to self‐manage the disease.

Methods

We conducted five focus groups with 22 people with type 2 diabetes who had participated in a group‐based diabetes self‐management course. We systematically coded the data and analysed them using Knodel's method.

Findings

Participants gained more nuanced and specific knowledge by participating in a group setting. They increased their theoretical and practical understanding of how to handle diabetes in everyday life. The diabetes self‐management course made the participants more aware of having a disease they had to take more seriously. Learning by being in the situation while guided by professionals was useful. In addition, the participation learned from each other by carrying out real tasks in a context with others struggling with similar treatment demands. They wished more room to perform practical tasks and more independent activity. Further, they suggested to make parts of the course accessible online. Still, it was noted that web‐based solutions cannot replace the practical parts or the dialogue between the participants. They expressed both a need and a wish for a refresher course.

Conclusion

This study underscored that the participants learned through concrete experience, and by trying out practical tasks by becoming part of the diabetes community. They felt safer regarding their own treatment by experiencing a variety of situations in real‐life scenarios.
Teaching note – was the champions league draw rigged?
Authors: Tijms Henk
Published: August 2015

This teaching note gives a real‐life example of Bayesian thinking. It discusses how credible accusations are that the outcome of the draw for the quarter‐finals in the 2013 European Champions League Football was manipulated.
Acid–base balance disturbances in plasma exchange depend on the replacement fluid used
Authors: Cid Joan , Carbassé Gloria , Gamir Montse , Jiménez María , Arellano‐Rodrigo Eduardo , Lozano Miguel
Published: August 2015

BACKGROUND

Metabolic alkalosis occurs as a direct result of plasma exchange (PE) because of metabolism of citrate. However, we observed a decrease of serum pH and bicarbonate after PE when albumin was used as replacement fluid.

STUDY DESIGN AND METHODS

The acid–base balance in 2730 PEs using different replacement fluids (albumin, fresh‐frozen plasma [FFP], or both) was measured, and absolute changes (Δ) in acid–base balance were compared. The frequency of adverse effects (AEs) before and after using prophylactic administration of sodium bicarbonate was compared.

RESULTS

A decrease of serum pH and bicarbonate was observed after PEs when albumin was used as replacement fluid (Δ pH = −0.06 ± 0.04; Δ bicarbonate = −4.03 ± 2.29 mmol/L; Δ base excess = −2.54 ± 3.82 mmol/L). An increase of serum pH and bicarbonate was observed after PEs when FFP was used as replacement fluid (Δ pH = +0.04 ± 0.05; Δ bicarbonate = +3.6 ± 3.68 mmol/L; Δ base excess = +1.62 ± 4.51 mmol/L). The prophylactic administration of sodium bicarbonate corrected partially the decrease of serum pH and bicarbonate after finishing PEs when albumin was used as replacement fluid (Δ pH = −0.04 ± 0.04; Δ bicarbonate = −3.1 ± 2.47 mmol/L; Δ base excess = −3.35 ± 3.06 mmol/L). The frequency of AEs after using prophylactic administration of sodium bicarbonate was lower in comparison with the frequency of AEs before using prophylactic administration of sodium bicarbonate (2.0% vs. 4.8%; p < 0.001).

CONCLUSION

A decrease of serum pH and bicarbonate appeared in patients after PEs when albumin was used as replacement fluid; it was corrected partially with prophylactic administration of sodium bicarbonate, and it was associated with fewer AEs.
Diagnosis of primary secretory otitis media in the cavalierKingCharles spaniel
Authors: Cole Lynette K. , Samii Valerie F. , Wagner Susan O. , Rajala‐Schultz Päivi J.
Published: August 2015

Background

Primary secretory otitis media (PSOM) is a disease reported in the cavalier King Charles spaniel (CKCS). The diagnosis ofPSOMhas been made based only on visualization of a bulging tympanic membrane and mucus in the middle ear post‐myringotomy. No additional tests have been evaluated for the diagnosis ofPSOM;CKCSs with early disease may have been missed.

Hypothesis/Objectives

The objective of this study was to compare otoscopy, tympanometry, pneumotoscopy and tympanic bulla ultrasonography, using computed tomography (CT) as the gold standard for the diagnosis ofPSOMin theCKCS.

Animals

SixtyCKCSs with clinical signs suggestive ofPSOM.

Methods

Otoscopy,CTscan, tympanic bulla ultrasonography, tympanometry and pneumotoscopy were performed; thoseCKCSs with a soft tissue density in the middle ear identified onCThad a myringotomy and middle ear flush.

Results

Forty‐three (72%)CKCSs hadPSOM(30 bilateral, 13 unilateral). A large bulging pars flaccida was identified in only thoseCKCSwithPSOM(specificity of 100%); however, only 21 of 73 ears withPSOMhad a large bulging pars flaccida (sensitivity of 29%). Sensitivity and specificity for tympanometry, pneumotoscopy and tympanic bulla ultrasonography were (84%, 47%), (75%, 79%) and (67%, 47%), respectively.

Conclusions and clinical importance

Based on these results a large bulging pars flaccida indicates the presence ofPSOM, whereas a flat pars flaccida may be present inCKCSthat havePSOMas well as those that do not. InCKCSs with a flat pars flaccida none of the above diagnostic tests can be recommended in place ofCTscan for the diagnosis ofPSOM.
EVOLUTIONARY THEODICY, REDEMPTION, AND TIME
Authors: Robson Mark Ian Thomas
Published: August 2015

Of the many problems which evolutionary theodicy tries to address, the ones of animal suffering and extinction seem especially intractable. In this essay, I show how C. D. Broad's growing block conception of time does much to ameliorate the problems. Additionally, I suggest it leads to another way of understanding the soul. Instead of it being understood as a substance, it is seen as a history—a history which is resurrected in the end times. Correspondingly, redemption, I argue, should not be seen as an event which redeems some future portion of time. God's triumph is over all of history, not just some future temporal portion.
The Role of Wealth Taxes on Property in Poland
Authors: Felis Paweł
Published: August 2015

The article attempts to determine what may be expected from wealth taxes on property in the present Polish economy and in which circumstances. The criteria of assessment are fiscal, economic and social tax functions. The ideas included in the article are meant to contribute to a scholarly discussion on the property taxation order in certain European countries, including Poland. The conclusions from the analysis of functions of wealth taxes on property indicate the necessity for changes in the funding systems of communes in Poland. These taxes have a serious advantage over other sources due to the freedom of disposal and possibility of affecting their volume.
Study on Coupling Optimization Design of Aspirated Compressor Airfoil Based on Two Different Parameterization Methods
Authors: Li Jun , Liu Bo , Yang Xiaodong , Lu Xiaofeng
Published: August 2015

This paper focuses on creating a new design method optimizing both aspirated compressor airfoil and the aspiration scheme simultaneously. The optimization design method is established on the basis of the improved artificial bee colony algorithm. In the process of optimization design, two different parameterization methods (CLSTD and CST method) are used. A high-load aspirated airfoil is designed to demonstrate the complete process and to verify the effectiveness of the new coupling method.

The results show that the total pressure losses of airfoils obtained using CLSTD, CST and Mix method decrease by 23%, 8% and 33% respectively, and the static pressure ratios of the optimized airfoils have a slight improvement. The improved artificial bee colony algorithm indicates a satisfying applicability in aspirated airfoil optimization design, and without affecting the solution precision, the IABC algorithm has a great advantage over standard ABC algorithm in terms of calculation convergence rate. For the high-load aspirated airfoil, the designed leading edge should avoid large spikes in the pressure distribution, and the maximum Mach number in the leading edge needs to be limited. The design that improves the load in the forepart of the aspirated airfoil appropriately, and controls the boundary layer by aspiration is optimum. Although CLSTD method and CST method both perform well, the Mix method which combines CLSTD method with CST method is the optimal in the process of the high-load aspirated airfoil design.
Applicability of Wall-Function Approach in Simulations of Turbomachines
Authors: Juckelandt Kay , Wurm Frank-Hendrik
Published: August 2015

Numerical simulations of centrifugal pumps with low specific speed show significant differences in calculated efficiency from experiments. This causes designers to refrain from CFD methods and stick to prototyping. Investigations regarding the applicability of numerical simulations on these pumps are carried out. Unsteady simulations of a low specific speed pump are performed. The focus of this paper is boundary layer treatment, as losses due to boundary layer flow are dominant in low specific speed pumps. The wall-function as well as the low-Reynolds-number method is applied for boundary layer treatment. A method to calculate the local modeling error of the wall-function method is introduced. Experiments on a test pump are conducted to validate the simulations. Performance curves, locally highly resolved pressure distributions and velocity profiles are obtained. Simulations with resolved boundary layers match experimental data very good. It is shown that simulated efficiency is sensitive to the boundary layer treatment. The wall-function simulations deviate significantly at off-design flow rate, particularly at overload. The analysis reveals that modeling errors of the wall-function method mainly contribute to incorrect loss prediction. A local modeling error distribution is calculated and a meshing guideline for low specific speed pumps is derived.
Performance Influences of Hydrogen Enriched Fuel on Heavy-Duty Gas Turbines in Combined Cycle Power Plants
Authors: Seydel Carl Georg
Published: August 2015

In order to meet the ambitious reduction targets for future CO2 emissions and fossil fuel consumption, the extension of renewable power systems is mandatory. One main issue is the fluctuating and unpredictable availability of renewable energy. With a higher portion of renewable energy, a secure electricity supply becomes more challenging. On days with high electricity demand but low availability of renewable energy, fossil back up power plants with high flexibility and efficiency are needed. Most applicable for this requirements are combined cycle power plants, which provide both high flexibility and efficiency. On the other hand potential renewable energy is wasted during days with low electricity demand but high available renewable energy, because electricity cannot be stored yet economically in such vast amounts. In order to use the available renewable energy more efficiently, hydrogen could be produced via electrolysis during phases of surplus available renewable energy. The hydrogen serves as a high density energy storage, which can be used as an alternative fuel in combined cycle power plants for a highly efficient reconversion into electricity if necessary.

In this study it is analyzed how the usage of hydrogen as the burner fuel will influence the performance of combined cycle power plants. Therefore the on- and off-design performance of a state of the art combined cycle power plant will be calculated at different ratios of hydrogen mixtures with natural gas. The thermodynamic calculations are made with the performance software GTlab of the German Aerospace Center. Furthermore the natural gas and CO2 savings for different hydrogen ratios will be quantified.

The results show that the usage of hydrogen enriched fuel increases the combined cycle efficiency and power output. Accordingly a considerable reduction in CO2 emissions and fossil fuel consumption is possible.
Adaptive Control of Mixture Profiles for a Combustion Tube
Authors: Schäpel Jan-Simon , King Rudibert , Bobusch Bernhard , Moeck Jonas , Paschereit Christian Oliver
Published: August 2015

Due to the increased thermodynamical efficiency of a constant-volume combustion compared to a constant-pressure mode, the former one represents an attractive alternative for future gas turbines. The shockless explosion combustion is a method to create a detonation without pressure peaks due to a simultaneous autoignition of the fuel. This method leads to high requirements regarding the filling process. Considering disturbances in the detonation tube these requirements can only be met using closed-loop control. In this paper two adaptive control algorithms are tested on a non-reactive surrogate set-up. One of these control schemes is a novel formulation of a discrete extremum seeking controller. By estimating the first derivative and Hessian matrix of the system, this controller is able to use steps of the Newton method to converge to the optimal control trajectory. This controller is compared to an iterative learning controller using a black-box model with a Hammerstein compensation.
Different Flame Patterns Linked With Swirling Injector Interactions in an Annular Combustor
Authors: Durox Daniel , Prieur Kevin , Schuller Thierry , Candel Sébastien
Published: August 2015

It is known from cold flow experiments that linear arrays of injectors may feature different types of aerodynamic patterns (see for example ASME-GT2013-94280, ASME-GT2014-25094). There are however no indications on what can happen under hot fire conditions since most experiments have been carried out in the absence of reaction or in single injector configurations. It is now possible to investigate this issue by making use of a recently developed annular combustion chamber. This device designated as MICCA is equipped with multiple swirling injectors and its side walls are made of quartz providing full optical access to the flame region thus allowing detailed studies of the combustion region structure and dynamics. Experiments reported in this article rely on direct observations of the flame region through light emission imaging using two standard cameras and an intensified high speed CMOS camera. The data gathered indicate that interactions between successive injectors give rise to patterns of flames which exhibit an alternate geometry where one flame has a relatively low expansion angle while the next spreads sideways. This pattern is then repeated with a period which corresponds to twice the injector spacing. Such arrangements arise when the angle of the cup used as the end-piece of each injector exceeds a critical value. Effects of mass flow rate, equivalence ratio, and injector offset are also investigated. It is shown that the angle which defines the cup opening is the main control parameter. It is also found that when this angle exceeds a certain value and when the laminar burning velocity is fast enough, the flame pattern switches in an unsteady manner between two possible configurations. This unsteady behavior is characterized using high-speed imaging. It is finally shown that these alternating flame patterns lead to alternating heat release rate distributions and inhomogeneous heat transfer to the chamber walls featuring a helicoidal pattern.
Influence of Geometrical Parameters on Aerodynamic Optimization of a Mixed-Flow Turbocharger Turbine
Authors: Khairuddin Uswah , Costall Aaron W. , Martinez-Botas Ricardo F.
Published: August 2015

This paper describes an optimization procedure to modify the geometry of a mixed-flow turbocharger turbine for improved aerodynamic efficiency. The procedure integrates parameterization of the turbine blade geometry, genetic algorithm optimization, and 3D CFD analysis using a commercial solver.

Using a known mixed-flow turbocharger turbine as the baseline, the main features of the blade geometry — the hub, shroud, camberline, leading and trailing edge profiles — were separately adjusted by the genetic algorithm in the direction of better efficiency. Apart from optimizing the subject turbine for the operating point in question, more usefully this permits each geometrical feature to be ranked by their contribution to the change in efficiency. Cases were also run in which the hub and shroud curves were simultaneously adjusted. Analysis of CFD results provides additional insight into the underlying reasons for efficiency changes by examination of the relevant flow field features.

The hub and shroud profiles were observed to have the greatest impact on turbine performance, optimization of which leads to an increase of 1.3 percentage points of efficiency. This compares to only 0.2 percentage points improvement following optimization of the outlet geometry.
Soot Reduction in Gas Turbine Combustors Using Oxidation Catalyst Additives
Authors: Marikkar Nuhuman , Vierling Matthieu , Aboujaib Maher , Denolle Richard , Moliere Michel
Published: August 2015

The combustion of viscous ash forming fuels generates soot and ash that collectively form the so called particulate matter (PM). In addition to existing SOx and NOx emission regulations, the World Bank has enacted a 50 mg/Nm3 limit for the PM emissions of large combustion plants, creating a new challenge to power generators who use heavy fuel oils. LTL Holdings Ltd (Colombo, Sri Lanka) that own and operate a 300MW heavy-fueled gas turbine combined cycle (GTCC) at its Kerawalapitiya (Sri Lanka) power plant and GE Power & Water have embarked on a study intended to investigate the best PM abatement technique for heavy fueled gas turbines. This was done with TEKAT Ltd (London, UK) as the additive suppliers and the IRTES-LERMPS laboratory (Sévenans, France). In recent lab and field tests, the authors have thus evaluated the soot abatement capability of various combustion catalysts at different dosages. The results show that cerium proves an efficient oxidation catalyst in a real gas turbine, irrespective to its chemical form (Ce(III) or Ce(IV)), providing very substantial soot abatement rates. After briefly reviewing the different PM abatement techniques, the paper focuses on the lab and field tests performed and places emphasis on the performances of cerium in gas turbine combustors, along with the complex ash chemistry developed by heavy fuel oils.
Operational Issues With Gas Turbines Intake Air Filters in Watson Cogeneration Facility
Authors: Ingistov Steve
Published: August 2015

Intake air filtration is crucial in performance and reliability of combustion gas turbine situated in typical industrial environment such as large petrochemical plant, refinery and industrial plant.

The air-born pollutants vary in size and composition and their arrestance is of fundamental value to the life expectancy of the turbine rotating and stationary elements. In addition, the air-born pollutants which pass the intake air filter elements tend to foul the axial compressor blades both stationary and rotating. The result of the particular fouling is the creation of an additional, parasitic load on the gas turbine, driver. A as result the heat rate of a gas turbine will increase and also the production of CO2 will increase too.

Watson Cogeneration Plant is located in a typical industrial environment, very close to the major freeway and to the Pacific Coast. This paper describes field experience accumulated during the last three years of continuous operation under the base load of one of the four gas turbines, GT Unit 92, furnished with advanced, HEPA Class 12 intake air filters. Intake air filters durability which plays more and more decisive role in gas turbine successful operation and maintenance is also discussed.
Validation of a T100 Micro Gas Turbine Steady-State Simulation Tool
Authors: Henke Martin , Klempp Nikolai , Hohloch Martina , Monz Thomas , Aigner Manfred
Published: August 2015

Micro gas turbines (MGT) provide a highly efficient, low-pollutant way to generate power and heat on-site. MGTs have also proven to be a versatile technology platform for recent developments like utilization of fuels with low specific heating values and solar thermal electricity generation. Moreover, they are the foundation to build novel cycles like the inverted Brayton cycle or fuel cell hybrid power plants.

Numerical simulations of steady operation points are beneficial in various phases of MGT cycle development. They are used to determine and analyze the future potentials of innovative cycles for example by predicting the electrical efficiency and they support the thermodynamic design process (by providing mass flow, pressure and temperature data). Numerical Simulation allows to approximate off-design performance of known cycles e.g. power output at different ambient conditions. Additionally, numerical simulation is used to support cycle optimization efforts by analyzing the sensitivity of component performance on cycle performance. Numerical models of the MGT components have to be tuned and validated based on experimental data from MGT test rigs.

At DLR institute of combustion technology a MGT steady-state cycle simulation tool has been used to analyze a variety of cycles and has been revised for several years. In this paper, the validation process is discussed in detail. Comparing simulation data with measurement data from the DLR Turbec T100 test rig has led to extensions of the numeric models, on the one hand, and to modifications of the test rig on the other. Newly implemented numerical models account for the generator heat release to the inlet air and the power electronic limitations. The test rig was modified to improve the temperature measurement at positions with uneven spatial temperature distribution such as the turbine outlet. Analyzing these temperature distributions also yields a possible explanation for the apparent strong recuperator efficiency drop at high load levels, which was also observed by other T100 users before.
Conjugate Heat Transfer Optimization of the Nonuniform Impingement Cooling Structure of a HPT 2nd Stage Vane
Authors: Chi Zhongran , Liu Haiqing , Zang Shusheng , Jiao Guangyun
Published: August 2015

This paper discusses the methodology of impingement cooling optimization of a gas turbine 2nd stage vane with 3D conjugate heat transfer (CHT) CFD analysis applied. The vane is installed with a novel impingement cooling structure in the leading cavity and a pin-fin array in the trailing edge. This study involves the optimization of the impingement cooling structure, including the location of the jet holes and the diameter of each hole. The generation of 3D model and CHT mesh was realized using an in-house code developed specifically for turbine cooling optimization. A constant pressure drop was assumed within the cooling system during optimization. To make the optimization computationally faster, a metamodel which can predict the detailed distribution of metal temperature on the vane surface was used in the second-level search together with a genetic algorithm. An optimal nonuniform impingement cooling structure in the leading cavity was automatically designed by the optimization process costing only dozens of CFD runs, which provided a more uniform temperature distribution on the vane surface and required no more coolant amount compared with the initial impingement cooling structure.
Towards Unsteady Simulation of Combustor-Turbine Interaction Using an Integrated Approach
Authors: Raynaud Félix , Eggels Ruud L. G. M. , Staufer Max , Sadiki Amsini , Janicka Johannes
Published: August 2015

In this paper a CFD solver with the ability of dealing with both reacting and compressible flows is developed, so that an integrated simulation of the whole system “combustor and turbine” can be performed. To its validation, the combustor-turbine interaction in a jet engine consisting of a Rolls-Royce combustor together with the first high-pressure turbine stage NGV (Nozzle-Guide-Vane) is studied. The unstructured CFD solver follows a pressure-based approach, using a PISO algorithm (Pressure Implicit with Splitting of Operator) recently extended for compressible flows. In order to allow acoustic waves to leave the computational domain, nonreflecting boundary conditions based on the NSCBC method (Navier-Stokes Characteristic Boundary Conditions) have been implemented. The numerical methods have been coupled with the Flamelet Generated Manifold combustion model (FGM) extended for compressible flows.

After successfully verifying the NSCBC implementation, various numerical results describing the combustor-turbine interactions of the jet engine are analyzed and discussed in terms of temperature and total pressure fields with and without NGV. It could be shown that the influence of the NGV on the combustor flow is relatively limited. Differences in the combustor flow field are mainly due to spatial and temporal averaging used for the simulation without NGV to calculate the pressure field at combustor outlet.

These numerical results demonstrate the ability of the developed numerical model in its steady computation mode to well capture the evolving flow properties in both combustor and turbine components.
Fully Coupled Through-Flow Method for Industrial Gas Turbine Analysis
Authors: Petrovic Milan V. , Wiedermann Alexander
Published: August 2015

A fully coupled method for calculation of the entire flow in single- and twin-shaft industrial gas turbines is described. It is based on individual through-flow methods for axial compressors and air-cooled gas turbines developed by the authors that are coupled using simple combustion and cooling flow models connecting compressor and turbine flow paths. The through-flow computation for the analysis of cooled axial multistage turbines is fed by air from the compressor bleeds, which are part of the through-flow model of the compressor. The through-flow methods are based on a stream function approach and a finite element solution procedure. They include high-fidelity loss and deviation models with improved correlations. Advanced radial mixing and endwall boundary layer models are applied to simulate 3D flow effects. For air-cooled turbine analysis, various types of cooling air injection were adopted: film cooling, trailing edge injection and disc/endwall coolant flow. Compressor and turbine flow path computations were extensively validated individually and previously published by the authors.

The coupled method was applied to operation analysis and performance prediction of a newly developed industrial gas turbine in single- and twin-shaft configurations. In the latter case, the matching point of the compressor and high-pressure turbine has to be determined iteratively as a function of the compressor speed line, firing temperature, cooling and bleed-off characteristics, which may be important for strong part-load behavior. This process is explained in the paper.

Predicted gas turbine operation points are compared with experimental test data. It is demonstrated that the new method presented is an essential tool for overall gas turbine design and matching of the gas turbine components based on test rig experience. In addition, it is useful for diagnosis and supports the root-cause analysis of misbehaving field engines.
Numerical Simulation of the Flow Field in a High Speed Multistage Compressor: Study of the Time Discretization Sensitivity
Authors: Schreiber Johannes , Ottavy Xavier , Ngo Boum Ghislaine , Aubert Stéphane , Sicot Frédéric
Published: August 2015

The following numerical investigations are performed in the frame of a research project that aims at a better understanding of the flow unsteadiness that develops in a multistage high-speed axial compressor. First, the paper presents a new version of the 3.5 stages high-speed axial compressor CREATE (Compresseur de Recherche pour l’Etude des effets Aérodynamiques et TEchnologiques), which has been designed by Snecma and is based at the LMFA (Laboratory for Fluid Mechanics and Acoustics) on a 2MW test rig. This paper is based on numerical results obtained with 3D steady and unsteady RANS computations using the CREATE configuration. The unsteady RANS simulations are carried out over the whole spatial and temporal periodicity of the compressor. The main numerical setup has been fixed according to the state of the art. Second, the effect of three different time discretizations on the flow field in CREATE is discussed. The global performance of the compressor is not significantly affected. However the change in the time discretization impacts the structure of the flow at specific locations. The main focus of this study lies on the transport of flow structures and the analysis of their interactions. A double modal decomposition method, which highlights the specific contribution of the interactions on the overall flow field, is applied for the study of the highly complex and unsteady flow field. It allows identifying which interactions are more sensitive to the change in the time discretization.
About Transonic Compressor Tandem Design: A Principle Study
Authors: Hergt A. , Siller U.
Published: August 2015

The development of modern axial compressors has already reached a high level. Therefore an enlargement of the design space by means of new or advanced aerodynamic methods is necessary in order to achieve further enhancements of performance and efficiency. The tandem arrangement of profiles in a transonic compressor blade row is such a method. For an efficient industrial application the knowledge of the fundamental design principles is needed. This paper presents the recent research work on transonic compressor tandem profiles at DLR Institute of Propulsion Technology. It deals with the fundamental description of the operation principles of a modern transonic compressor tandem cascade. By considering these principles and based on an optimization database with over 1200 members design recommendations are developed.
LES and Hybrid RANS/LES Simulations of Turbomachinery Flows Using High Order Methods
Authors: Marty Julien , Lantos Nicolas , Michel Bertrand , Bonneau Virginie
Published: August 2015

The flow within turbomachinery applications is intrinsically complex and unsteady, and involves boundary layer transition, separation and vortices such as tip leakage vortex and wakes. Recent investigations show that Large Eddy Simulation and hybrid RANS/LES methods are required to accurately capture such flows. It is well-known that the numerical dissipation coming from the spatial discretization scheme must not be excessive because it can have a significant influence on the results. The present investigation assesses the impact of upwind spatial discretization scheme AUSM+(P) with high-order MUSCL extension at third- and fifth-order applied to different turbomachinery cases: (i) Large Eddy Simulation (LES) of laminar separation bubble over the high-lift low-pressure turbine airfoil T106C. The present investigation shows that the MUSCL extension to high-order is compatible with no-match boundaries and solution accuracy is not impacted. (ii) Zonal Detached Eddy Simulation (ZDES) of the first rotor of the transonic research compressor CREATE. Since a shock is present near the blade tip, a mixed scheme is developed in order to improve the robustness of the high-order scheme. The spectral analysis shows that the high-order scheme improves the resolution of small vortical structures. (iii) Zonal Detached Eddy Simulation of a fan rotor in order to well predict the broadband noise due the interaction between the fan wake and the OGV. Third and fifth order schemes are compared for both aerodynamic and acoustic purposes. The wake is well captured by the ZDES method and the velocity power spectral density is well predicted with this advanced method.
Development and Application of Low Pressure Stages for Large Flow and High Speed Unit
Authors: Xin Xiaopeng , Sui Yongfeng , Mao Hanzhong , Chu Peng , Kong Jianqiang , Ye Zhong
Published: August 2015

New low pressure stages with twisted long blades were developed for 1000MW boiler feed water pump turbine (BFPT) of full capacity. The development process includes both CFD design and CAE design. Compared with half capacity, full capacity BFPT is now facing great market requirements. The difficulty lies in large flow of 100t/h and high speed of 5200rpm, which demands good strength and aerodynamic performance. The static stress and dynamic stress should be checked comprehensively. Air bending stresses of the twisted blades were calculated by three different methods. The fluid-solid coupling method for predicting air bending stress is better than traditional method, which can especially predict the effect of the blade root fillet and lacing convex on strength. The aerodynamic performance of the low pressure stages was given by variable condition calculation. Further improvements in efficiency were obtained by flow and structure optimization. This article describes the features and the development process of BFPT low pressure stages.
Gas Turbine Exhaust Temperature Measurement Approach Using Time-Frequency Controlled Sources
Authors: DeSilva Upul , Bunce Richard H. , Schmitt Joshua M. , Claussen Heiko
Published: August 2015

Siemens has developed a novel approach for measuring the process gas temperature leaving the power turbine in their heavy industrial gas turbine engines using active acoustic tomography. Siemens has deployed this measurement technique on two test engines of different power ranges and different combustion and exhaust duct configurations. These engine tests have demonstrated that this technology is effective and robust. All working parts are outside the heat effective zone so, unlike the traditional intrusive point temperature measurement method, sensors are easily replaceable during engine operation.

Bulk exhaust temperature is used in performance testing of industrial gas turbine engines and is a critical measurement for power production. Temperature distribution information in the exhaust plane is valuable for safe engine operation and can be used to prevent lifetime reduction due to hotspots or to monitor the burner flames.

Siemens used broadband sound sources for the previously reported acoustic pyrometer experiments. This paper extends this work utilizing sparse time-frequency encoded sources to improve the robustness of time of flight estimation in the high noise area of the turbine exhaust. The goal is to achieve a higher signal to noise ratio between the emitted and received signals by focusing the acoustic energy into narrow time-frequency bins that are little affected by turbine noise. Different acoustic patterns are tested and compared to the previously used broadband source both in laboratory experiments and a turbine test bed. The patterns are evaluated regarding their noise robustness, sound pressure levels and narrow autocorrelation which are important for accurate time of flight estimation in high noise environments.
A Three-Dimensional Analysis Code of Compressor Performance and Stability for Steady Inlet Distortion
Authors: Guo Jin , Hu Jun , Yin Chao
Published: August 2015

Inlet distortion has a great impact on the compressor performance and stability. Developing a model which quickly and accurately can assess the performance and stability of a compressor with inlet distortion is one of the key technologies needed to improve the fidelity of a compressor design system. Thus, a new 3-D analysis code called CSAC based on the theory of body force model has been developed and used to predict compressor performance and stability with inlet distortion. The code solves the compressible 3-D Euler equations modified to include source terms which represent the effect of the blade rows. The source terms were calculated by the velocity circulation vectors and entropy production which were extracted from the 3-D Navier-Stokes (N-S) steady-state solutions at the stations between each blade row at many operating points with clean inflow. An analysis was carried out to determine the local flow conditions for parameterizing the magnitude of the velocity circulation vectors and entropy production of individual blade rows.

A NASA stage 35 flow field with clean inlet was simulated with the code. The calculation results agreed well with the N-S solutions and experimental data. The stage 35 performance and stability with inlet steady circumferential total pressure distortion was also simulated using the code. The predicted performance maps of the stage 35 with inlet distortion showed a reduced range and pressure rise. In addition, the results reflected the strong three-dimensional characteristics of the flow field with inlet distortion, and the interaction of the blade rows with the upstream flow field. This paper describes the modeling method of CSAC and presents a detailed examination of the computed results.
An Approach for Estimating the Effect of Transient Sweep Through a Resonance
Authors: Hackenberg Hans-Peter , Hartung Andreas
Published: August 2015

The difference of a stationary forced response situation of a turbine or compressor blade relative to a transient resonance sweep is well known and documented in the literature. Different approaches have been used to understand the effect on transient amplitude in comparison with forced response. The dependencies on damping levels and resonance passage speed have been noted. Estimates for a critical or/and maximum sweep velocity have been given.

The understanding of transient response during resonance sweep is of practical importance for instance when running a certification stress test for an aircraft engine, where it needs to be decided upfront which acceleration rate (increase in rpm per second) to use to ensure that the maximum airfoil response that could be attained under stationary condition is being measured with sufficient precision. A second reason for understanding of transient response is the verification of correct, if relevant lower, component life usage during transient regimes in operation.

This paper gives a proposal for a simple 1D method based on one degree of freedom (1-dof) system considerations for estimating the transient response dependency on the sweep velocity, damping levels and resonance frequency. The method is verified with 3D analyses of more complex blade-disc structures, which have been validated with air jet excitation rig and aero engine tests. Using the results of the 1-dof analysis, an estimate of the expected stationary resonance response increase can be formulated even in cases where the measured data are based on a significant deviation from the desired sweep velocity, where transient effects would be significant.