Development and Application of a Concentration Probe for Mixing Flows Tracking in Turbomachinery Applications

Abstract Modern gas turbines present important temperature distortions in the core-engine flowpath, mainly in the form of hot and cold streaks imputed to combustor burners and components cooling systems. As they highly influence turbines performance and lifetime, the precise knowledge of the thermal field evolution through the combustor and the high-pressure turbine is fundamental. The majority of past studies investigated streaks migrations directly examining the thermal field, while a limited amount of experimental work employed approaches based on the detection of tracer gases. The latter approach provides a more detailed evaluation of the evolution and mixing of the different flows. However, the slow time response due to the employment of sampling probes and gas analysers make the investigation of a whole measurement plane extremely time consuming. To tackle this issue, in this study a commercial oxygen sensor element and its excitation/detection unit were integrated into a newly developed probe to carry out local tracer gas concentration measurements exploiting the fluorescence behaviour. The probe was provided with a Kiel-like shield, a pressure port and a thermocouple, in order to correct the readings in case of 3D flows with pressure, temperature and velocity gradients. The paper summarizes the probe development and calibration activities, with the characterization of its accuracy for different flow conditions. Finally, two probe applications are described: firstly the probe was used to detect tracer gas concentrations on a jet flow; afterwards it was traversed on the interface plane between a non-reactive, lean combustor simulator and the NGV cascade. The probe has proven to provide accurate and reliable measurements both from a quantitative and qualitative point of view even in highly 3D flow fields typical of gas turbines conditions.

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DEVELOPMENT AND APPLICATION OF A CONCENTRATION PROBE FOR MIXING FLOWS TRACKING IN TURBOMACHINERY APPLICATIONS

Journal of Turbomachinery ◽

10.1115/1.4052419 ◽

2021 ◽

pp. 1-35

Author(s):

Giulia Babazzi ◽

Tommaso Bacci ◽

Alessio Picchi ◽

Tommaso Fodelli ◽

Tommaso Lenzi ◽

...

Keyword(s):

Gas Turbines ◽

Thermal Field ◽

Oxygen Sensor ◽

Point Of View ◽

Interface Plane ◽

Tracer Gas ◽

Precise Knowledge ◽

Detailed Evaluation ◽

Detection Unit

Abstract Modern gas turbines present important temperature distortions in the core-engine flowpath, mainly in the form of hot and cold streaks. As they highly influence turbines performance and lifetime, the precise knowledge of the thermal field evolution through the combustor and the high-pressure turbine is fundamental. The majority of past studies investigated streaks migrations directly examining the thermal field, while a limited amount of experimental work employed approaches based on the detection of tracer gases. The latter approach provides a more detailed evaluation of the evolution and mixing of the different flows. However, the slow time response due to the employment of sampling probes and gas analysers make the investigation extremely time consuming. In this study a commercial oxygen sensor element and its excitation/detection unit were integrated into a newly developed probe to carry out local tracer gas concentration measurements exploiting the fluorescence behaviour. The paper summarizes the probe development and calibration activities, with the characterization of its accuracy for different flow conditions. Finally, two probe applications are described: firstly the probe was used to detect tracer gas concentrations on a jet flow; afterwards it was traversed on the interface plane between a non-reactive, lean combustor simulator and the NGV cascade. The probe has proven to provide accurate and reliable measurements both from a quantitative and qualitative point of view even in highly 3D flow fields typical of gas turbines conditions.

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Characterization of Electrolyte Layer for Dissolved Oxygen Sensor

International Journal of Advances in Chemical Engineering and Biological Sciences ◽

10.15242/ijacebs.c1213035 ◽

2014 ◽

Vol 1 (1) ◽

Keyword(s):

Dissolved Oxygen ◽

Oxygen Sensor ◽

Electrolyte Layer

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The Analyses of Learning Strategies in English as a Second Language: Theoretical Classification and Measurement Test

Voices of English Language Education Society ◽

10.29408/veles.v4i2.2199 ◽

2020 ◽

Vol 4 (2) ◽

pp. 118-129

Author(s):

Asti Gumartifa ◽

◽

Indah Windra Dwie Agustiani

Keyword(s):

Language Learning ◽

Learning Outcomes ◽

Learning Strategies ◽

Learning Process ◽

English Learners ◽

English Language ◽

Point Of View ◽

Effective Learning ◽

The Impact

Gaining English language learning effectively has been discussed all years long. Similarly, Learners have various troubles outcomes in the learning process. Creating a joyful and comfortable situation must be considered by learners. Thus, the implementation of effective learning strategies is certainly necessary for English learners. This descriptive study has two purposes: first, to introduce the classification and characterization of learning strategies such as; memory, cognitive, metacognitive, compensation, social, and affective strategies that are used by learners in the classroom and second, it provides some questionnaires item based on Strategy of Inventory for Language Learning (SILL) version 5.0 that can be used to examine the frequency of students’ learning strategies in the learning process. The summary of this study explains and discusses the researchers’ point of view on the impact of learning outcomes by learning strategies used. Finally, utilizing appropriate learning strategies are certainly beneficial for both teachers and learners to achieve the learning target effectively.

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The Algorithm of Characterization of an Action as a Jointly Committed Crime

Rossijskoe Pravo. Obrazovanie, Praktika, Nauka ◽

10.34076/2410-2709-2018-6-37-44 ◽

2018 ◽

pp. 37-44

Keyword(s):

Criminal Code ◽

Point Of View

The article discusses a sequence of activities to identify a crime as jointly committed. The requirements to the algorithm of such activities are formulated. Programme-based and targeted methods applied by the authors allowed detecting a range of stages of the algorithm. The first four stages aim at defining mandatory elements of a crime allowing to characterize it as a jointly committed action. The rest of the stages focus on identifying a type of criminal complicity. In the article, each stage is described. It is emphasized that in each stage there is a special objective. At the same time, all these stages, taken together, constitute a separate module of the program of criminal characterization of an action. From the authors’ point of view, algorithms are necessary not only for detection of crimes and their criminal characterization, but also for answering the question on existence of criminal complicity in each case. Also the authors give their opinions on interpretation of criminal complicity as a legal category. In particular, it is emphasized that not all of crimes merely committed with participation of two or more persons should be understood as jointly committed. It is joint participation that makes a crime jointly committed. Various forms of criminal complicity and types of co-offenders are considered in the article as well. In various crimes, criminal complicity manifests itself differently. Therefore the proposed algorithm can be applied only after identification a specific article of the Russian Criminal Code stipulating the responsibility for the crime committed.

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Micro-Thermal Field-Flow Fractionation

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20021596 ◽

2002 ◽

Vol 67 (11) ◽

pp. 1596-1608 ◽

Cited By ~ 7

Author(s):

Josef Janča

Keyword(s):

High Performance ◽

Thermal Field ◽

Temperature Drop ◽

Point Of View ◽

Constant Field ◽

Field Flow Fractionation ◽

Operational Mode ◽

Experimental Conditions ◽

Standard Size ◽

Flow Fractionation

The effect of miniaturization of the separation channel on the performance of thermal field-flow fractionation (TFFF) is substantiated theoretically. The experiments carried out under carefully chosen experimental conditions proved the high performance of the separation of polymers within an extended range of molar masses from relatively low up to ultrahigh-molar-mass (UHMM) samples. The new micro-TFFF allows to achieve high resolution when applying constant field force operation, it makes easy the programming of the temperature drop which is an advantageous operational mode from the point of view of the time of analysis, and it extends considerably the range of perfectly controlled temperature of the cold wall due to a substantial decrease in the heat energy flux compared with standard size channels.

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Processing Effect and Characterization of Olive Oils from Spanish Wild Olive Trees (Olea europaea var. sylvestris)

Molecules ◽

10.3390/molecules26051304 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1304

Author(s):

Francisco Espínola ◽

Alfonso M. Vidal ◽

Juan M. Espínola ◽

Manuel Moya

Keyword(s):

Phenolic Compounds ◽

Volatile Compounds ◽

Olive Tree ◽

Extraction Yield ◽

Point Of View ◽

Human Consumption ◽

Analytical Point ◽

Wild Olive ◽

Olive Trees

Wild olive trees have important potential, but, to date, the oil from wild olives has not been studied significantly, especially from an analytical point of view. In Spain, the wild olive tree is called “Acebuche” and its fruit “Acebuchina”. The objective of this work is to optimize the olive oil production process from the Acebuchina cultivar and characterize the oil, which could be marketed as healthy and functional food. A Box–Behnken experimental design with five central points was used, along with the Response Surface Methodology to obtain a mathematical experimental model. The oils from the Acebuchina cultivar meet the requirements for human consumption and have a good balance of fatty acids. In addition, the oils are rich in antioxidants and volatile compounds. The highest extraction yield, 12.0 g oil/100 g paste, was obtained at 90.0 min and the highest yield of phenolic compounds, 870.0 mg/kg, was achieved at 40.0 °C, and 90.0 min; but the maximum content of volatile compounds, 26.9 mg/kg, was obtained at 20 °C and 30.0 min. The oil yield is lower than that of commercial cultivars, but the contents of volatile and phenolic compounds is higher.

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Grounding semantic transparency in context

Morphology ◽

10.1007/s11525-021-09382-w ◽

2021 ◽

Author(s):

Rossella Varvara ◽

Gabriella Lapesa ◽

Sebastian Padó

Keyword(s):

Large Scale ◽

Point Of View ◽

Distributional Semantics ◽

Semantic Transparency ◽

Inclusion Measure ◽

The Difference ◽

Semantic Point ◽

The Many ◽

The Relationship

AbstractWe present the results of a large-scale corpus-based comparison of two German event nominalization patterns: deverbal nouns in -ung (e.g., die Evaluierung, ‘the evaluation’) and nominal infinitives (e.g., das Evaluieren, ‘the evaluating’). Among the many available event nominalization patterns for German, we selected these two because they are both highly productive and challenging from the semantic point of view. Both patterns are known to keep a tight relation with the event denoted by the base verb, but with different nuances. Our study targets a better understanding of the differences in their semantic import.The key notion of our comparison is that of semantic transparency, and we propose a usage-based characterization of the relationship between derived nominals and their bases. Using methods from distributional semantics, we bring to bear two concrete measures of transparency which highlight different nuances: the first one, cosine, detects nominalizations which are semantically similar to their bases; the second one, distributional inclusion, detects nominalizations which are used in a subset of the contexts of the base verb. We find that only the inclusion measure helps in characterizing the difference between the two types of nominalizations, in relation with the traditionally considered variable of relative frequency (Hay, 2001). Finally, the distributional analysis allows us to frame our comparison in the broader coordinates of the inflection vs. derivation cline.

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Encephalocele: know it to deal with it

Egyptian Journal of Radiology and Nuclear Medicine ◽

10.1186/s43055-021-00489-y ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Nilkanth Laxman Pal ◽

Ambika Sumeet Juwarkar ◽

Sanjaya Viswamitra

Keyword(s):

Prognostic Factors ◽

Imaging Modality ◽

Point Of View ◽

Extensive Literature ◽

Resonance Imaging ◽

Imaging Protocol ◽

Imaging Protocols ◽

Associated Malformations ◽

Associated Abnormalities

Abstract Background Encephaloceles refer to the herniation of intracranial contents through the defect in the dura and calvarium. This article aims to equip the radiologists with all the necessary information to approach a case of encephalocele in a systematic manner and report in an organized format. Thus reduce the reporting time without overlooking any detail. Main text An extensive literature review was performed searching through the standard textbooks and electronic databases to obtain thorough information on the various encephaloceles particularly from a radiological point of view. The author’s observations were also incorporated in the review. Among the available imaging modalities, magnetic resonance imaging is the most versatile and considered the imaging modality of choice because of superior anatomic resolution in the characterization of central nervous system malformation. This study provides the reporting radiologist with a methodical guide to approach a case of encephalocele discussing the imaging protocol, relevant anatomy, classification, associated abnormalities, and imaging prognostic factors. Conclusion Encephalocele has always been a subject of predicament for radiologists. Understanding the relevant terminologies, anatomy, imaging protocols, classification, associated malformations/anomalies, and imaging prognostic factors will help to methodically approach each case and provide a systematic and comprehensive report.

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Comprehensive Thermodynamic Analysis of the Humphrey Cycle for Gas Turbines with Pressure Gain Combustion

Energies ◽

10.3390/en11123521 ◽

2018 ◽

Vol 11 (12) ◽

pp. 3521 ◽

Cited By ~ 5

Author(s):

Panagiotis Stathopoulos

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Combustion Process ◽

Ideal Gas ◽

Point Of View ◽

Pressure Gain Combustion ◽

Combustion Technology ◽

Secondary Air ◽

And Performance ◽

The Impact

Conventional gas turbines are approaching their efficiency limits and performance gains are becoming increasingly difficult to achieve. Pressure Gain Combustion (PGC) has emerged as a very promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine thermodynamic cycles. Up to date, only very simplified models of open cycle gas turbines with pressure gain combustion have been considered. However, the integration of a fundamentally different combustion technology will be inherently connected with additional losses. Entropy generation in the combustion process, combustor inlet pressure loss (a central issue for pressure gain combustors), and the impact of PGC on the secondary air system (especially blade cooling) are all very important parameters that have been neglected. The current work uses the Humphrey cycle in an attempt to address all these issues in order to provide gas turbine component designers with benchmark efficiency values for individual components of gas turbines with PGC. The analysis concludes with some recommendations for the best strategy to integrate turbine expanders with PGC combustors. This is done from a purely thermodynamic point of view, again with the goal to deliver design benchmark values for a more realistic interpretation of the cycle.

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