The Effects of a Parametric Variation of the Rim Seal Geometry on the Interaction Between Hub Leakage and Mainstream Flows in HP Turbines

2012 ◽  
Author(s):  
I. Popović ◽  
H. P. Hodson
Keyword(s):  
Large Scale ◽  
Full Range ◽  
The Other ◽  
Flow Uniformity ◽  
Flow Rates ◽  
Linear Cascade ◽  
Parametric Variation ◽  
Optimum Geometry ◽  
Parametric Studies ◽  
Mass Flow Rates

The objective of this work was to assess and understand the effects of parametric variation performed on a typical overlapping rim seal geometry. The datum geometry has been focus of a detailed experimental investigation employing a large-scale linear cascade subjected to a range of the mass flow rates and swirl velocities of the leakage air. The parametric variations described in this paper were examined using validated CFD. As a part of the parametric studies, both the axial and the radial seal clearance between the rotor fin (angel wing) and stator platform were varied as well as the length of the overlap between stator and rotor platforms. In addition, the effects of forward and backward facing annulus steps were also investigated. It has been found that a backward facing annulus step was detrimental for all conditions considered, while a forward facing step offered improvements for smaller step heights and/or lower leakage fractions. Tightening of the seal clearances closer to the annulus line improved the sealing effectiveness, but often at the expense of increased losses. On the other hand, increasing the overlap length led to improvements in the sealing effectiveness with very small effects on the overall losses. Moving the rim seal away from the blade leading edges reduced the pressure asymmetry at the rim seal and increased the flow uniformity of the leakage air. However, this led to an increased cross-passage flow (more negative skew) and higher losses at all but lowest leakage fractions. The results presented in this paper highlight the fact that there may not be an optimum rim seal solution that would offer an improvement for the full range of leakage fractions and that for different rim sealing flows there may be a different optimum geometry. In addition, rotor disc movements in radial and axial directions at various off-design conditions should be considered as a part of the design process. Based on the presented results it may be of a benefit to the turbine designer to consider rotor disc designs which would be more biased towards the upstream and outward disc movements that would result in tightening of the seal clearances and avoidance of a backward facing annulus step.

The Effects of a Parametric Variation of the Rim Seal Geometry on the Interaction Between Hub Leakage and Mainstream Flows in High Pressure Turbines

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Ivan Popović ◽  
Howard P. Hodson
Keyword(s):  
Large Scale ◽  
Full Range ◽  
Flow Uniformity ◽  
Linear Cascade ◽  
Parametric Variation ◽  
Optimum Geometry ◽  
Parametric Studies ◽  
Mass Flow Rates ◽  
Rotor Disk ◽  
Computational Fluid Dynamics Cfd

The objective of this work was to assess and understand the effects of a parametric variation performed on a typical overlapping rim seal geometry. The datum geometry has been the focus of a detailed experimental investigation employing a large-scale linear cascade subjected to a range of the mass flow rates and swirl velocities of the leakage air. The parametric variations described in this paper were examined using validated computational fluid dynamics (CFD). As a part of the parametric studies, both the axial and the radial seal clearance between the rotor fin (angel wing) and stator platform were varied as well as the length of the overlap between stator and rotor platforms. In addition, the effects of forward and backward facing annulus steps were also investigated. It has been found that a backward-facing annulus step was detrimental for all conditions considered, while a forward-facing step offered improvements for smaller step heights and/or lower leakage fractions. Tightening of the seal clearances closer to the annulus line improved the sealing effectiveness but often at the expense of increased losses. On the other hand, increasing the overlap length led to improvements in the sealing effectiveness with very small effects on the overall losses. Moving the rim seal away from the blade-leading edges reduced the pressure asymmetry at the rim seal and increased the flow uniformity of the leakage air. However, this led to an increased cross-passage flow (more negative skew) and higher losses at all but lowest leakage fractions. The results presented in this paper highlight the fact that there may not be an optimum rim seal solution that would offer an improvement for the full range of leakage fractions and that, for different rim sealing flows, there may be a different optimum geometry. In addition, rotor disk movements in radial and axial directions at various off-design conditions should be considered as a part of the design process. Based on the presented results, it may be of a benefit to the turbine designer to consider rotor disk designs that would be more biased towards the upstream and outward disk movements, which would result in tightening of the seal clearances and avoidance of a backward-facing annulus step.

scholarly journals Simulation Analysis of Solution Transportation Absorption Chiller with the Capacity from 25 RT to 1000 RT

2017 ◽  
Author(s):  
Koji Enoki ◽  
Fumi Watanabe ◽  
Seigo Tanaka ◽  
Atsushi Akiwawa ◽  
Toshitaka Takei
Keyword(s):  
Mass Flow ◽  
Large Scale ◽  
Working Fluid ◽  
Cooling Power ◽  
Absorption Chiller ◽  
Long Distance ◽  
Flow Rates ◽  
Heat Demand ◽  
Mass Flow Rates ◽  
Wasted Heat

Utilization of wasted heat instead of fuel combustion is effective to reduce primary energy consumption for mitigating global warming problem. Because wasted heat sources are not necessarily located close to areas of heat demand, one of the difficulties is that wasted heat has to be transferred from heat source side to heat demand side, which may require heat transportation over long distance. From this point we proposed and have examined new idea of heat transportation using ammonia-water as the working fluid which system is named Solution Transportation Absorption chiller, in short STA. Our previous studies of STA were mainly the experimental investigation with STA facility which cooling power was 25RT (90kW). As a result, the COP of STA was found almost same value 0.65 with the conventional absorption chiller without depending on the transportation distances. The simulation using AspenHYSYS also examined with same experimental condition. The experimental data showed good agreement with the simulation calculation. In this study, we examined the large-scale cooling power STA on simulation. The examination cooling powers were from 90 kW(25RT) to 3517 kW(1000RT). All cooling power achieved around COP 0.64 including pump power consumptions. In addition, we performed the dynamic simulation. As the results, there was no effect of pipeline size on the cooling capacities and mass flow rates. Furthermore, the stability time of the cooling capacities and mass flow rates were almost same regardless of the pipeline size and cooling capacity. In other words, STA may be achieved the same COP even though having various complex conditions compared with the conventional absorption chiller.

Birlikte Yaşama Kültürü Çerçevesinde Avrupa Birliği ve Türkiye Politikaları: Suriyelilere Yönelik Tutumun Sultanbeyli Örneği Üzerinden Değerlendirilmesi

2017 ◽  
Vol 4 (1) ◽  
pp. 41-61
Author(s):  
Pelin Sönmez ◽  
Abulfaz Süleymanov
Keyword(s):  
Civil Wars ◽  
Large Scale ◽  
Social Acceptance ◽  
Point Of View ◽  
The Other ◽  
Syrian Refugees ◽  
The European Union ◽  
International Protection ◽  
Legal Structure ◽  
Turkish People

Türkiye, Cumhuriyet tarihinin en yoğun zorunlu göç dalgasını 2011 yılından bu yana süren Suriye Savaşı ile yaşamaktadır. Suriye vatandaşlarının geçici koruma statüsü altında Türkiye toplumuna her açıdan entegrasyonları günümüzün ve geleceğin politika öncelikleri arasında düşünülmelidir. Öte yandan ülkeye kabul edilen sığınmacıların kendi kültürel kimliğini kaybetmeden içinde yaşadığı ev sahibi topluma uyumu, ortak yaşam kültürünün gelişmesi açısından önem arz etmektedir. Bu makalede, "misafir" olarak kabul edilen Suriyeli vatandaşların Türk toplumunca kabul edilmeleri ve dışlanma risklerinin azaltılmasına yönelik devlet politikaları ortaya konularak, üye ve aday ülkelere göçmenlerin dışlanmasını önlemek için Avrupa Birliği (AB) tarafından sunulan hukuki yapı ve kamu hizmeti inisiyatifleri incelenmekte, birlikte yaşam kültürü çerçevesinde Suriyeli vatandaşlara yönelik  toplumsal kabul düzeyleri ele alınmaktadır. Çalışma iki ana bölümden oluşmaktadır: göçmen ve sığınmacılara karşı toplumsal dışlanmayı engellemek için benimsenen yasa ve uygulamaların etkisi ve İstanbul-Sultanbeyli bölgesinde Suriyeli sığınmacılarla ilgili toplumsal algı çalışmasının sonuçları. Bölgede ikamet eden Suriyelilere yönelik toplumsal kabul düzeyinin yüksek olduğu görülürken, halkın Suriyelileri kendilerine  kültürel ve dini olarak yakın hissetmesi toplumsal kabul düzeyini olumlu etkilemektedir. ABSTRACT IN ENGLISHAn evaluation of the European Union and Turkish policies regarding the culture of living togetherThis article aims to determine the level of social acceptance towards Syrians within the context of cohabitation culture by evaluating EU’s legal structure and public service initiatives in order to prevent Syrian refugees from being excluded in member and candidate countries and by revealing government policies on acceptance of Syrians as “guest” by Turkish society and minimizing the exclusion risks of them. This article consists of two main parts, one of which is based on the effects of law and practices preventing refugees and asylum seekers from social exclusion, and the other is on the results of social perception on Syrians in Sultanbeyli district of Istanbul. At the end of 5-years taking in Syrian War, it is obvious that most of more than 3 million Syrian with unregistered ones in Turkey are “here to stay”. From this point of view, the primary scope of policies should be specified in order to remove side effects of refugee phenomenon seen as weighty matter by bottoming out the exclusion towards those people. To avoid possible large-scale conflicts or civil wars in the future, the struggle with exclusion phenomenon plays a crucial role regarding Turkey’s sociological situation and developing policies. In the meaning of forming a model for Turkey, a subtitle in this article is about public services for European-wide legal acquis and practices carried out since 1970s in order to prevent any exclusion from the society. On the other hand, other subtitles are about legal infrastructure and practices like Common European Asylum and Immigration Policies presented in 2005, and Law on Foreigners and International Protection introduced in 2013. In the last part of the article, the results of a field survey carried out in a district of Istanbul were used to analyze the exclusion towards refugees in Turkey. A face-to-face survey was randomly conducted with 200 settled refugees in Sultanbeyli district of Istanbul, and their perceptions towards Syrian people under temporary protection were evaluated. According to the results, the level of acceptance for Syrians living in this district seems relatively high. The fact that Turkish people living in the same district feel close to Syrian refugees culturally and religiously affect their perception in a positive way: however, it is strikingly seen and understood that local residents cop an attitude on the refugees’ becoming Turkish citizens.

HOME VISITS DURING THE FIRST MONTH OF DELIVERY FOR RECENTLY DELIVERED WOMEN IN UTTAR PRADESH, INDIA

2020 ◽  
Vol 6 (5) ◽  
pp. 1183-1189
Author(s):  
Dr. Tridibesh Tripathy ◽  
Dr. Umakant Prusty ◽  
Dr. Chintamani Nayak ◽  
Dr. Rakesh Dwivedi ◽  
Dr. Mohini Gautam
Keyword(s):  
Large Scale ◽  
National Level ◽  
Uttar Pradesh ◽  
Life Time ◽  
Structured Interview ◽  
The Other ◽  
Registration System ◽  
Action Group ◽  
Current Article ◽  
The Impact

The current article of Uttar Pradesh (UP) is about the ASHAs who are the daughters-in-law of a family that resides in the same community that they serve as the grassroots health worker since 2005 when the NRHM was introduced in the Empowered Action Group (EAG) states. UP is one such Empowered Action Group (EAG) state. The current study explores the actual responses of Recently Delivered Women (RDW) on their visits during the first month of their recent delivery. From the catchment area of each of the 250 ASHAs, two RDWs were selected who had a child in the age group of 3 to 6 months during the survey. The response profiles of the RDWs on the post- delivery first month visits are dwelled upon to evolve a picture representing the entire state of UP. The relevance of the study assumes significance as detailed data on the modalities of postnatal visits are available but not exclusively for the first month period of their recent delivery. The details of the post-delivery first month period related visits are not available even in large scale surveys like National Family Health Survey 4 done in 2015-16. The current study gives an insight in to these visits with a five-point approach i.e. type of personnel doing the visit, frequency of the visits, visits done in a particular week from among those four weeks separately for the three visits separately. The current study is basically regarding the summary of this Penta approach for the post- delivery one-month period.     The first month period after each delivery deals with 70% of the time of the postnatal period & the entire neonatal period. Therefore, it does impact the Maternal Mortality Rate & Ratio (MMR) & the Neonatal Mortality Rates (NMR) in India and especially in UP through the unsafe Maternal & Neonatal practices in the first month period after delivery. The current MM Rate of UP is 20.1 & MM Ratio is 216 whereas the MM ratio is 122 in India (SRS, 2019). The Sample Registration System (SRS) report also mentions that the Life Time Risk (LTR) of a woman in pregnancy is 0.7% which is the highest in the nation (SRS, 2019). This means it is very risky to give birth in UP in comparison to other regions in the country (SRS, 2019). This risk is at the peak in the first month period after each delivery. Similarly, the current NMR in India is 23 per 1000 livebirths (UNIGME,2018). As NMR data is not available separately for states, the national level data also hold good for the states and that’s how for the state of UP as well. These mortalities are the impact indicators and such indicators can be reduced through long drawn processes that includes effective and timely visits to RDWs especially in the first month period after delivery. This would help in making their post-natal & neonatal stage safe. This is the area of post-delivery first month visit profile detailing that the current article helps in popping out in relation to the recent delivery of the respondents.   A total of four districts of Uttar Pradesh were selected purposively for the study and the data collection was conducted in the villages of the respective districts with the help of a pre-tested structured interview schedule with both close-ended and open-ended questions.  The current article deals with five close ended questions with options, two for the type of personnel & frequency while the other three are for each of the three visits in the first month after the recent delivery of respondents. In addition, in-depth interviews were also conducted amongst the RDWs and a total 500 respondents had participated in the study.   Among the districts related to this article, the results showed that ASHA was the type of personnel who did the majority of visits in all the four districts. On the other hand, 25-40% of RDWs in all the 4 districts replied that they did not receive any visit within the first month of their recent delivery. Regarding frequency, most of the RDWs in all the 4 districts received 1-2 times visits by ASHAs.   Regarding the first visit, it was found that the ASHAs of Barabanki and Gonda visited less percentage of RDWs in the first week after delivery. Similarly, the second visit revealed that about 1.2% RDWs in Banda district could not recall about the visit. Further on the second visit, the RDWs responded that most of them in 3 districts except Gonda district did receive the second postnatal visit in 7-15 days after their recent delivery. Less than half of RDWs in Barabanki district & just more than half of RDWs in Gonda district received the third visit in 15-21 days period after delivery. For the same period, the majority of RDWs in the rest two districts responded that they had been entertained through a home visit.

A new algorithm for finding CRM-model coefficients

2019 ◽  
Vol 5 (3) ◽  
pp. 164-185 ◽  
Author(s):  
Alexander D. Bekman ◽  
Sergey V. Stepanov ◽  
Alexander A. Ruchkin ◽  
Dmitry V. Zelenin
Keyword(s):  
Approximate Solution ◽  
Optimization Problem ◽  
Optimal Solution ◽  
Complex Form ◽  
Approximate Solutions ◽  
The Other ◽  
Programming Algorithm ◽  
Stochastic Algorithms ◽  
Large Set ◽  
Flow Rates

The quantitative evaluation of producer and injector well interference based on well operation data (profiles of flow rates/injectivities and bottomhole/reservoir pressures) with the help of CRM (Capacitance-Resistive Models) is an optimization problem with large set of variables and constraints. The analytical solution cannot be found because of the complex form of the objective function for this problem. Attempts to find the solution with stochastic algorithms take unacceptable time and the result may be far from the optimal solution. Besides, the use of universal (commercial) optimizers hides the details of step by step solution from the user, for example&nbsp;— the ambiguity of the solution as the result of data inaccuracy.<br> The present article concerns two variants of CRM problem. The authors present a new algorithm of solving the problems with the help of “General Quadratic Programming Algorithm”. The main advantage of the new algorithm is the greater performance in comparison with the other known algorithms. Its other advantage is the possibility of an ambiguity analysis. This article studies the conditions which guarantee that the first variant of problem has a unique solution, which can be found with the presented algorithm. Another algorithm for finding the approximate solution for the second variant of the problem is also considered. The method of visualization of approximate solutions set is presented. The results of experiments comparing the new algorithm with some previously known are given.

Should all Hypertensive Patients be Screened for Primary Aldosteronism?

2019 ◽  
Vol 15 (1) ◽  
pp. 54-56
Author(s):  
Stelina Alkagiet ◽  
Konstantinos Tziomalos
Keyword(s):  
Resistant Hypertension ◽  
Primary Aldosteronism ◽  
Large Scale ◽  
Controlled Trial ◽  
The Other ◽  
Limited Data ◽  
Hypertensive Patients ◽  
Randomized Controlled ◽  
Increased Risk ◽  
Prospective Randomized Controlled Trial

Primary aldosteronism (PA) is not only a leading cause of secondary and resistant hypertension, but is also quite frequent in unselected hypertensive patients. Moreover, PA is associated with increased cardiovascular risk, which is disproportionate to BP levels. In addition, timely diagnosis of PA and prompt initiation of treatment attenuate this increased risk. On the other hand, there are limited data regarding the usefulness of screening for PA in all asymptomatic or normokalemic hypertensive patients. More importantly, until now, no well-organized, large-scale, prospective, randomized controlled trial has proved the effectiveness of screening for PA for improving clinical outcome. Accordingly, until more relevant data are available, screening for PA should be considered in hypertensive patients with spontaneous or diuretic-induced hypokalemia as well as in those with resistant hypertension. However, screening for PA in all hypertensive patients cannot be currently recommended.

Talking about MOTION in Middle English

2017 ◽  
Author(s):  
Judith Huber
Keyword(s):  
Middle English ◽  
Old English ◽  
Language Contact ◽  
Large Scale ◽  
The Other ◽  
Motion Verbs ◽  
Text Type ◽  
Anglo Norman ◽  
Contact Situation ◽  
Analysis Of Motion

Chapter 6 begins with an overview of the language contact situation with (Anglo-) French and Latin, resulting in large-scale borrowing in the Middle English period. The analysis of 465 Middle English verbs used to express intransitive motion shows that there are far more French/Latin loans in the path verbs than in the other motion verbs. The range of (new) manner of motion verbs testifies to the manner salience of Middle English: caused motion verbs are also found in intransitive motion meanings, as are French loans which do not have motion uses in continental French. Their motion uses in Anglo-Norman are discussed in terms of contact influence of Middle English. The analysis of motion expression in different texts yields a picture similar to the situation in Old English, with path typically expressed in satellites, and neutral as well as manner of motion verbs being most frequent, depending on text type.

scholarly journals Massive and Microscopic Sensemaking During COVID-19 Times

2020 ◽  
pp. 107780042096247 ◽  
Author(s):  
Annette N. Markham ◽  
Anne Harris ◽  
Mary Elizabeth Luka
Keyword(s):  
Critical Pedagogy ◽  
Lived Experience ◽  
Large Scale ◽  
Ethic Of Care ◽  
Feminist Perspective ◽  
The Other ◽  
Self And Other ◽  
Planetary Scale ◽  
Making Sense ◽  
Ongoing Experiment

How does this pandemic moment help us to think about the relationships between self and other, or between humans and the planet? How are people making sense of COVID-19 in their everyday lives, both as a local and intimate occurrence with microscopic properties, and a planetary-scale event with potentially massive outcomes? In this paper we describe our approach to a large-scale, still-ongoing experiment involving more than 150 people from 26 countries. Grounded in autoethnography practice and critical pedagogy, we offered 21 days of self guided prompts to for us and the other participants to explore their own lived experience. Our project illustrates the power of applying a feminist perspective and an ethic of care to engage in open ended collaboration during times of globally-felt trauma.

scholarly journals Investigating the properties of a galaxy group at z = 0.6

2020 ◽  
Vol 15 (S359) ◽  
pp. 188-189
Author(s):  
Daniela Hiromi Okido ◽  
Cristina Furlanetto ◽  
Marina Trevisan ◽  
Mônica Tergolina
Keyword(s):  
Large Scale ◽  
The Other ◽  
Numerical Density ◽  
Spectroscopy Data ◽  
Stellar Kinematics ◽  
Galaxy Groups ◽  
The Galaxy ◽  
The Difference ◽  
The Impact ◽  
The Universe

AbstractGalaxy groups offer an important perspective on how the large-scale structure of the Universe has formed and evolved, being great laboratories to study the impact of the environment on the evolution of galaxies. We aim to investigate the properties of a galaxy group that is gravitationally lensing HELMS18, a submillimeter galaxy at z = 2.39. We obtained multi-object spectroscopy data using Gemini-GMOS to investigate the stellar kinematics of the central galaxies, determine its members and obtain the mass, radius and the numerical density profile of this group. Our final goal is to build a complete description of this galaxy group. In this work we present an analysis of its two central galaxies: one is an active galaxy with z = 0.59852 ± 0.00007, while the other is a passive galaxy with z = 0.6027 ± 0.0002. Furthermore, the difference between the redshifts obtained using emission and absorption lines indicates an outflow of gas with velocity v = 278.0 ± 34.3 km/s relative to the galaxy.

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