Effects of Non-Uniform Combustor Exit Flow on Turbine Aerodynamics

2012 ◽  
Author(s):  
Stavros Pyliouras ◽  
Heinz-Peter Schiffer ◽  
Erik Janke ◽  
Lars Willer
Keyword(s):  
Boundary Condition ◽  
Test Rig ◽  
Lean Burn ◽  
Lean Combustion ◽  
Flow Mechanisms ◽  
Low Nox Combustion ◽  
Inhomogeneous Temperature ◽  
The Impact ◽  
Inlet Boundary Condition ◽  
Insight Into

Very-low NOx combustion concepts require a high swirl number of the flow in the combustion chamber to allow for lean burn combustion. This article deals with the influence of the resulting combustor exit swirl on the turbine aerodynamics of the first stage. This investigation is based on numerical simulations. According to the literature research additional insight into combustor-turbine interaction is achieved by taking into account a fully two dimensional inlet boundary condition. Up to now published results on combustor-turbine interaction were mostly restricted to the inhomogeneous temperature distribution at the turbine inlet. The investigations are carried out on a real engine geometry — the E3E Core 3/2 — a research project of Rolls-Royce Deutschland on lean combustion. Calculations are conducted by means of the Rolls-Royce plc code Hydra. The swirled inlet boundary condition is further scaled to test rig conditions to check for the transferability between the test rig and the real engine geometry. The results show a significant impact of the inhomogeneous turbine inflow on the stage efficiency and the thermal load. The optimization potential due to the clocking position of the combustor swirl is analyzed. The impact on the secondary flow mechanisms is analyzed with a novel visualization technique. A frequency spectrum analysis is carried out to investigate the effects of the 2D inlet boundary condition on the rotor row.

scholarly journals Commissioning of a Combined Hot-Streak and Swirl Profile Generator in a Transonic Turbine Test Facility

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Maxwell G. Adams ◽  
Thomas Povey ◽  
Benjamin F. Hall ◽  
David N. Cardwell ◽  
Kam S. Chana ◽  
...  
Keyword(s):  
Boundary Condition ◽  
Reynolds Number ◽  
Gas Turbines ◽  
Test Facility ◽  
Lean Burn ◽  
Numerical Predictions ◽  
Turbine Inlet ◽  
Total Temperature ◽  
Inlet Conditions ◽  
Inlet Boundary Condition

Abstract By enhancing the premixing of fuel and air prior to combustion, recently developed lean-burn combustor systems have led to reduced NOx and particulate emissions in gas turbines. Lean-burn combustor exit flows are typically characterized by nonuniformities in total temperature, or so-called hot-streaks, swirling velocity profiles, and high turbulence intensity. While these systems improve combustor performance, the exiting flow-field presents significant challenges to the aerothermal performance of the downstream turbine. This paper presents the commissioning of a new fully annular lean-burn combustor simulator for use in the Oxford Turbine Research Facility (OTRF), a transonic rotating facility capable of matching nondimensional engine conditions. The combustor simulator can deliver engine-representative turbine inlet conditions featuring swirl and hot-streaks either separately or simultaneously. To the best of our knowledge, this simulator is the first of its kind to be implemented in a rotating turbine test facility.The combustor simulator was experimentally commissioned in two stages. The first stage of commissioning experiments was conducted using a bespoke facility exhausting to atmospheric conditions (Hall and Povey, 2015, “Experimental Study of Non-Reacting Low NOx Combustor Simulator for Scaled Turbine Experiments,” ASME Paper No. GT2015-43530.) and included area surveys of the generated temperature and swirl profiles. The survey data confirmed that the simulator performed as designed, reproducing the key features of a lean-burn combustor. However, due to the hot and cold air mixing process occurring at lower Reynolds number in the facility, there was uncertainty concerning the degree to which the measured temperature profile represented that in OTRF. The second stage of commissioning experiments was conducted with the simulator installed in the OTRF. Measurements of the total temperature field at turbine inlet and of the high-pressure (HP) nozzle guide vane (NGV) loading distributions were obtained and compared to measurements with uniform inlet conditions. The experimental survey results were compared to unsteady numerical predictions of the simulator at both atmospheric and OTRF conditions. A high level of agreement was demonstrated, indicating that the Reynolds number effects associated with the change to OTRF conditions were small. Finally, data from the atmospheric test facility and the OTRF were combined with the numerical predictions to provide an inlet boundary condition for numerical simulation of the test turbine stage. The NGV loading measurements show good agreement with the numerical predictions, providing validation of the stage inlet boundary condition imposed. The successful commissioning of the simulator in the OTRF will enable future experimental studies of lean-burn combustor–turbine interaction.

Effect of Various Tip Clearance Squealer Design on Turbine Stage Efficiency

2015 ◽  
Author(s):  
Nikolay Lomakin ◽  
Andrey Granovskiy ◽  
Vladimir Shchaulov ◽  
Jaroslaw Szwedowicz
Keyword(s):  
Tip Clearance ◽  
Navier Stokes ◽  
Radial Clearance ◽  
Turbine Stage ◽  
Test Rig ◽  
Numerical Investigations ◽  
Blade Cascade ◽  
The Impact ◽  
Stage Efficiency ◽  
Insight Into

This paper presents investigation of nine tip squealer design variants based on full 3D Navier-Stokes CFD calculations. In particular two main design features have been studied: the impact of relative squealer cavity rim extension and the impact of pressure side squealer cavity rim inclination on stage efficiency. All these cases have been compared for two values of relative radial gaps 0.6% and 1.36%. Obtained numerical results were validated against the experimental data measured on the E3 blade cascade test rig given in the open literature. As the overall outcome for these numerical investigations two zones with different vortex structures and different sealing features have been found. Moreover the size of these zones determines the level of the tip clearance leakage and losses for various tip squealer designs. The obtained loss values and corresponding change of the stage efficiency level as well as flow structure details were compared for all studied cases, providing insight into turbine stage aerodynamics with respect to minimal and maximal radial clearance.

Evaluation of the Numerical Modelling of a High Pressure Turbine Test Rig

2019 ◽  
Author(s):  
David Luquet ◽  
Francois Julienne ◽  
Aurélien Arntz ◽  
Eric Lippinois
Keyword(s):  
High Pressure ◽  
Infrared Imaging ◽  
Guide Vane ◽  
Fuel Efficiency ◽  
Temporal Variations ◽  
Test Rig ◽  
High Pressure Turbine ◽  
Lean Burn ◽  
Multi Stage ◽  
The Impact

Abstract To improve the fuel efficiency demanded by airlines and regulations, the turbomachinery industry is required to steadily enhance engine performances and numerical prediction capabilities. One of the solutions is the lean burn combustor which dramatically reduces NOx levels compared to rich one. However, one drawback of this technology is its impact on the High-pressure turbine due to large swirl and reduced cooling airflow, inducing large spatial and temporal variations in the turbine inlet condition. This can drastically change the operation of the turbine and our ability to model it using standard practice, usually RANS computation. To investigate this combustor-turbine interaction, the European Commission-funded project FACTOR (Full Aerothermal Combustor-Turbine interactiOns Research) was launched several years ago. A test rig of a combustor simulator coupled with a 1.5 stage turbine was built at a DLR facility. An extensive test campaign comprising 5 holes probes and infrared imaging was performed. These produced an array of aerodynamic quantities at different points of interest along the machine axis. With this project reaching its term by the end of 2017, results have been disseminated to the partners. This allows a comparison of measurements with RANS modeling on this configuration. The present paper deals with this analysis using several RANS computations and the results of the test campaign. First, single row computation of the Nozzle Guide Vane and rotor blade were performed. To impose the boundary conditions, the experimental map were azimuthally averaged to obtain profiles of total temperature, total pressure and flow angles. Second, the impact of some geometrical features was investigated. This was done using the recent addition of unstructured mesh capability in the elsA solver. Finally, multi-stage computations, both steady (mixing plane) and unsteady (sliding mesh) give an insight on the relative accuracy of these interstage models. All these computations were then used to investigate the behavior of this particular turbine. In addition to classical analysis using profiles of averaged data, the loss sources were identified by computing the viscous and thermal entropy production. This paves the way for a better understanding of the possibilities and limitations of our simulation capabilities.

scholarly journals Changing landscapes: Gay men in the west and northwest of Ireland

Sexualities ◽  
2020 ◽  
pp. 136346072098169
Author(s):  
Aidan McKearney
Keyword(s):  
Gay Men ◽  
Social Rights ◽  
Irish Society ◽  
Recent Past ◽  
Same Sex ◽  
Lgbt People ◽  
The Many ◽  
Northwest Region ◽  
The Impact ◽  
Insight Into

This article focuses on the experiences of gay men in the rural west and northwest region of Ireland, during a period of transformational social and political change in Irish society. These changes have helped facilitate new forms of LGBTQI visibility, and local radicalism in the region. Same-sex weddings, establishment of rural LGBT groups and marching under an LGBT banner at St Patricks Day parades would have been unthinkable in the recent past; but they are now becoming a reality. The men report continuing challenges in their lives as gay men in the nonmetropolitan space, but the emergence of new visibility, voice and cultural acceptance of LGBT people is helping change their lived experiences. The study demonstrates the impact of local activist LGBT citizens. Through their testimonies we can gain an insight into the many, varied and interwoven factors that have interplayed to create the conditions necessary for the men to: increasingly define themselves as gay to greater numbers of people in their localities; to embrace greater visibility and eschew strategies of silence; and aspire to a host of legal, political, cultural and social rights including same-sex marriage. Organic forms of visibility and local radicalism have emerged in the region and through an analysis of their testimonies we can see how the men continue to be transformed by an ever-changing landscape.

Double, triple or quadruple hits? Exploring the impact of cybercrime on victims in the Netherlands

2021 ◽  
pp. 026975802110106
Author(s):  
Raoul Notté ◽  
E.R. Leukfeldt ◽  
Marijke Malsch
Keyword(s):  
Public Opinion ◽  
Literature Review ◽  
The Netherlands ◽  
Public Discourse ◽  
Moral Judgments ◽  
Victim Blaming ◽  
High Prevalence ◽  
Different Types ◽  
The Impact ◽  
Insight Into

This article explores the impact of online crime victimisation. A literature review and 41 interviews – 19 with victims and 22 with experts – were carried out to gain insight into this. The interviews show that most impacts of online offences correspond to the impacts of traditional offline offences. There are also differences with offline crime victimisation. Several forms of impact seem to be specific to victims of online crime: the substantial scale and visibility of victimhood, victimisation that does not stop in time, the interwovenness of online and offline, and victim blaming. Victims suffer from double, triple or even quadruple hits; it is the accumulation of different types of impact, enforced by the limitlessness in time and space, which makes online crime victimisation so extremely invasive. Furthermore, the characteristics of online crime victimisation greatly complicate the fight against and prevention of online crime. Finally, the high prevalence of cybercrime victimisation combined with the severe impact of these crimes seems contradictory with public opinion – and associated moral judgments – on victims. Further research into the dominant public discourse on victimisation and how this affects the functioning of the police and victim support would be valuable.

scholarly journals Using syndromic measures of mortality to capture the dynamics of COVID-19 in Java, Indonesia, in the context of vaccination rollout

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Bimandra A. Djaafara ◽  
Charles Whittaker ◽  
Oliver J. Watson ◽  
Robert Verity ◽  
Nicholas F. Brazeau ◽  
...  
Keyword(s):  
Rural Areas ◽  
Vaccination Campaign ◽  
Control Measures ◽  
Additional Insight ◽  
Short Term ◽  
If Current ◽  
Vaccine Impact ◽  
Potential Impact ◽  
The Impact ◽  
Insight Into

Abstract Background As in many countries, quantifying COVID-19 spread in Indonesia remains challenging due to testing limitations. In Java, non-pharmaceutical interventions (NPIs) were implemented throughout 2020. However, as a vaccination campaign launches, cases and deaths are rising across the island. Methods We used modelling to explore the extent to which data on burials in Jakarta using strict COVID-19 protocols (C19P) provide additional insight into the transmissibility of the disease, epidemic trajectory, and the impact of NPIs. We assess how implementation of NPIs in early 2021 will shape the epidemic during the period of likely vaccine rollout. Results C19P burial data in Jakarta suggest a death toll approximately 3.3 times higher than reported. Transmission estimates using these data suggest earlier, larger, and more sustained impact of NPIs. Measures to reduce sub-national spread, particularly during Ramadan, substantially mitigated spread to more vulnerable rural areas. Given current trajectory, daily cases and deaths are likely to increase in most regions as the vaccine is rolled out. Transmission may peak in early 2021 in Jakarta if current levels of control are maintained. However, relaxation of control measures is likely to lead to a subsequent resurgence in the absence of an effective vaccination campaign. Conclusions Syndromic measures of mortality provide a more complete picture of COVID-19 severity upon which to base decision-making. The high potential impact of the vaccine in Java is attributable to reductions in transmission to date and dependent on these being maintained. Increases in control in the relatively short-term will likely yield large, synergistic increases in vaccine impact.

Insight into the impact of EGFR L792Y/F/H mutations on sensitivity to osimertinib: an in silico study

2021 ◽  
Vol 45 (10) ◽  
pp. 4756-4765
Author(s):  
Daoxing Chen ◽  
Liting Zhang ◽  
Yanan Liu ◽  
Jiali Song ◽  
Jingwen Guo ◽  
...  
Keyword(s):  
In Silico ◽  
In Silico Study ◽  
The Impact ◽  
Insight Into

EGFR L792Y/F/H mutation makes it difficult for Osimertinib to recognize ATP pockets.

The RUMA Alliance targets: an overview

Livestock ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 176-179
Author(s):  
Chris Lloyd
Keyword(s):  
Task Force ◽  
Animal Health ◽  
Antibiotic Use ◽  
Codes Of Practice ◽  
The Government ◽  
The Uk ◽  
Ongoing Support ◽  
The Impact ◽  
Insight Into ◽  
Roll Out

The Responsible Use of Medicines in Agriculture Alliance (RUMA) was established to promote the highest standards of food safety, animal health and animal welfare in the British livestock industry. It has a current focus to deliver on the Government objective of identifying sector-specific targets for the reduction, refinement or replacement of antibiotics in animal agriculture. The creation and roll out of sector specific targets in 2017 through the RUMA Targets Task Force, has helped focus activity across the UK livestock sectors to achieve a 50% reduction in antibiotic use since 2014. This has been realised principally through voluntary multi-sector collaboration, cross sector initiatives, codes of practice, industry body support and farm assurance schemes. This article provides an overview of RUMA's work to date providing insight into the methods used to create the targets, why they are so important, the impact they are having and how ongoing support and robust data are vital components in achieving the latest set of targets.

scholarly journals The Impact of Spaceflight and Microgravity on the Human Islet-1+ Cardiovascular Progenitor Cell Transcriptome

2021 ◽  
Vol 22 (7) ◽  
pp. 3577
Author(s):  
Victor Camberos ◽  
Jonathan Baio ◽  
Ana Mandujano ◽  
Aida F. Martinez ◽  
Leonard Bailey ◽  
...  
Keyword(s):  
Early Stage ◽  
Space Station ◽  
Cardiovascular Development ◽  
Support Cell ◽  
Cell Transcriptome ◽  
Islet 1 ◽  
Life On Earth ◽  
The Impact ◽  
And Oxidative Stress ◽  
Insight Into

Understanding the transcriptomic impact of microgravity and the spaceflight environment is relevant for future missions in space and microgravity-based applications designed to benefit life on Earth. Here, we investigated the transcriptome of adult and neonatal cardiovascular progenitors following culture aboard the International Space Station for 30 days and compared it to the transcriptome of clonally identical cells cultured on Earth. Cardiovascular progenitors acquire a gene expression profile representative of an early-stage, dedifferentiated, stem-like state, regardless of age. Signaling pathways that support cell proliferation and survival were induced by spaceflight along with transcripts related to cell cycle re-entry, cardiovascular development, and oxidative stress. These findings contribute new insight into the multifaceted influence of reduced gravitational environments.

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