Aerodynamic and Thermo-Chemical Assessment of a Post-Catalyst Burnout Zone Liner

A Kawasaki Heavy Industries M1A-13X engine equipped with a Xonon® Cool Combustion System was used to assess the “effectiveness” of a post-catalyst burnout zone liner. The engine is currently installed at the City of Santa Clara’s Silicon Valley Power municipal electrical generating stations and connected to the grid. Post-catalyst burnout zone liner aero-thermal design and inlet boundary conditions play an important role in achieving low CO emissions. In this particular study, these parameters have been evaluated to minimize CO emissions (by maximizing CO burnout). An aero thermal analysis was conducted using Computational Fluid Dynamics (CFD) simulations of the liner for two distinct engine configurations. The analysis includes characterization of the inlet boundary conditions, heat transfer analysis, ignition delay time, liner residence time and the aerodynamic flow field. In addition, engine tests were used to measure and evaluate the impact of design features on CO emissions. Tests were conducted using new seal design and catalyst liner interface configurations. Results from both of these investigations were then used to determine the “effectiveness” of the liner. The CFD analysis and engine test data identified potential regions of improvement to maximize CO burnout in the Burn out Zone (BOZ) liner. These improvements included changing the inlet boundary conditions as well as modifying the BOZ geometry. Ultimately, a solution scheme was selected and changes were made to the catalyst seal design as well as the catalyst to container interface. Upon implementation, these changes yielded an improved effectiveness and extended the operating range of the engine by minimizing CO emissions.

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Numerical and experimental analyses for the improvement of surface instant decontamination technology through biocidal agent dispersion: Potential of application during pandemic

PLoS ONE ◽

10.1371/journal.pone.0251817 ◽

2021 ◽

Vol 16 (5) ◽

pp. e0251817

Author(s):

Paulo Roberto Freitas Neves ◽

Turan Dias Oliveira ◽

Tarcísio Faustino Magalhães ◽

Paulo Roberto Santana dos Reis ◽

Luzia Aparecida Tofaneli ◽

...

Keyword(s):

Experimental Tests ◽

Cfd Simulations ◽

New Device ◽

Qualitative And Quantitative ◽

Droplet Concentration ◽

Computational Fluid Dynamics Cfd ◽

Suspended Droplet ◽

The Impact ◽

Disinfection Chamber ◽

Important Form

The transmission of SARS-CoV-2 through contact with contaminated surfaces or objects is an important form of transmissibility. Thus, in this study, we evaluated the performance of a disinfection chamber designed for instantaneous dispersion of the biocidal agent solution, in order to characterize a new device that can be used to protect individuals by reducing the transmissibility of the disease through contaminated surfaces. We proposed the necessary adjustments in the configuration to improve the dispersion on surfaces and the effectiveness of the developed equipment. Computational Fluid Dynamics (CFD) simulations of the present technology with a chamber having six nebulizer nozzles were performed and validated through qualitative and quantitative comparisons, and experimental tests were conducted using the method Water-Sensitive Paper (WSP), with an exposure to the biocidal agent for 10 and 30 s. After evaluation, a new passage procedure for the chamber with six nozzles and a new configuration of the disinfection chamber were proposed. In the chamber with six nozzles, a deficiency was identified in its central region, where the suspended droplet concentration was close to zero. However, with the new passage procedure, there was a significant increase in wettability of the surface. With the proposition of the chamber with 12 nozzles, the suspended droplet concentration in different regions increased, with an average increase of 266%. The experimental results of the new configuration proved that there was an increase in wettability at all times of exposure, and it was more significant for an exposure of 30 s. Additionally, even in different passage procedures, there were no significant differences in the results for an exposure of 10 s, thereby showing the effectiveness of the new configuration or improved spraying and wettability by the biocidal agent, as well as in minimizing the impact caused by human factor in the performance of the disinfection technology.

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NESTED HIGH-RESOLUTION NOx AND PM SIMULATIONS OVER ZÜRICH

10.5194/egusphere-egu21-6202 ◽

2021 ◽

Author(s):

Ivo Suter ◽

Lukas Emmenegger ◽

Dominik Brunner

Keyword(s):

Air Pollution ◽

Air Quality ◽

Boundary Conditions ◽

Meteorological Conditions ◽

Model Systems ◽

Multi Scale ◽

Wide Range ◽

The Impact ◽

The City ◽

Concentration Levels

Reducing air pollution, which is the world's largest single environmental health risk, demands better-informed air quality policies. Consequently, multi-scale air quality models are being developed with the goal to resolve cities. One of the major challenges in such model systems is to accurately represent all large- and regional-scale processes that may critically determine the background concentration levels over a given city. This is particularly true for longer-lived species such as aerosols, for which background levels often dominate the concentration levels, even within the city. Furthermore, the heterogeneous local emissions, and complex dispersion in the city have to be considered carefully.In this study, the impact of processes across a wide range of scales on background concentrations over Switzerland and the city of Zurich was modelled by performing one year of nested European and Swiss national COSMO-ART simulations to obtain adequate boundary conditions for gas-phase chemical, aerosol and meteorological conditions for city-resolving simulations. The regional climate chemistry model COSMO-ART (Vogel et al. 2009) was used in a 1-way coupled mode. The outer, European, domain, which was driven by chemical boundary conditions from the global MOZART model, had a 6.6 km horizontal resolution and the inner, Swiss, domain one of 2.2 km. For the city scale, a catalogue of more than 1000 mesoscale flow patterns with 100 m resolution was created with the model GRAMM, based on a discrete set of atmospheric stabilities, wind speeds and directions, accounting for the influence of land-use and topography. Finally, the flow around buildings was solved with the CFD model GRAL forced at the boundaries by GRAMM. Subsequently, Lagrangian dispersion simulations for a set of air pollutants and emission sectors (traffic, industry, ...) based on extremely detailed building and emission data was performed in GRAL. The result of this nested procedure is a library of 3-dimensional air pollution maps representative of hourly situations in Zurich (Berchet et al. 2017). From these pre-computed situations, time-series and concentration maps can be obtained by selecting situations according to observed or modelled meteorological conditions.The results were compared to measurements from air quality monitoring network stations. Modelled concentrations of NOx and PM compared well to measurements across multiple locations, provided background conditions were considered carefully. The nested multi-scale modelling system COSMO-ART/GRAMM/GRAL can adequately reproduce local air quality and help understanding the relative contributions of local versus distant emissions, as well as fill the space between precise point measurements from monitoring sites. This information is useful for research, policy-making, and epidemiological studies particularly under the assumption that exceedingly high concentrations become more and more localised phenomenon in the future.

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De-risking flight trials using airwake simulations

10.24868/issn.2515-818x.2018.039 ◽

2018 ◽

Author(s):

C M Ward

Keyword(s):

Royal Navy ◽

Exposure Limits ◽

Cfd Simulations ◽

Real Time System ◽

Flow Features ◽

Operating Limits ◽

Turbulent Airflow ◽

Computational Fluid Dynamics Cfd ◽

The Impact ◽

Rotary Wing

Air operations around naval vessels are inherently challenging and a major contributor to this is the turbulent airflow around the vessels, colloquially known as the airwake. To manage the risks associated with these unsteady airflows and to help define safe operating limits for the ship and the aircraft, the Royal Navy undertakes First of Class Flight Trials (FOCFTs). However, these trials inherently carry their own risks as well as being costly and time consuming. This paper discusses how Computational Fluid Dynamics (CFD) simulations have been used to de-risk flight trials and operations on the Queen Elizabeth Class (QEC) carriers. The simulations are shown to be in excellent agreement with full-scale LiDAR and anemometer measurements, which provides the requisite confidence to use them as a basis for de-risking. To de-risk the rotary wing FOCFTs, the turbulence approach parameter was defined as a proxy for pilot workload. It is shown that this parameter can be used to identify the wind conditions that are likely to be the most difficult for pilots, and to advise on changes to the approach paths that would reduce pilot workload. Test pilots were briefed with this airwake information prior to the FOCFTs, and the flow features identified in the CFD were found to be consistent with the pilots’ experiences. In the future this analysis could be used to reduce the time and cost associated with flight trials, manage through-life risks, and assess the impact of design decisions on the airwake during ship design. The work has also been used to de-risk F-35 trials and operations. In particular, the findings show that it may be possible to extend the operating envelope of the aircraft using a novel real-time system to predict airwake turbulence. In addition, CFD simulations were used to de-risk ondeck operations by ensuring that aircraft are within their exposure limits when tied-down. This information was used by the FOCFTs teams during rotary wing trials.

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Impact of Blockage on the Hydrodynamic Performance of Oscillating-Foils Hydrokinetic Turbines

Journal of Fluids Engineering ◽

10.1115/1.4033298 ◽

2016 ◽

Vol 138 (9) ◽

Cited By ~ 10

Author(s):

Etienne Gauthier ◽

Thomas Kinsey ◽

Guy Dumas

Keyword(s):

Operating Conditions ◽

Hydrodynamic Performance ◽

Blockage Ratio ◽

Cfd Simulations ◽

Hydrokinetic Turbines ◽

Marine Energy ◽

Computational Fluid Dynamics Cfd ◽

The Impact ◽

Do So ◽

Oscillating Foils

This paper describes a study of the impact of confinement on the hydrodynamic performance of oscillating-foils hydrokinetic turbines (OFHT). This work aims to contribute to the development of standards applying to marine energy converters. These blockage effects have indeed to be taken into account when comparing measurements obtained in flumes, towing tanks, and natural sites. This paper provides appropriate correction formula to do so for OFHT based on computational fluid dynamics (CFD) simulations performed at a Reynolds Number Re = 3 × 106 for reduced frequencies between f* = 0.08 and f* = 0.22 considering area-based blockage ratios ranging from ε = 0.2% to 60%. The need to discriminate between the vertical and horizontal confinement and the impact of the foil position in the channel are also investigated and are shown to be of second-order as compared to the overall blockage level. As expected, it is confirmed that the power extracted by the OFHT increases with the blockage level. It is further observed that for blockage ratio of less than ε = 40%, the power extracted scales linearly with ε. The approach proposed to correlate the performance of the OFHT in different blockage conditions uses the correction proposed by Barnsley and Wellicome and assumes a linear relation between the power extracted and the blockage. This technique is shown to be accurate for most of the practical operating conditions for blockage ratios up to 50%.

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Maximization of Solar Gains of an Air Collector by Simulations

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.483 ◽

2013 ◽

Vol 284-287 ◽

pp. 483-487 ◽

Cited By ~ 1

Author(s):

Ondrej Sikula ◽

Vit Merka ◽

Jiri Hirs ◽

Josef Plášek

Keyword(s):

Heat Transfer ◽

Solar Energy ◽

Solar Collector ◽

Cfd Simulations ◽

Ansys Fluent ◽

Operation Conditions ◽

Flow And Heat Transfer ◽

Solar Air Collector ◽

Computational Fluid Dynamics Cfd ◽

The Impact

The paper deals with numerical simulations of the impact of design, shading, positioning and orientation of a solar air collector an efficiency of exploitation of solar energy. The solar collector is used to preheat of an air, which then is supplied into the building. There are various requirements for solar air collectors. We are focused on maximization of solar energy gain by optimizing geometry, orientation and positioning of a solar air collector. To achieve the desired objective was a combination of two methods used. The firs one is Computational Fluid Dynamics (CFD) simulations of flow and heat transfer by convection, conduction and radiation in software ANSYS Fluent. The second one is the numerical simulation of the annual operations of the collector in the software BSim. The result of this work is an optimal design and operation conditions of the air collector.

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CFD Simulations of Radioembolization: A Proof-of-Concept Study on the Impact of the Hepatic Artery Tree Truncation

Mathematics ◽

10.3390/math9080839 ◽

2021 ◽

Vol 9 (8) ◽

pp. 839

Author(s):

Unai Lertxundi ◽

Jorge Aramburu ◽

Julio Ortega ◽

Macarena Rodríguez-Fraile ◽

Bruno Sangro ◽

...

Keyword(s):

Hepatic Artery ◽

Liver Parenchyma ◽

Patient Specific ◽

Proof Of Concept ◽

Cfd Simulations ◽

Intraarterial Infusion ◽

Computational Fluid Dynamics Cfd ◽

The Impact ◽

Healthy Liver ◽

Simulation Time

Radioembolization (RE) is a treatment for patients with liver cancer, one of the leading cause of cancer-related deaths worldwide. RE consists of the transcatheter intraarterial infusion of radioactive microspheres, which are injected at the hepatic artery level and are transported in the bloodstream, aiming to target tumors and spare healthy liver parenchyma. In paving the way towards a computer platform that allows for a treatment planning based on computational fluid dynamics (CFD) simulations, the current simulation (model preprocess, model solving, model postprocess) times (of the order of days) make the CFD-based assessment non-viable. One of the approaches to reduce the simulation time includes the reduction in size of the simulated truncated hepatic artery. In this study, we analyze for three patient-specific hepatic arteries the impact of reducing the geometry of the hepatic artery on the simulation time. Results show that geometries can be efficiently shortened without impacting greatly on the microsphere distribution.

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Test and Simulation of the Effects of Surface Roughness on a Shrouded Centrifugal Impeller

Volume 2D: Turbomachinery ◽

10.1115/gt2014-25480 ◽

2014 ◽

Cited By ~ 1

Author(s):

William T. Cousins ◽

Lei Yu ◽

Jacquelynn Garofano ◽

Barbara Botros ◽

Vishnu Sishtla ◽

...

Keyword(s):

Surface Roughness ◽

Cfd Simulation ◽

Centrifugal Impeller ◽

Test Results ◽

Cfd Simulations ◽

Computational Fluid Dynamics Cfd ◽

The Common ◽

R Value ◽

The Impact ◽

Grain Roughness

Surface roughness is an important parameter in the operational efficiency and loss development of turbomachinery components. Many computational fluid dynamics (CFD) simulations are performed on turbomachinery, but often one of the common assumptions is that the surfaces are hydraulically smooth. In this work, examination of the surfaces of two cast impellers is performed and compared to machined impellers with smoother surfaces. Both impeller sets were run in a two-stage industrial chiller unit using R134a refrigerant. Test results are presented and the impact of surface roughness modeling on the design is reviewed. Also discussed is the theory of the impact of roughness on turbulent boundary layers. Details about providing the CFD simulation with the proper sand grain roughness is discussed when surface finish (R-value) in microinches (μin) is measured.

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Characterization of the impact on the society of the local cisco networking academy of ITSA in Barranquilla

Bulletin of Social Informatics Theory and Application ◽

10.31763/businta.v4i1.259 ◽

2020 ◽

Vol 4 (1) ◽

pp. 21-34

Author(s):

Leonel Hernandez ◽

Piedad Marchena ◽

Aji Prasetya Wibawa

Keyword(s):

Caribbean Region ◽

Local Society ◽

The Caribbean ◽

New Challenges ◽

The University ◽

The Impact ◽

The City ◽

A Company ◽

Day By Day

By 1997, Cisco Systems, a company already consolidated in the technology and communications market, saw the need to train personnel who had the skills to configure, manage, install and support all its products in general at all levels, from design to the implementation of solutions. In Colombia, more precisely in the city of Barranquilla, the ITSA University Institution in the early 2000s saw an excellent opportunity to ally with the University created by Cisco, called Cisco Networking Academy, to train professionals in the Caribbean region capable of face the new challenges that technology in networks is generating day by day, becoming in the first Institution of higher education in the region to provide this type of training with international certification and endorsement. From then on, the local Cisco academy has strengthened and significantly impacted local society, generating valued and skilled labor in the labor market of the city and the region. The purpose of this work is to measure this impact, focused on the Cisco, CCNA, and CCNP flagship courses between 2015 and 2019, verifying how ITSA, through the Cisco Academy, has transformed lives. The research methodology is descriptive, exploratory, and documentary

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Use of Computational Fluid Dynamics for the Replication of Clinical Blood Flow and Pressure Measurements and Characterization of Hemodynamics in the Normal Ascending and Thoracic Aorta

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-176447 ◽

2007 ◽

Author(s):

John F. LaDisa ◽

C. Alberto Figueroa ◽

Irene E. Vignon-Clementel ◽

Frandics P. Chan ◽

Jeffrey A. Feinstein ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Blood Flow ◽

Boundary Conditions ◽

Thoracic Aorta ◽

Vascular Anatomy ◽

Data Set ◽

Cfd Models ◽

Computational Fluid Dynamics Cfd

Complications associated with abnormalities of the ascending and thoracic aorta are directly influenced by mechanical forces. To understand hemodynamic alterations associated with diseases in this region, however, we must first characterize related indices during normal conditions. Computational fluid dynamics (CFD) models of the ascending and thoracic aorta to date have only provided descriptions of the velocity field using idealized representations of the vasculature, a single patient data set, and outlet boundary conditions that do not replicate physiologic blood flow and pressure. Importantly, the complexity of aortic flow patterns, limited availability of methods for implementing appropriate boundary conditions, and ability to replicate vascular anatomy all contribute to the difficulty of the problem and, likely, the scarcity of more detailed studies.

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