A methodology for loss and performance assessment of a variable geometry turbocharger turbine through a new meanline FORTRAN program

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ahmed Ketata ◽  
Zied Driss
Keyword(s):  
Rotational Speed ◽  
Internal Combustion Engines ◽  
Maximum Efficiency ◽  
Variable Geometry ◽  
Mixed Flow ◽  
Content Type ◽  
Variable Geometry Turbocharger ◽  
Nozzle Vane ◽  
Wide Range ◽  
Vane Angle

PurposeVariable geometry turbine (VGT), a key component of modern internal combustion engines (ICE) turbochargers, is increasingly used for better efficiency and reduced exhaust gas emissions. The aim of this study is the development of a new meanline FORTRAN code for accurate performance and loss assessment of VGTs under a wider operating range. This code is a useful alternative tool for engineers for fast design of VGT systems where higher efficiency and minimum loss are being required.Design/methodology/approachThe proposed meanline code was applied to a variable geometry mixed flow turbine at different nozzle vane angles and under a wide range of rotational speed and the expansion ratio. The numerical methodology was validated through a comparison of the predicted performance to test data. The maps of the mass flow rate as well as the efficiency of the VGT system are discussed for different nozzle vane angles under a wide range of rotational speed. Based on the developed model, a breakdown loss analysis was carried out showing a significant effect of the nozzle vane angle on the loss distribution.FindingsResults indicated that the nozzle angle of 70° has led to the maximum efficiency compared to the other investigated nozzle vane angles ranging from 30° up to 80°. The results showed that the passage loss was significantly reduced as the nozzle vane angle increases from 30° up to 70°.Originality/valueThis paper outlines a new meanline approach for variable geometry turbocharger turbines. The developed code presents the novelty of including the effect of the vane radii variation, due to the pivoting mechanism of the nozzle ring. The developed code can be generalized to either radial or mixed flow turbines with or without a VGT system.

Simulation of a Diesel Engine with Variable Geometry Turbocharger and Parametric Study of Variable Vane Position on Engine Performance

2017 ◽  
Vol 67 (4) ◽  
pp. 375 ◽  
Author(s):  
Anand Mammen Thomas ◽  
Jensen Samuel J. ◽  
Paul Pramod M. ◽  
A. Ramesh ◽  
R. Murugesan ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Parametric Study ◽  
Thermodynamic Simulation ◽  
Weight Ratio ◽  
Engine Performance ◽  
Boost Pressure ◽  
Variable Geometry ◽  
Variable Geometry Turbocharger ◽  
Additional Degree ◽  
Wide Range

Modelling of a turbocharger is of interest to the engine designer as the work developed by the turbine can be used to drive a compressor coupled to it. This positively influences charge air density and engine power to weight ratio. Variable geometry turbocharger (VGT) additionally has a controllable nozzle ring which is normally electro-pneumatically actuated. This additional degree of freedom offers efficient matching of the effective turbine area for a wide range of engine mass flow rates. Closing of the nozzle ring (vanes tangential to rotor) result in more turbine work and deliver higher boost pressure but it also increases the back pressure on the engine induced by reduced turbine effective area. This adversely affects the net engine torque as the pumping work required increases. Hence, the optimum vane position for a given engine operating point is to be found through simulations or experimentation. A thermodynamic simulation model of a 2.2l 4 cylinder diesel engine was developed for investigation of different control strategies. Model features map based performance prediction of the VGT. Performance of the engine was simulated for steady state operation and validated with experimentation. The results of the parametric study of VGT’s vane position on the engine performance are discussed.

Study on the Modes of Operation of a Multi-Machine Installations with Mechanical Reduction

2019 ◽  
pp. 12-22
Author(s):  
A. M. Oleynikov ◽  
L. N. Kanov
Keyword(s):  
Mathematical Description ◽  
Reactive Power ◽  
Maximum Efficiency ◽  
Wind Flow ◽  
System Of Equations ◽  
Mechanical Equilibrium ◽  
Synchronous Generators ◽  
Electromagnetic Excitation ◽  
Number Of Generators ◽  
Wide Range

The paper gives the description of the original wind electrical installation with mechanical reduction in which the output of vertical axis wind turbine with rather low rotation speed over multiplicator is distributed to a certain number of generators. The number of acting generators is determined by the output of actual operating wind stream at each moment. According to this constructive scheme, it is possible to provide effective and with maximum efficiency installation work in a wide range of wind speeds and under any schedule issued to the consumer of electricity. As there are no any experience in using such complexes, mathematical description of its main elements is given, namely windwheels, generators with electromagnetic excitation of magnetic electrical type, then their interaction with windwheel, and also the results of mathematical modeling of work system regimes under using the offered system of equations. The basis for the mathematical description of the main elements of the installation – synchronous generators – are the system of equations of electrical and mechanical equilibrium in relative units in rotating coordinates without considering saturation of the magnetic circuit. The equation of mechanical equilibrium systems includes torque and brake windwheel electromagnetic moments of generators with taking into account the reduction coefficients and friction. In addition, we specify the alternator rotor dynamics resulting from continuous torque of windwheel fluctuations under the influence of unsteady wind flow and wind speed serving as the original variable is modeled by a set of sinusoids. Model simplification is achieved by equivalization of similar generators and by disregarding these transitions with a small time constant. Calculation the installation with synchronous generators of two types of small and medium capacity taking into account the operational factors allowed us to demonstrate the logic of interactions in the main elements of the reported complex in the process of converting wind flow into the generated active and reactive power. We have shown the possibility of stable system work under changeable wind stream condition by regulating of the plant blade angle and with simultaneous varying of generator number of different types. All these are in great interest for project organizations and power producers.

scholarly journals Transfer of Plasmid DNA to Clinical Coagulase-Negative Staphylococcal Pathogens by Using a Unique Bacteriophage

2015 ◽  
Vol 81 (7) ◽  
pp. 2481-2488 ◽  
Author(s):  
Volker Winstel ◽  
Petra Kühner ◽  
Bernhard Krismer ◽  
Andreas Peschel ◽  
Holger Rohde
Keyword(s):  
Plasmid Dna ◽  
Genetic Manipulation ◽  
Current Knowledge ◽  
Virulence Determinants ◽  
Coagulase Negative Staphylococci ◽  
Reliable Technique ◽  
Content Type ◽  
Research Activities ◽  
Wide Range ◽  
Genetic Barriers

ABSTRACTGenetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a uniqueStaphylococcus aureusstrain via a specificS. aureusbacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinicalStaphylococcus epidermidisisolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.

scholarly journals Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Susan L. Brockmeier ◽  
Crystal L. Loving ◽  
Tracy L. Nicholson ◽  
Jinhong Wang ◽  
Sarah E. Peters ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccine Trial ◽  
Streptococcus Suis ◽  
Protein Subunit ◽  
Content Type ◽  
Degree Of Protection ◽  
Wide Range ◽  
Associated Proteins ◽  
Clinical Protection ◽  
Cellular Immune

ABSTRACT Streptococcus suis is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of S. suis protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins. Five candidate proteins were selected for evaluation in a vaccine trial and administered both intranasally and intramuscularly with one of two different adjuvant formulations. Clinical protection was evaluated by subsequent intranasal challenge with virulent S. suis . While subunit vaccination with the S. suis proteins induced IgG antibodies to each individual protein and a cellular immune response to the pool of proteins and provided substantial protection from challenge with virulent S. suis , the immune response elicited and the degree of protection were dependent on the parenteral adjuvant given. Subunit vaccination induced IgG reactive against different S. suis serotypes, indicating a potential for cross protection.

scholarly journals Hybrid ZnO/MoS2 Core/Sheath Heterostructures for Photoelectrochemical Water Splitting

Applied Nano ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 148-161
Author(s):  
Katerina Govatsi ◽  
Aspasia Antonelou ◽  
Labrini Sygellou ◽  
Stylianos G. Neophytides ◽  
Spyros N. Yannopoulos
Keyword(s):  
Visible Light ◽  
Wide Band ◽  
Nanowire Arrays ◽  
Maximum Efficiency ◽  
Light Illumination ◽  
Wide Band Gap ◽  
Long Term Stability ◽  
Visible Light Illumination ◽  
Nanowire Surface ◽  
Wide Range

The rational synthesis of semiconducting materials with enhanced photoelectrocatalytic efficiency under visible light illumination is a long-standing issue. ZnO has been systematically explored in this field, as it offers the feasibility to grow a wide range of nanocrystal morphology; however, its wide band gap precludes visible light absorption. We report on a novel method for the controlled growth of semiconductor heterostructures and, in particular, core/sheath ZnO/MoS2 nanowire arrays and the evaluation of their photoelectrochemical efficiency in oxygen evolution reaction. ZnO nanowire arrays, with a narrow distribution of nanowire diameters, were grown on FTO substrates by chemical bath deposition. Layers of Mo metal at various thicknesses were sputtered on the nanowire surface, and the Mo layers were sulfurized at low temperature, providing in a controlled way few layers of MoS2, in the range from one to three monolayers. The heterostructures were characterized by electron microscopy (SEM, TEM) and spectroscopy (XPS, Raman, PL). The photoelectrochemical properties of the heterostructures were found to depend on the thickness of the pre-deposited Mo film, exhibiting maximum efficiency for moderate values of Mo film thickness. Long-term stability, in relation to similar heterostructures in the literature, has been observed.

The role of organizational culture in the knowledge management process

2015 ◽  
Vol 19 (3) ◽  
pp. 433-455 ◽  
Author(s):  
Christina Ling-hsing Chang ◽  
Tung-Ching Lin
Keyword(s):  
Organizational Culture ◽  
Knowledge Management ◽  
Customer Service ◽  
Survey Methodology ◽  
Cultural Dimensions ◽  
Content Type ◽  
Knowledge Resources ◽  
Positive Effects ◽  
Wide Range ◽  
The Individual

Purpose – The purpose of the study is to focus on the enhancement of knowledge management (KM) performance and the relationship between organizational culture and KM process intention of individuals because of the diversity of organizational cultures (which include results-oriented, tightly controlled, job-oriented, closed system and professional-oriented cultures). Knowledge is a primary resource in organizations. If firms are able to effectively manage their knowledge resources, then a wide range of benefits can be reaped such as improved corporate efficiency, effectiveness, innovation and customer service. Design/methodology/approach – The survey methodology, which has the ability to enhance generalization of results (Dooley, 2001), was used to collect the data utilized in the testing of the research hypotheses. Findings – Results- and job-oriented cultures have positive effects on employee intention in the KM process (creation, storage, transfer and application), whereas a tightly controlled culture has negative effects. Research limitations/implications – However, it would have been better to use a longitudinal study to collect useful long-term data to understand how the KM process would be influenced when organizational culture dimensions are changed through/by management. This is the first limitation of this study. According to Mason and Pauleen (2003), KM culture is a powerful predictor of individual knowledge-sharing behavior, which is not included in this study. Thus, this is the second limitation of this paper. Moreover, national culture could be an important issue in the KM process (Jacks et al., 2012), which is the third limitation of this paper for not comprising it. Practical implications – In researchers’ point of view, results- and job-oriented cultures have positive effects, whereas a tightly controlled culture has a negative effect on the KM process intention of the individual. These findings provide evidences that challenge the perspective of Kayworth and Leidner (2003) on this issue. As for practitioners, management has a direction to modify their organizational culture to improve the performance of KM process. Social implications – Both behavioral and value perspectives of the organizational cultural dimensions (results-oriented, tightly control, job-oriented, sociability, solidarity, need for achievement and democracy) should be examined to ascertain their effects firstly on KM culture and then on the KM process intention of the individual. It is hoped that the current study will spawn future investigations that lead to the development of an integrated model which includes organizational culture, KM culture and the KM process intention of the individual. Originality/value – The results-oriented, loosely controlled and job-oriented cultures will improve the effectiveness of the KM process and will also increase employees’ satisfaction and willingness to stay with the organization.

From digital citizen to digital professional

Kybernetes ◽  
2019 ◽  
Vol 48 (7) ◽  
pp. 1463-1477
Author(s):  
Olga Marino ◽  
Jaime Andres Gutierrez ◽  
Sandra Aguirre
Keyword(s):  
Information And Communication Technologies ◽  
Communication Technologies ◽  
Cutting Edge ◽  
Case Study Methodology ◽  
Content Type ◽  
Innovative Strategy ◽  
Global Issues ◽  
Wide Range ◽  
Information And Communication ◽  
Teaching Learning

Purpose This paper aims to propose and evaluate a pedagogically sound and innovative strategy to teach a higher education course that prepares future professionals to intelligently use information and communication technologies (ICTs) in their personal and professional lives. Design/methodology/approach The conceptual framework used for the design of the course was the socio-constructivism and activity theories. The implementation of the course was evaluated using the intrinsic case study methodology by including several instruments. Findings The pedagogical strategy proposed proved to be sound, as the evaluation showed that students were able to describe, use and propose innovative uses of a wide range of cutting-edge technologies in their both everyday lives and professional settings; they also had the skills to analyse the opportunities and challenges that these presented. Moreover, students liked this innovative way of learning and ended with a positive attitude towards ICT. Originality/value Although several courses prepare students to be digital citizens or use ICT to enhance the teaching-learning process, millennials are ill prepared to use cutting-edge technologies in an innovative, responsible and critical way in their future professions. The course that was designed is original in that it goes beyond preparing digital citizens to prepare professionals in any domain to use ICT in an informed and responsible way. Moreover, it is a documented, successful example of an undergraduate universal course in a highly important current society dimension. The authors believe that its pedagogical proposal could be transferred to courses dealing with other global issues such as the environment, economy and peace.

Incompressible smoothed particle hydrodynamics for MHD double-diffusive natural convection of a nanofluid in a cavity containing an oscillating pipe

2019 ◽  
Vol 30 (2) ◽  
pp. 882-917 ◽  
Author(s):  
Abdelraheem M. Aly
Keyword(s):  
Natural Convection ◽  
Smoothed Particle Hydrodynamics ◽  
Cavity Wall ◽  
Lagrangian Description ◽  
Content Type ◽  
Wide Range ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Incompressible Smoothed Particle Hydrodynamics ◽  
Double Diffusive

Purpose This paper aims to adopt incompressible smoothed particle hydrodynamics (ISPH) method to simulate MHD double-diffusive natural convection in a cavity containing an oscillating pipe and filled with nanofluid. Design/methodology/approach The Lagrangian description of the governing partial differential equations are solved numerically using improved ISPH method. The inner oscillating pipe is divided into two different pipes as an open and a closed pipe. The sidewalls of the cavity are cooled with a lower concentration C_c and the horizontal walls are adiabatic. The inner pipe is heated with higher concentration C_h. The analysis has been conducted for the two different cases of inner oscillating pipes under the effects of wide range of governing parameters. Findings It is found that a suitable oscillating pipe makes a well convective transport inside a cavity. Presence of the oscillating pipe has effects on the heat and mass transfer and fluid intensity inside a cavity. Hartman parameter suppresses the velocity and weakens the maximum values of the stream function. An increase on Hartman, Lewis and solid volume fraction parameters leads to an increase on average Nusselt number on an oscillating pipe and left cavity wall. Average Sherwood number on an oscillating pipe and left cavity wall decreases as Hartman parameter increases. Originality/value The main objective of this work is to study the MHD double-diffusive natural convection of a nanofluid in a square cavity containing an oscillating pipe using improved ISPH method.

Numerical investigation of anguilliform locomotion by the SPH method

2019 ◽  
Vol 30 (1) ◽  
pp. 328-346 ◽  
Author(s):  
Amin Rahmat ◽  
Hossein Nasiri ◽  
Marjan Goodarzi ◽  
Ehsan Heidaryan
Keyword(s):  
Drag Coefficient ◽  
Numerical Investigation ◽  
Sph Method ◽  
Content Type ◽  
Aquatic Locomotion ◽  
Wide Range ◽  
Particle Hydrodynamics ◽  
Dummy Particles ◽  
Smoothed Particle ◽  
Sph Algorithm

Purpose This paper aims to introduce a numerical investigation of aquatic locomotion using the smoothed particle hydrodynamics (SPH) method. Design/methodology/approach To model this problem, a simple improved SPH algorithm is presented that can handle complex geometries using updatable dummy particles. The computational code is validated by solving the flow over a two-dimensional cylinder and comparing its drag coefficient for two different Reynolds numbers with those in the literature. Findings Additionally, the drag coefficient and vortices created behind the aquatic swimmer are quantitatively and qualitatively compared with available credential data. Afterward, the flow over an aquatic swimmer is simulated for a wide range of Reynolds and Strouhal numbers, as well as for the amplitude envelope. Moreover, comprehensive discussions on drag coefficient and vorticity patterns behind the aquatic are made. Originality/value It is found that by increasing both Reynolds and Strouhal numbers separately, the anguilliform motion approaches the self-propulsion condition; however, the vortices show different pattern with these increments.

Encouraging millennials to collaborate and learn on the job

2015 ◽  
Vol 14 (4) ◽  
pp. 118-123 ◽  
Author(s):  
Lauren Trees
Keyword(s):  
Knowledge Management ◽  
Best Practices ◽  
Social Networking ◽  
Age Groups ◽  
Lessons Learned ◽  
Retention Rates ◽  
Direct Access ◽  
Content Type ◽  
Business Outcomes ◽  
Wide Range

Purpose – The purpose of this paper is to present enterprise social networking and gamification as two potential tools to help organizations engage Millennial employees in collaboration and learning. Design/methodology/approach – The research provides general descriptions of enterprise social networking and gamification approaches, shares data on adoption of these approaches from APQC’s “2015 Knowledge Management Priorities Data Report” (based on a January 2015 survey of 524 knowledge management professionals) and includes four company examples adapted from APQC’s Connecting People to Content and Transferring and Applying Critical Knowledge best practices studies. The methodology for APQC’s best practices studies involves screening 50 or more organizations with potential best practices in a given research scope area and identifying five or six with proven best practices. APQC then conducts detailed site visits with the selected organizations and publishes case studies based on those site visits. Findings – Enterprise social networking platforms are in place at 50 per cent of organizations, with another 25 per cent planning to implement them by the end of 2015. By providing near-immediate access to information and answers, enterprise social networking helps Millennials learn the ropes at their new workplaces, gives them direct access to more knowledgeable colleagues who can assist and mentor them, and helps them improve their business outcomes by reusing knowledge and lessons learned across projects. Younger workers can also harness the power of social networking to create a sense of belonging and build their reputations in large, dispersed firms, where it is particularly difficult for them to gain visibility. A recent APQC survey indicates that 54 per cent of organizations either currently employ gamification to encourage collaboration or expect to implement it within the next three years. The rush to gamify the enterprise is, at least in part, a reflection of employers’ desire to satisfy Millennials and make them feel connected to a community of co-workers. Although games appeal to a wide range of age groups, Millennials grew up with digital interaction and tend to prefer environments that emphasize teamwork, social learning and frequent feedback – all of which can be delivered through gamification. Originality/value – The value of this paper is to introduce the value of and relationship between enterprise social networking and gamification platforms to human resource (HR) professionals looking to increase engagement and retention rates for Millennial employees.

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