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Статті в журналах з теми "Chambres des vannes"
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Meshalkin, Valery P., Nicolay A. Martsulevich, Oleg M. Flisyuk, Ilia G. Likhachev, and Antony M. Nzioka. "Hydrodynamics of Energy-Efficient Axial-Flow Cyclones for Environmentally Safe Cleaning of Gas and Dust Emissions." Energies 16, no. 2 (January 10, 2023): 816. http://dx.doi.org/10.3390/en16020816.
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We investigated the operation of an axial-flow cyclone as the most promising dust-cleaning equipment based on energy consumption. Numerical solutions were obtained for the gas-solids suspension flow equations in axial flow cyclones with different separation chambers’ geometry using FlowVision software. The chamber’s geometrical features determined the nature of the gas-solids suspension flow, directly affecting the dusty gases’ purification degree. The circulating gas flows and the turbulent “trace” after the swirl generator were found to negatively influence the cyclone efficiency and the hydraulic resistance values. A high chamber height also negatively affected the gas purification since the bulk of dust particles were removed from the gas-solids flow at the initial section. The initial section’s length coincided with the gas-solids suspension’s jet flow zone due to the flow coming off the swirl vanes’ edges. Due to turbulent mixing, the particles’ secondary entrainment and return to the gas flow began to manifest outside this zone. Based on this analysis, it is possible to develop recommendations for choosing the chamber’s geometric parameters, minimizing the influence of the indicated factors. On the basis of this research, it will be possible to ensure cyclones’ high efficiency with significantly lower hydraulic resistance when designing axial-flow cyclones relative to other types of cyclone.
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Han, Fenghui, Zhe Wang, Yijun Mao, Jiajian Tan, and Wenhua Li. "Flow Control of Radial Inlet Chamber and Downstream Effects on a Centrifugal Compressor Stage." Applied Sciences 11, no. 5 (March 1, 2021): 2168. http://dx.doi.org/10.3390/app11052168.
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Radial inlet chambers are widely used in various multistage centrifugal compressors, although they induce extra flow loss and inlet distortions. In this paper, the detailed flow characteristics inside the radial inlet chamber of an industrial centrifugal compressor have been numerically investigated for flow control and performance improvement. First, the numerical results are validated against the experimental data, and flow conditions inside the inlet chambers with different structures are compared. They indicate that, in the non-guide vane scheme, sudden expansions, tangential flows and flow separations in the spiral and annular convergent channels are the major causes of flow loss and distortions, while using guide vanes could introduce additional flow impacts, separations and wakes. Based on the flow analysis, structure improvements have been carried out on the radial inlet chamber, and an average increase of 4.97% has been achieved in the inlet chamber efficiencies over different operating conditions. However, the results further reveal that the increases in the performance and overall flow uniformity just in the radial inlet chamber do not necessarily mean a performance improvement in the downstream components, and the distribution of the positive tangential velocity at the impeller inlet might be a more essential factor for the efficiency of the whole compressor.
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Mevissen, Frank, and Michele Meo. "A Review of NDT/Structural Health Monitoring Techniques for Hot Gas Components in Gas Turbines." Sensors 19, no. 3 (February 9, 2019): 711. http://dx.doi.org/10.3390/s19030711.
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The need for non-destructive testing/structural health monitoring (SHM) is becoming increasingly important for gas turbine manufacturers. Incipient cracks have to be detected before catastrophic events occur. With respect to condition-based maintenance, the complex and expensive parts should be used as long as their performance or integrity is not compromised. In this study, the main failure modes of turbines are reported. In particular, we focus on the turbine blades, turbine vanes and the transition ducts of the combustion chambers. The existing monitoring techniques for these components, with their own particular advantages and disadvantages, are summarised in this review. In addition to the vibrational approach, tip timing technology is the most used technique for blade monitoring. Several sensor types are appropriate for the extreme conditions in a gas turbine, but besides tip timing, other technologies are also very promising for future NDT/SHM applications. For static parts, like turbine vanes and the transition ducts of the combustion chambers, different monitoring possibilities are identified and discussed.
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Han, Fenghui, Zhe Wang, Yijun Mao, Jiajian Tan, and Wenhua Li. "Experimental and numerical studies on the influence of inlet guide vanes of centrifugal compressor on the flow field characteristics of inlet chamber." Advances in Mechanical Engineering 12, no. 11 (November 2020): 168781402097490. http://dx.doi.org/10.1177/1687814020974909.
Повний текст джерелаАнотація:
Inlet chambers (IC) are the typical upstream component of centrifugal compressors, and inlet guide vanes in the IC have a great impact on its internal flow and aerodynamic loss, which will significantly influence the performance of the downstream compressor stages. In this paper, an experimental study was carried out on the flow characteristics inside a radial IC of an industrial centrifugal compressor, including five testing sections and 968 measuring points for two schemes with and without guide vanes. Detailed distributions of flow parameters on each section were obtained as well as the overall performance of the radial IC, and the causes of the flow loss inside the IC and the non-uniformity of flow parameters at the outlet section were investigated. Besides, numerical simulations were performed to further analyze the flow characteristics inside the radial IC. The experimental and numerical results indicate that, in the scheme without guide vanes, sudden expansions in the spiral channel and flow separations in the annular convergence channel are the major sources of flow loss and distortions generated in the radial IC; while in the scheme with guide vanes, the flow impacts, separations and wakes caused by the inappropriate design of guide vanes are the main reasons for the flow loss of the IC itself and the uneven flow distributions at the IC outlet.
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Shaikh, Faisal, and Budimir Rosic. "Unsteady phenomena at the combustor-turbine interface." Journal of the Global Power and Propulsion Society 5 (November 23, 2021): 202–15. http://dx.doi.org/10.33737/jgpps/143042.
Повний текст джерелаАнотація:
The combustor-turbine interface in a gas turbine is characterised by complex, highly unsteady flows. In a combined experimental and large eddy simulation (LES) study including realistic combustor geometry, the standard model of secondary flows in the nozzle guide vanes (NGV) is found to be oversimplified. A swirl core is created in the combustion chamber which convects into the first vane passages. Four main consequences of this are identified: variation in vane loading; unsteady heat transfer on vane surfaces; unsteadiness at the leading edge horseshoe vortex, and variation in the position of the passage vortex. These phenomena occur at relatively low frequencies, from 50–300 Hz. It seems likely that these unsteady phenomena result in non-optimal film cooling, and that by reducing unsteadiness designs with greater cooling efficiency could be achieved. Measurements were performed in a high speed test facility modelling a large industrial gas turbine with can combustors, including nozzle guide vanes and combustion chambers. Vane surfaces and endwalls of a nozzle guide vane were instrumented with 384 high speed thin film heat flux gauges, to measure unsteady heat transfer. The high resolution of measurements was such to allow direct visualisation in time of large scale turbulent structures over the endwalls and vane surfaces. A matching LES simulation was carried out in a domain matching experimental conditions including upstream swirl generators and transition duct. Data reduction allowed time-varying LES data to be recorded for several cycles of the unsteady phenomena observed. The combination of LES and experimental data allows physical explanation and visualisation of flow events.
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Sadykova, Samal, Abay Dostiyarov, Mikhail Zhumagulov, and Nurlan Kartjanov. "The influence of turbulence on the efficiency and reliability of combustion chamber of the gas turbine." Thermal Science, no. 00 (2021): 64. http://dx.doi.org/10.2298/tsci200831064s.
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The article presents the research results related to the influence of turbulence on the efficiency of the combustion chamber of gas turbine. An artificial increase in the intensity of turbulence is considered as a way to improve the formation of a fuel-air mixture. Turbulent flow is formed due to the installation of guide swirlers at the entrance to the device for creating a fuel-air mixture - a micro module. The angle of rotation of the swirler blades is selected. Theoretical research, mathematical software modeling, as well as an aerodynamic experiment have been carried out. As a result, design solutions are provided that significantly increase the efficiency and reliability of the gas turbine combustion chamber. In the course of the study, guide vanes were selected, and their design was established. The recommended swing angle of the swirler guide vanes is 40?. The recommended depth of the fuel injector inside the chamber is 1.0 gauge.
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Zhang, Huiyan, Fan Meng, Lei Cao, Yanjun Li, and Xinkun Wang. "The Influence of a Pumping Chamber on Hydraulic Losses in a Mixed-Flow Pump." Processes 10, no. 2 (February 19, 2022): 407. http://dx.doi.org/10.3390/pr10020407.
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In this study, entropy generation theory based on computational fluid dynamics (CFD) is used to study the influence of a pumping chamber type (guide vane and volute scheme) on the spatial distribution of hydraulic loss in a mixed-flow pump. The CFD data of the mixed-flow pump with a volute is validated by external characteristic test data under Q = 561.4–1598.6 m3/h. The results show that the efficiency and the head of the guide vanes scheme are lower under Q = 800–1200 m3/h, which resulted from a higher total entropy production (TEP) in the pumping chamber and outlet pipe. The high total entropy production rate (TEPR) inside the guide vanes can be found near the leading edge of the hub side and trailing edge of the rim side due to flow separation, which reduces the recovery efficiency of kinetic energy of the guide vanes. The high TEPR inside outlet pipe can be seen near the inlet, caused by back flow. However, the efficiency and head of the volute scheme are lower, under Q = 1200–1600 m3/h, owing to the fact that the volute cannot effectively convert kinetic energy into pressure energy and thus the high TEPR can be found near outlet of volute and inlet of outlet pipe. These results can provide useful suggestions to the matching optimization of the impeller and pumping chamber in a mixed-flow pump.
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Kotlov, Andrey, Leonid Kuznetsov, and Boris Hrustalev. "Investigation of the influence of the number of vanes on the performance of a rotary vane compressor." MATEC Web of Conferences 245 (2018): 04008. http://dx.doi.org/10.1051/matecconf/201824504008.
Повний текст джерелаАнотація:
We developed a mathematical model for determining the parameters of mass transfer in the compressor chambers during the processes of compression and discharge. The mass flow rates through the end and radial gaps were determined. Also we analyzed the processes of mass transfer in a clamped volume. We investigated the influence of the number of vanes on the compressor efficiency, taking into account changes in the compressor geometric parameters. We established that overflows through the end surfaces of rotor mainly affect the compressor performance. In order to reduce overflows during the period of discharge, it was proposed to increase the angle of closure of the discharge window at a fixed angle of its opening. The mathematical model allows one to make recommendations on the choice of the optimal number of vanes for a particular design.
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Povarova, K. B., and O. A. Skachkov. "Preparation, Structure, and Properties of Ni3Al and NiAl Light Powder Alloys for Aerospace." Materials Science Forum 534-536 (January 2007): 1585–88. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.1585.
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New light super-heat-resistant powder Ni3Al and NiAl-based alloys (of the Ni-Al-Mo-B, Ni-Al-Fe-La, and Ni-Al-Y2O3 systems), as well as a new technology for preparing and processing them have been developed. The density of the alloys was 7.3-7.5 and ~6 g/cm 3, respectively. The Ni3Al sheets were used to prepare shields for combustion chambers in gas-turbine engines by roomtemperature deformation; the shields are intended for the long-term operation at 1100-1200°C and for the short-term use at 1300°C. The activated NiAl powders alloyed with Fe+La were used to produce sintered complex-shape articles, such as combustion stabilizers in a jet unit of combustion chamber of the gas-turbine installation, heat sources, etc. capable of operating at t≤1500°C under low mechanical stresses. At 1100, 1300, and 1500°C, the 100-h strength of the heat-resistant NiAl- (2-7.5) vol. % Y2O3 alloys subjected to directional recrystallization is 70, 35 and ≥10 MPa, respectively. The vanes, in which the length of recrystallized grain is smaller than the vane length by a factor of 1.5-2, were manufactured from these alloys.
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Bao, Ming, and Jiming Lin. "Numerical simulation of combustion distribution in a gas burner." E3S Web of Conferences 236 (2021): 01002. http://dx.doi.org/10.1051/e3sconf/202123601002.
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The combustion effect of natural gas-air mixed combustion is optimised through an effective and rational design of the burner structure, thereby reducing the emission of atmospheric pollutants and achieving energy saving and emission reduction. This paper starts from the geometric model of the burner and uses Computational Fluid Dynamics (CFD) technology to numerically simulate the combustion distribution in the burner, which results in the combustion distribution of the burner after optimising the structure. The guiding effect of the blower guide vanes on the airflow is weak, and the back pressure effect of the guide vanes mounting body is significant, which reduces the primary air volume and prolongs the combustion history in the central region of the flame; The temperature field is evenly distributed and the combustion is well distributed; CH4 and CO in the furnace chamber are basically burned out and the NO concentration in the furnace chamber is about 800 ppm, which basically meets the emission standard and the combustion effect is good. This paper has certain guiding significance for the study of burner structure.
Дисертації з теми "Chambres des vannes"
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Bertholds, Alexander. "CFD Simulations of the New University of Sydney Boundary Layer Wind Tunnel." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-166945.
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Using Computational Fluid Dynamics Simulations, the flow in the new University of Sydney closed circuit wind tunnel has been analyzed prior to the construction of the tunnel. The objective was to obtain a uniform flow in the test section of the wind tunnel while keeping the pressure losses over the tunnel as low as possible. This was achieved by using several flow-improving components such as guide vanes, screens, a honeycomb and a settling chamber. The guide vanes were used in the corners and in the diverging part leading into the settling chamber, giving a significant improvement of the flow as they prevent it from taking undesired paths. The settling chamber is used to decelerate the flow before it is accelerated when leaving the settling chamber, a process which reduces the turbulence in the flow. Screens were used in the settling chamber to further improve the flow by imposing a pressure drop which evens out differences in the flow speed and reduces the turbulence. The honeycomb, which is situated in the end of the settling chamber, makes the flow more uniform by forcing it to go in only one direction. A uniform flow was obtained using three screens and one honeycomb together with the guide vanes and the settling chamber.
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Rubensdörffer, Frank G. "Numerical and Experimental Investigations of Design Parameters Defining Gas Turbine Nozzle Guide Vane Endwall Heat Transfer." Doctoral thesis, KTH, Energiteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3884.
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The primary requirements for a modern industrial gas turbine consist of a continuous trend of an increasing efficiency combined with very low emissions in a robust, cost-effective manner. To fulfil these tasks a high turbine inlet temperature together with advanced dry low NOX combustion chambers are employed. These dry low NOX combustion chambers generate a rather flat temperature profile compared to previous generation gas turbines, which have a rather parabolic temperature profile before the nozzle guide vane. This means that the nozzle guide vane endwall heat load for modern gas turbines is much higher compared to previous generation gas turbines. Therefore the prediction of the nozzle guide vane flow field and endwall heat transfer is crucial for the engineering task of the design layout of the vane endwall cooling system. The present study is directed towards establishing new in-depth aerodynamic and endwall heat transfer knowledge for an advanced nozzle guide vane of a modern industrial gas turbine. To reach this objective the physical processes and effects which cause the different flow fields and the endwall heat transfer pattern in a baseline configuration, a combustion chamber variant, a heat shield variant without and with additional cooling air and a cavity variant without and with additional cooling air have been investigated. The variants, which differ from the simplified baseline configuration, apply design elements which are commonly used in real modern gas turbines. This research area is crucial for the nozzle guide vane endwall heat transfer, especially for the advanced design of the nozzle guide vane of a modern industrial gas turbine and has so far hardly been investigated in the open literature. For the experimental aerodynamic and endwall heat transfer research of the baseline configuration of the advanced nozzle guide vane geometry a new low pressure, low temperature test facility has been developed, designed and constructed, since no experimental heat transfer data exist in the open literature for this type of vane configuration. The new test rig consists of a linear cascade with the baseline configuration of the advanced nozzle guide vane geometry with four upscaled airfoils and three flow passages. For the aerodynamic tests the two middle airfoils and the hub and the tip endwall are instrumented with pressure taps to monitor the Mach number distribution. For the heat transfer tests the temperature distribution on the hub endwall is measured via thermography. The analysis of these measurements, including comparisons to research in the open literature shows that the new test rig generates accurate and reproducible results which give confidence that it is a reliable tool for the experimental aerodynamic and heat transfer research on the advanced nozzle guide vane of a modern industrial gas turbine. Previous own research work together with the numerical analysis performed in another part of the project as well as conclusions from a detailed literature study lead to the conclusion that advanced Navier-Stokes CFD tools with the v2-f turbulence model are most suitable for the calculation of the flow field and the endwall heat transfer of turbine vanes and blades. Therefore this numerical tool, validated against different vane and blade geometries and for different flow conditions, has been chosen for the numerical aerodynamic and endwall heat transfer research of the advanced nozzle guide vane of a modern industrial gas turbine. The evaluation of the numerical and experimental investigations of the baseline configuration of the advanced design of a nozzle guide vane shows the flow field of an advanced mid-loaded airfoil design with the features to reduce total airfoil losses. For the hub endwall of the baseline configuration of the advanced design of a nozzle guide vane the flow characteristics and heat transfer features of the classical vane endwall secondary flow model can be detected with a very weak intensity and geometric extension compared to the studies of less advanced vane geometries in the open literature. A detailed analysis of the numerical simulations and the experimental data showed very good qualitative and quantitative agreement for the three-dimensional flow field and the endwall heat transfer. These findings, together with the evaluations obtained from the open literature, lead to the conclusions that selected CFD software Fluent together with the applied v2-f turbulence model exhibits a high level of general applicability and is not tuned to a special vane or blade geometry. Therefore the CFD code Fluent with the v2-f turbulence model has been selected for the research of the influence of the several geometric variants of the baseline configuration on the flow field and the hub endwall heat transfer of the advanced nozzle guide vane of a modern industrial gas turbine. Most of the vane endwall heat transfer research in the open literature has been carried out only for baseline configurations of the flow path between combustion chamber and nozzle guide vane. Such a simplified geometry consists of a long, planar undisturbed approach length upstream of the nozzle guide vane. The design of real modern industrial gas turbines however requires often significant variations from this baseline configuration consisting of air-cooled heat shields and purged cavities between the combustion chamber and the nozzle guide vane. A detailed evaluation of the flow field and the endwall heat transfer shows major differences between the baseline and the heat shield configuration. The heat shield in front of the airfoil of the nozzle guide vane influences the secondary flow field and the endwall heat transfer pattern strongly. Additional cooling air, released under the heat shield has a distinctive influence as well. Also the cavity between the combustion chamber and the nozzle guide vane affects the secondary flow field and the endwall heat transfer pattern. Here the influence of additional cavity cooling air is more decisive. The results of the detailed studies of the geometric variants are applied to formulate guidelines for an optimized design of the flow path between the combustion chamber and the nozzle guide vane and the nozzle guide vane endwall cooling configuration of next-generation industrial gas turbines.QC 20100917
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Chun-YiTseng and 曾俊怡. "Rotary-Vane Air Machines Having Noncircular Chamber Profiles." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/45964540043299643141.
Повний текст джерелаАнотація:
碩士國立成功大學
機械工程學系
102
This research presents the analysis and design of rotary-vane air motors having noncircular chamber profiles. Air motors produce very high specific power. They require compressed air rather than electricity; thus avoid sparks and can be used in demanding environments. Same as other types of rotary machines, air motors exhibit torque fluctuations. The varying torque curve is a result of unmatched torques generated by the vanes in one revolution. Torque fluctuations produce dynamic speed ripples that further introduce undesirable vibration. Rather than using auxiliary flywheels to smoothen the fluctuation, we use a new stator configuration that can help produce a nearly constant output torque. Meanwhile, the rotary-vane air motors can be more efficient by setting a reasonably higher expansion ratio for stator profile. A simulation model using FLUENT is also established to validate the result of analytical model. To validate the present designs, a new air motor is illustrated to show the speed ripples can be successfully reduced, while the efficiency can be increased. This research also presents the application of noncircular profile design in the field of air compressors, expect that the peak of driving torque can be reduced by using noncircular chamber profiles. Through this research, the noncircular profile design is expected to reduce energy wasting and costs.
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(6331784), Ryan P. Jenkins. "An Analysis of a Pressure Compensated Control System of an Automotive Vane Pump." Thesis, 2019.
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Pressure compensated vane pump systems are an attractive solution in many automotive applications to supply hydraulic power required for cooling, lubrication, and actuation of control elements such as transmission clutches. These systems feature variable displacement vane pumps which offer reductions in parasitic loads on the engine and in wasted hydraulic energy at high engine speeds when compared to traditional fixed displacement supply pumps. However, oscillations in a currently available pressure compensation system limits the achievable performance and therefore the application of this solution.
This dissertation presents the development and experimental validation of a lumped parameter model in MATLAB/Simulink of a current pressure compensated vane pump system for an automatic transmission oil supply application. An analysis of the performance of this system using the validated pump model and a developed black box control system model reveals that the low cost solenoid valve present in the control circuit to set the regulation pressure limits the achievable bandwidth to 1.84Hz and causes a significant time delay in the response. To address this limitation, as well as eliminate a non-minimum phase zero introduced by the case study’s control circuit architecture, an actively controlled electrohydraulic pressure compensation system is proposed. This proposed system is explored both experimentally and in simulation making use of the accuracy of the presented variable displacement vane pump model. Significant improvements in the achievable system performance are shown with both a simple PI control law (47% reduction in the pressure response time) and an advanced cascaded model following controller based on feedback linearization (58% reduction in the pressure response time). An analysis of these results reveals that implementing the proposed control system with a 5(L/min)/bar proportional valve with a 20Hz at ±100% (60Hz at ±50%) amplitude bandwidth and a PI control law is an economical path to achieving the best performance improvements for this automotive application.
Книги з теми "Chambres des vannes"
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J, Maffeo Robert, Schwartz S, and United States. National Aeronautics and Space Administration., eds. Engine structures analysis software: Component specific modeling (COSMO). [Washington, D.C.]: National Aeronautics and Space Administration, 1994.
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Mendelsohn, John. The Einsatzgruppen or murder commandos. Clark, NJ: Lawbook Exchange, 2009.
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Mendelsohn, John. The Einsatzgruppen or murder commandos. Clark, NJ: Lawbook Exchange, 2009.
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Traub, Hartmut. Ein Stolperstein für Benjamin: Den namenlosen Opfern der NS-"Euthanasie". Essen: Klartext, 2013.
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Hinton, Alexander Laban. Aesthetics (Theary Seng, Vann Nath, and Victim Participation). Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198820949.003.0007.
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The second part of the book, “Turbulence,” centers on the transitional justice encounter of three survivors (Theary Seng, Vann Nath, and Bou Meng) involved in victim participation at the Extraordinary Chambers in the Courts of Cambodia (ECCC). Chapter 4, for example, is loosely structured around the idea of aesthetics and the experience of two victims who participated in the proceedings, Theary Seng and former S-21 prisoner Vann Nath. If the 2008 reenactment highlighted the performative dimensions of the transitional justice imaginary, it also suggested an implicit aesthetics as a former prison that had been converted into a genocide museum was, in this moment, envisioned as a crime site now inhabited by court personnel, victims and witnesses, and defendant, and evidence. The ECCC has a similar aesthetics of justice, ranging from court regalia and symbols to courtroom demeanor, technologies, styles of speech and movement, and public participation. The first part of the chapter centers on the experience of the first civil party, Theary Seng. Originally skeptical of the ECCC, Seng came to believe it had transformative possibilities in terms of promoting democracy in Cambodia. To this end, in a series of pretrial hearings, she sought to speak directly in court. Initially successful, Seng was eventually silenced as the Pre-Trial Chamber ruled that civil parties could only speak through their lawyers. Seng, for her part, became increasingly critical of the court, stating that she refused to be a piece of “décor” in a “sham.” Eventually she would renounce her civil party status and become an outspoken critic of the court, which was increasingly beset by controversy. The remainder of the chapter focuses on Vann Nath’s Case 001 testimony. On the day of his testimony, the 500-seat courtroom was packed, as it would be during many subsequent trial sessions. Vann Nath’s art, much of which he had produced during People’s Republic of Kampuchea for display at Tuol Sleng, was reintroduced as juridical evidence and shown in court. The chapter explores some of these aesthetic dimensions of the transitional justice imaginary even as it considers the lived experience and practices that informed Vann Nath’s art, including Buddhist aesthetics and beliefs.
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The Einsatzgruppen or murder commandos. Clark, NJ: Lawbook Exchange, 2009.
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The Einsatzgruppen or murder commandos. Clark, NJ: Lawbook Exchange, 2010.
Знайти повний текст джерелаТези доповідей конференцій з теми "Chambres des vannes"
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Lin, D. G., and B. P. Huynh. "Effects of Guide Vanes in Transition Flow From a Round Pipe to a Rectangular Chamber." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65640.
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In an effort to design a rectangular-box chamber for model testing and flow visualization, to be fitted into an existing horizontal axial-flow pump circuit, shown in Fig.1[1], a computational study has been conducted into the flow of water as it expands from a 400-mm-diameter round pipe into a 3-D-rectangular-box configuration. The geometry is asymmetric; the chamber’s bottom is aligned with the pipe’s bottom, but the pipe’s top is expanded into the chamber’s top, shown in Fig. 2. A commercial Computational Fluid Dynamics (CFD) software package is used to simulate the isothermal turbulent flow, using the standard K-epsilon turbulence model. The study examines the benefits of the guide vane in reducing the transition region’s length and producing the desirable flow pattern in the test chamber.
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Koupper, Charlie, Guillaume Bonneau, Laurent Gicquel, and Florent Duchaine. "Large Eddy Simulations of the Combustor Turbine Interface: Study of the Potential and Clocking Effects." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-56443.
Повний текст джерелаАнотація:
With the generalization of Lean Burn combustors, the flow field entering the turbine tends to feature higher levels of swirl, turbulence, while different hot streak patterns often emerge if compared to the previous generation of combustion chambers. In this context, the combustor-turbine interactions and more specifically the transport of hot streaks through the turbine need to be further analysed to gain engine performance and improved turbine life. Considering this new context, a non-reactive axial combustor simulator representative of a Lean Burn architecture, together with a 1.5 high pressure turbine stage is developed within the European project FACTOR. The interaction between these two modules is numerically investigated by performing Large Eddy Simulation (LES) of the combustor simulator equipped with two Nozzle Guide Vanes (NGVs). By using such an integrated approach, the combustor-turbine interface (plane 40) disappears, allowing: (i) more realistic inlet conditions to the turbine by suppressing all the assumptions associated with averaged profiles; (ii) to account for the potential effect of the vanes on the chamber. Note that if compared to classical approaches, the use of time-resolved LES has the advantage of well predicting the combustor mean flow and turbulence, resulting in more realistic flow properties at the turbine inlet as confirmed by previous works on this configuration. This paper focuses first on two LESs of the combustor-turbine specific configurations: i.e., two clocking positions of the hot streak relative to the NGVs. Significant changes on the thermal field around the vanes are highlighted. When the hot streak is injected in front of a vane leading edge, it considerably heats up the pressure side compared to the adjacent vane although the temperature field is quite uniform at the NGV exit because of the enhanced mixing of the hot streak. On the other hand, when the hot streak is injected in the passage between two adjacent vanes, it remains away from the vane walls preventing them from heating up. The hot streak however crosses the vane passage without being significantly distorted resulting in a more heterogeneous flow field at the rotor inlet. Second, the potential effect induced by the presence of the vanes is investigated by comparing the flow field inside the chamber with and without NGVs. It is found that the potential effect does not alter temperature patterns while a significant radial and azimuthal mass flow redistribution is observed up to about 25% axial chord length upstream of the vanes. The turbulence level is affected by the presence of vanes up to plane 40 when the hot streak is aligned with the passage.
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Frosina, Emma, Adolfo Senatore, Dario Buono, Kim A. Stelson, Feng Wang, and Haiyang Gao. "A Three-Dimensional CFD Methodology to Study Vane-Ring and Vane-Under-Vane Interactions of a Vane Pump Power Split Transmission." In 9th FPNI Ph.D. Symposium on Fluid Power. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fpni2016-1568.
Повний текст джерелаАнотація:
This paper presents a study of a novel vane pump power split transmission (VPPST). The transmission incorporates a new component, the Vane Power Split Unit (VPSU). The VPSU is a double-acting vane pump with a floating ring where the input shaft is connected to the engine and the floating ring is connected to the output shaft. The VPSU generates hydraulic oil flow at a rate proportional to the difference in angular velocities between the input and output shafts. This flow enters a hydraulic motor mounted to the output shaft. The vane pump power split transmission (VPPST) is a combination of the double-acting vane pump (VPSU) and the hydraulic motor directly connected to the pump. A CFD model of the VPSU has been created to better understand its performance. The model uses the three-dimensional CFD commercial code PumpLinx®, developed by Simerics® Inc. Thanks to collaboration with the code developers, the model is able to predict the complex fluid dynamics in the pockets in the rotor into which the vanes retract. These pockets are referred to as under-vane volumes. The rotor of the vane pump, in fact, has several internal channels that connect the pumping chambers between the vanes to the under-vane volumes. The combination of the vanes and the internal ducts and volumes of the under-vanes have been modelled as dynamic “valves” that rotate with the rotor. In this way the radial movements of the vanes are computed as a part of the simulation, based on the pressures due to the compression of the volumes on the inner diameter side of the vanes. The study is a result of collaboration between the University of Minnesota and the University of Naples “Federico II” research groups and the code developers of Simerics® Inc. The universities and Simerics® Inc. have all been involved in this project, working in close cooperation for the model building and simulations.
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Xue, Haokun, and Mehdi Esmaeilpour. "Renewable Energy Production by Solar Chimney: The Influence of Curved Guide Vanes on the Performance of a Solar Chimney Using CFD Simulation." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-71491.
Повний текст джерелаАнотація:
Abstract This study uses Computational Fluid Dynamics (CFD) to investigate the effect of guide vanes on power output of turbine installed in a solar chimney. A full scale three-dimensional CFD simulation of solar chimney power plant based on Manzanares prototype is performed to simulate the air flow inside the solar chimney. First, the flow field is simulated in presence of guide vanes with no turbine inside the chimney. Three guide vanes with different tip angles of 30°, 60° and 90° are considered. It is observed that the presence of guide vanes significantly affects the flow direction and the heat stored inside the blade chamber. Moreover, the change in output power of solar chimney under different turbine rotational velocities and different guide vanes is studied. A twelve-blade turbine is placed right above the exit of the guide vanes at the start of chimney. Various cases including three angles, 30°, 60°, and 90° guide vanes, and three rotational velocities, 40, 80, and 120 rpm are run to find output power. The Multiple Reference Frame (MRF) method is used to treat the rotation of the turbine. The analysis of power output of the turbine shows that the maximum power of 82.2 kW is reached by the case of 30° guide vane at 80 rpm. Comparing to the power of the 90° guide vane at the same rotational velocity, which is 66.3 kW, the increase is about 23.9%.
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Zubrilin, Roman A., Ivan A. Zubrilin, Sergey S. Matveev, and Sergey G. Matveev. "Gaseous Fuel Flame Stabilization in a Modular Swirled Burner." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57441.
Повний текст джерелаАнотація:
Stable combustion is one of the main requirements for combustion chambers of gas turbine engines. Therefore, the prediction of combustor stable operation limits during the design stage is an important task. The stable operation limits with a sufficient degree of accuracy can be determined by experiments or using computational fluid dynamics. The present paper describes a numerical and experimental investigation of swirled premixed flame stabilization in a modular swirled burner (MSB). The burner has a vane swirler and a diffuser with a cylindrical tube downstream of the swirler. This design has several advantages. First, the cylindrical tube protects the flame from external disturbances and acts as the pre-chamber in which combustion efficiency can reach high values. Secondly, the swirled flow of the fresh mixture passes along the walls of the tube and prevents them from overheating. The influence of the swirler vanes angle on MSB lean blow out (LBO) was experimentally and numerically investigated. The results of the experiments were also used to validate the simulation results. All studies were conducted under atmospheric conditions in an open-space laboratory environment. Three-dimensional modeling was carried out using the large eddy simulation (LES) with a Smagorinsky–Lilly subgrid model. Combustion was described within the Flamelet Generated Manifold model. Initially, the influence of the size and shape of outlet boundary, the mesh resolution and turbulent-chemistry interaction models was investigated. As a result the configuration of the model was received, which allows simulating LBO with sufficient accuracy. Stable operation limits for several types of MSB geometries and different fuels (methane and propane) were subsequently established. It was found that in the case of swirler vane angle equal to 45 degrees the range of stable operation limits is wider than in the case of 60 degrees. The influence of pre-chamber length on LBO was studied only numerically. It was discovered that with increasing pre-chamber length, the LBO limits become wider, but the possibility of the tube walls overheating becomes higher too.
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Du, Haifen, Danmei Xie, Wei Chen, Ziyue Mei, and Jing Zhang. "Overall Cooling Effectiveness on a Gas Turbine Vane With Swirl-Film Cooling." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91103.
Повний текст джерелаАнотація:
Abstract Numerical calculation of conjugate heat transfer is carried out to study the effect of combined film and swirl cooling at the leading edge of a gas turbine vane with a a cooling chamber inside, in which 3-D steady RANS approach with the k-ω SST turbulence model is used. Two different kinds of coolant chamber configuration (C1 and C2) are selected. In C2, the cooling chamber is composed of a front cavity and a back cavity, and the two cavities are connected by a passage which is divided into 16 segments. The comparative investigations between C1 and C2 cases have been carried out to study the effect of different cooling chambers at M = 0.25, 0.5, 1 and 2. For two cases, overall cooling effectiveness increases with M increasing. In C1 case, with increasing M, differences of mass flow through film holes rows will decrease. The variation of mass flow from holes changes by less than 26.7% at M = 2. However, in C2 case, mass flow through S1 and S2 is significantly larger than that through other film holes rows. Area-averaged overall effectiveness in C2 is larger by 2.5% at M = 0.25 compared to C1 case.
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Bommarito, Gregory E., and Roger Fales. "Design Optimization and Efficiency Modeling of a Hot Gas Vane Motor." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43405.
Повний текст джерелаАнотація:
The purpose of this work is to model and analyze the dynamics of a hot gas vane motor for later design optimization work. The pneumatic motor is a portable direct drive actuator that is intended as an alternative to battery-powered electromagnetic motors. It is believed that the vane motor could eventually replace other solution for portable power generation. An optimal design of the motor is desirable to maximize portability and efficiency. Modeling the device will make it possible to optimize the mechanical efficiency by altering the geometry of the motor’s vanes and respective chambers. While the efficiency of the motor is affected to a great extent by its geometry, losses from leakage and friction will also be considered. For the device to remain portable, there are limitations on the size of the final design which will restrict the optimal efficiency of the vane motor.
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Rundo, Massimo, and Giorgio Altare. "Lumped Parameter and Three-Dimensional CFD Simulation of a Variable Displacement Vane Pump for Engine Lubrication." In ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69124.
Повний текст джерелаАнотація:
The paper describes the modelling and the experimental tests of a variable displacement vane pump for engine lubrication. The approach used for the simulation has involved 3D commercial tools for tuning a 0D customized model implemented in the LMS Amesim® environment. Different leakage paths are considered and the axial clearances are variable to take into account the deformation of the pump cover, calculated through a finite element analysis with ANSYS®. The vane tip clearances are calculated as function of the dynamic equilibrium equation of the vanes. The displacement control takes into account the internal forces on the stator due to the pressure in all variable chambers and to the contact force exerted by the vanes. The discharge coefficients in the resistive components have been tuned by means of a complete 3D transient model of the pump built with PumpLinx®. The tuned 0D model has been proved to be reliable for the determination of the steady-state flow-speed and flow-pressure curves, with a correct estimation of the internal leakages and of the pressure imposed by the displacement control. The pump has been also tested using a simplified circuit and a fair agreement has been found in the evaluation of the delivery pressure ripple.
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Bari, S., and Idris Saad. "Improvements of Performance and Emissions of a Diesel-Gen-Set With Biodiesel Having Guide Vanes of Various Angles." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65994.
Повний текст джерелаАнотація:
Biodiesel has physiochemical properties similar to diesel fuel and it is renewable. It can be used in diesel engines with no or minor modifications. If biodiesel can be produced from renewable sources such as vegetable or other sources, the CO2 emission produced from the engine running on biodiesel can be consumed by the source itself. Then, the net production of CO2 emission in the atmosphere will be zero. However, the viscosity and density of biodiesel are higher than diesel fuel. These inferior properties make biodiesel less prone to evaporate, diffuse and mix with in-cylinder air resulting in inferior combustion and lower engine performance than diesel fuel. If the in-cylinder air-turbulence inside the combustion chamber can be increased, then this will probably enhance the higher viscous and lesser volatile biodiesel to evaporate faster and mix with air better resulting in better performance. Therefore, in this research, guide vanes were installed into the intake runner to increase the in-cylinder air turbulence especially during the injection period. Five guide vanes with the angles of 25°, 30°, 35°, 40° and 45° were fabricated and tested. The vanes were tested on a diesel-gen-set and run with 100% biodiesel. Based on the experimental results, the vane angle of 35° was found to be optimum as this vane angle showed the highest reductions of break specific consumption, CO and HC by 1.77%, 8.78% and 7.5%, respectively compared to the run with biodiesel without vanes. The other vanes showed lower improvements. Therefore, this research concludes that the improvement of in-cylinder air-turbulence can enhance the engine performance with higher viscous biodiesel.
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Bacci, Tommaso, Gianluca Caciolli, Bruno Facchini, Lorenzo Tarchi, Charlie Koupper, and Jean-Louis Champion. "Flowfield and Temperature Profiles Measurements on a Combustor Simulator Dedicated to Hot Streaks Generation." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-42217.
Повний текст джерелаАнотація:
In order to deepen the knowledge of the interaction between modern lean burn combustors and high pressure turbines, a real scale annular three sector combustor simulator has been assembled at University of Florence, with the goal of investigating and characterizing the generated aerothermal field and the hot streaks transport between combustor exit and the high pressure vanes location. To generate hot streaks and simulate lean burn combustors behavior, the rig is equipped with axial swirlers, fed by main air flow that is heated up to 531 K, and liners with effusion cooling holes that are fed by air at ambient temperature. The three sector configuration is used to reproduce the periodicity on the central sector and to allow to perform measurements inside the chamber, through the lateral walls. Ducts of different length have been mounted on the swirlers, preserving the hot mainflow from the interaction with coolant. Such configurations, together with the one without ducts, have been tested, using different measurement techniques, in order to highlight the differences in the resulting flow fields. First of all, isothermal PIV measurements have been performed on the combustion chamber symmetry plane, to highlight the mixing phenomena between the mainflow and cooling flows. Then a detailed investigation of the mean aerothermal field at combustor exit has been carried out, for nominal operating conditions, by means of a five hole pressure probe provided with a thermocouple, installed on an automatic traverse system. With the aim of analyzing the hot streaks transport and the flow field modification towards the vanes location, such measurements have been performed on two different planes: one located in correspondence of the combustor exit and the further one placed downstream, in the virtual location of the vanes leading edges. Therefore, an experimental database, describing the evolution of the flow field in a combustor simulator with typical traits of modern lean burn chambers, for different injector geometries, has been set up.