Relevant bibliographies by topics / Friction power losses

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'Friction power losses'

Author: Grafiati
Published: 4 June 2021
Last updated: 16 February 2022

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Journal articles on the topic "Friction power losses"

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Allmaier, H., D. E. Sander, and F. M. Reich. "Simulating Friction Power Losses in Automotive Journal Bearings." Procedia Engineering 68 (2013): 49–55. http://dx.doi.org/10.1016/j.proeng.2013.12.146.

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Zhang, Sheng-Peng, and Tae-Oh Tak. "Efficiency Estimation of Roller Chain Power Transmission System." Applied Sciences 10, no. 21 (October 31, 2020): 7729. http://dx.doi.org/10.3390/app10217729.

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In the present study, a novel approach to estimating the efficiency of roller chain power transmission systems is proposed based on sliding friction losses and damping force. The dynamics model is taken into account between chain links with lateral offset owing to the derailleur system. Frictional losses were calculated according to Coulomb’s law of friction, and the damping force was dependent on the damping coefficient. The effects of rotational speed, load, derailleur system, and damping coefficient on transmission efficiency were analyzed. The test stand of the roller chain power transmission system was set up to verify the estimated efficiency, and the results showed a good correlation, demonstrating the validity of the chain power transmission efficiency estimation.
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Delprete, Cristiana, and Abbas Razavykia. "Piston ring–liner lubrication and tribological performance evaluation: A review." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 232, no. 2 (April 25, 2017): 193–209. http://dx.doi.org/10.1177/1350650117706269.

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Internal combustion engines are at present used as the major power sources for transportation and power generator. Improvement of the internal combustion engine efficiency is expected due to strict environmental standards and energy costs. Any reduction in oil consumption, friction power losses and emissions results in improving engines’ performance and durability. Automotive industries have intense passion to increase engines’ efficiency to meet the fuel economy and emission standards. Many studies have been conducted to develop reliable approaches and models to understand the lubrication mechanisms and calculate power losses. This review paper summarizes the synthesis of the main technical aspects considered during modeling of piston ring–liner lubrication and friction losses investigations. The literature review highlights the effects of piston ring dynamics, components geometry, lubricant rheology, surface topography and adopted approaches, on frictional losses contributed by the piston ring-pack.
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Xu, H., and A. Kahraman. "Prediction of friction-related power losses of hypoid gear pairs." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 221, no. 3 (September 1, 2007): 387–400. http://dx.doi.org/10.1243/14644193jmbd48.

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A model to predict friction-related mechanical efficiency losses of hypoid gear pairs is proposed in this study. The model includes a gear contact model, a friction prediction model, and a mechanical efficiency formulation. The friction model uses a friction coefficient formula obtained by applying multiple linear regression analysis to a large number of elastohydrodynamic lubrication analyses covering typical ranges of key parameters associated with surface roughness, geometry, load, kinematics, and the lubricant. Formulations regarding the kinematic and geometric properties of the hypoid gear contact are presented. The load and friction coefficient distribution predictions are used to compute instantaneous torque/power losses and the mechanical efficiency of a hypoid gear pair at any given position. Results of a parametric study are presented at the end to highlight the influence of key operating conditions, surface finish, and lubricant properties on mechanical efficiency losses of hypoid gears.
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Menacer, Brahim, and Mostefa Bouchetara. "Parametric Analysis of the Effect of Engine Speed and Load on the Hydrodynamic Performance of the Lubricant in Diesel Engine." Periodica Polytechnica Mechanical Engineering 64, no. 4 (September 17, 2020): 299–306. http://dx.doi.org/10.3311/ppme.15725.

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The oil consumption in an internal combustion engine is an important source of pollution and particulate emissions, main efforts are done by the manufacturers to reduce to the maximum the impact of the oil consumption on the emissions of the engine, and to satisfy the increasingly rigorous standards of pollution. The losses by friction due to piston ring friction explain 20 % of the total mechanical losses in internal combustion engines. A reduction in piston ring friction would therefore result in higher efficiency, lower fuel consumption and reduced emissions. The goal of this study is to develop a numerical method by using of GT-Suite software to analyze the influence of engine speed and engine load during the working cycle on oil film thickness, frictional force, power losses. Our predicted results were validated with the experimental data of a previous study, and they have shown a good agreement. The results in the current analysis demonstrated that the engine speed and load have a remarkable effect on oil film thickness, friction force and friction power losses between the top ring and cylinder liner. So, it would help in reducing friction as well as making a contribution towards the improvement of engine performance such as torque, efficiency and fuel consumption.
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Fernandes, Carlos M. C. G., Pedro M. T. Marques, Ramiro C. Martins, and Jorge H. O. Seabra. "Gearbox power loss. Part II: Friction losses in gears." Tribology International 88 (August 2015): 309–16. http://dx.doi.org/10.1016/j.triboint.2014.12.004.

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Wang, Cheng, Huan Yong Cui, Qing Ping Zhang, and Wen Ming Wang. "An approach of calculation on sliding friction power losses in involute helical gears with modification." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 9 (February 22, 2015): 1521–31. http://dx.doi.org/10.1177/0954406215573977.

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Sliding friction between the teeth is recognized as one of the main reasons of power losses in transmission as well as a potential reason of vibration and noise. A new approach is proposed to accurately calculate the sliding friction power losses in involute helical gears considered modification and geometric deviations resulting from the manufacturing processes, assembly errors, and deflections of support structures based on the simulation of gear mesh under light and significant load. Firstly, the paths of contact points on the pinion tooth surface are obtained from tooth contact analysis. Tooth surface load distributions and loaded transmission errors in one mesh period are obtained from loaded tooth contact analysis. Secondly, tooth surface load distributions are converted into the normal forces of tooth surface points of contact, loaded transmission errors are brought to the calculation formulas of sliding velocity, and the sliding friction coefficients of tooth surface points of contact are calculated by a non-Newtonian thermal elastohydrodynamic lubrication model. Substituting the sliding velocities, the normal forces, and the sliding friction coefficients into the power calculation formulas gives the sliding friction power losses of tooth surface points of contact. By the soft MATLAB, the values of the sliding friction power losses are integrated and the sliding friction power loss in helical gears from engagement to disengagement is obtained. Finally, an example of this approach is shown in the end. The results indicate that it is very necessary to consider the influence of loaded transmission errors for calculation of sliding friction power losses.
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Menacer, Brahim, and Mostefa Bouchetara. "The compression ring profile influence on hydrodynamic performance of the lubricant in diesel engine." Advances in Mechanical Engineering 12, no. 6 (June 2020): 168781402093084. http://dx.doi.org/10.1177/1687814020930845.

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For different operating conditions of an internal combustion engine, the piston–ring–liner compartment represents one of the largest sources of friction and power losses. The aim of this article is to evaluate the effect of the compression ring profile on the main tribological performance of the lubricant in a four-stroke diesel engine. A one-dimensional analysis was developed for the hydrodynamic lubrication between the compression piston ring and the cylinder wall. A numerical method was applied to analyze the influence of different ring geometrical designs during the working cycle on oil film thickness, frictional force, and power losses. Our predicted results were validated with the Takiguchi data of a previous study, and they have shown a good agreement. The results in the current analysis demonstrated that the ring geometry profile, the engine speed, and load have a remarkable effect on oil film thickness, friction force, and friction power losses between the top ring and cylinder liner. Therefore, it would help in reducing friction as well as making a contribution to the improvement of engine performance such as torque, efficiency, and fuel consumption.
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Diez-Ibarbia, A., A. Fernandez-del-Rincon, A. de-Juan, M. Iglesias, P. Garcia, and F. Viadero. "Frictional power losses on spur gears with tip reliefs. The friction coefficient role." Mechanism and Machine Theory 121 (March 2018): 15–27. http://dx.doi.org/10.1016/j.mechmachtheory.2017.10.003.

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Jiang, Shuyun, and Yujiang Qiu. "Reducing friction power losses of flywheel energy storage systems using PTFE composites: A technical note." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, no. 10 (March 13, 2019): 1616–21. http://dx.doi.org/10.1177/1350650119836817.

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This technical note aims to reduce friction power loss of flywheel energy storage system (FESS) supported by hydrodynamic spiral groove bearing and permanent magnetic bearing (PMB). An approach is proposed to fabricate the spiral groove bearing using polytetrafluoroethylene (PTFE) composite. A test rig is developed to test tribological properties of the spiral groove PTFE bearings. Also, two PTFE composites (C-PTFE: 80 vol.% PTFE filled with 20 vol.% graphite; C-Cu-PTFE 50 vol.% PTFE filled with 20 vol.% graphite and 30 vol.% copper powder) are tested. Results show that the friction power losses of the C-PTFE and C-Cu-PTFE bearings are lower than that of the traditional albronze (CuAl) bearing in the whole speed range. In addition, the spiral groove PTFE bearings show an excellent friction-reducing property under boundary or mixed lubrication condition. Finally, a case study is given to show the spiral groove PTFE bearing is capable of reducing the friction power loss of the FESS.
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Dissertations / Theses on the topic "Friction power losses"

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TU, MINGHUI. "Validation and modeling of power losses of NJ406 cylindrical roller bearings." Thesis, KTH, Maskinkonstruktion (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193590.

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I de flesta maskiner används lager för att ta upp krafter från roterande komponenter. I en växellåda används lager för att ge axlarna möjlighet att rotera fritt och att begränsa deras rörlighet i axiell och radiell led. För att öka växellådors prestanda är det viktigt att minimera effektförluster och att ha en hög tillförlitliglitlighet. Effektförluster orsakade av lager kan vara betydande i växellådor. Att kunnaprediktera effektförlusterna i lager mera exakt kan ge en bättre översikt av fördelningen av effektförluster i växellådor och för att förbättra deras prestanda. rullager. Huvudsyftet med det här projektet är att ta fram en friktionsmodell för NJ 406 cylindriska rullager. Experiment utfördes i en omgjord kugghjulsrigg, där parametrar som varvtal, last och oljenivåer varierades. Baserat på resultat från de utförda experimenten, jämfördes de med tre redan framtagna lagermodeller från Palmgren, Harris och SKF. Den huvudsakliga forskningsfrågan separerades i fyra delfrågor där analys och jämförelse gjordes mellan de existerande modellerna och utförda experiment. De fyra delfrågorna som undersöktes var; lastoberoende friktionsförluster, lastberoende friktionsförluster, mätosäkerhet och modellering. Oljenivåns, oljetypens, oljetemperaturens, varvtalets och lastens inverkan på lagrens friktionsrespons undersöktes också. Resultaten från mätosäkerhetsanalysen visar att experimenten i det här projektet är repeterbara och att det är möjligt att utveckla nya lagermodeller genom att använda resultaten från de utförda experimenten. Baserat på mätresultaten, passar de lastoberoende friktionsförlusterna från Harris modell bäst. En ny modell för lastberoende förluster utvecklades eftersom ingen av de tre existerande modellerande passar mätresultaten. Därför utvecklades en ny modell som kombinerar Harris modell för lastoberoende lagerförluster och en ny modell lastberoende friktionsförluster.
In most of machines, rotating parts are supported by many types of bearings which may have different requirements. In a gearbox, bearings are normally used to support gear shafts which allow the shafts to rotate freely and limit the axial and radial motion of the shafts. For improving of gearbox performance, it is important to minimize power losses and have high reliability. Power losses caused by bearings can be significant in gearbox system. To be able to predict bearing power losses accurately can give a better overview of the distribution of power losses in the system and is helpful for improving of gearbox performance. The main purpose of this project is to develop an accurate NJ 406 cylindrical roller bearing friction torque model. Numerous experiments were performed on a bearing test rig modified from a back-to-back gear test rig under different conditions, such as different rotating speeds, different loads, different oil level, etc. Based on the results from the experiments, analysis of three existing models, Palmgren, Harris and SKF, were performed. By separating the main research question into four sub research questions, the analysis and comparing between existing models and experimental data were also separated into load independent friction torque analysis, load dependent friction torque analysis, precision analysis and modeling. The influences of oil level, oil type, oil temperature, rotating speed and load on bearing friction torque were also studied. The results of precision analysis show the results of experiments in this project are repeatable and it is able to develop new bearing models by using these experimental results. Based on the experimental data, after modified, the load independent friction torque from Harris model fits the experimental data well. A new model of load dependent bearing friction torque was developed since none of the three existing models fit the experimental data. Therefore, a new NJ 406 cylindrical roller bearing friction torque model was developed which is modified Harris model for load independent friction torque and the new model for load dependent friction torque.
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Šedo, Matej. "Ztráty ve valivých ložiscích." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231815.

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Subject of this thesis is analysis of friction power losses in rolling bearings and design and implementation of computing program. Thesis is divided into six chapters. At the beginning there is overview of different types of rolling bearings and their system of lubrication. Fundamentals of elastohydrodynamic lubrication are described together with effects that occur in lubricant. Remaining part is focused on friction in rolling bearing its sources and calculation. Other programs for computing friction losses are shown and own program is designed. Designed program is applied on bearings of chosen type and results are compared with existing models.
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Wheeler, Jean-David. "Non-elliptical point contacts : The Torus-on-Plane conjunction." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI131/document.

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Cette thèse est dédiée à l’étude des contacts lubrifiés tore-plan sous diverses conditions. Ces contacts se situent à l’interface entre l’extrémité torique des rouleaux et le collet de la bague dans les roulements à rouleaux. La première complexité de cette étude provient de la géométrie particulière des solides concernés. La deuxième est générée par la cinématique complexe qui règne dans ces contacts. Afin de comprendre les mécanismes physiques à l’œuvre, une approche duale (expérimentale et numérique) est adoptée. Le banc d’essai Jérotrib permet une première étude basée sur l’hypothèse que le contact élastohydrodynamique tore-plan est similaire à un contact elliptique équivalent. Grâce à une méthode d’interférométrie optique en lumière blanche qui a été adaptée aux spécificités du contact en question, des mesures précises de l’épaisseur de film ont été effectuées dans un nombre significatif de conditions. Sur cette base, un modèle numérique thermo-élastohydrodynamique a été validé avec précision. Ce dernier a permis d’étudier les écoulements de fluide à l’entrée du contact afin de mettre en évidence leur influence sur le champ d’épaisseur de film. Le modèle numérique a ensuite été amélioré afin de prendre en compte la vraie forme des solides. Il a été validé en épaisseur de film par le banc d’essai Tribogyr, dans des conditions similaires à celles rencontrées dans les vrais roulements. Il a été montré que le cisaillement du fluide est responsable de l’échauffement des solides, qui diminue par suite l’épaisseur de film : ceci souligne la nécessité de modéliser cet échauffement global pour prédire la séparation des surfaces. Par ailleurs, lors de l’étude, le champ de pression et d’épaisseur de film ont perdu leurs symétries à cause de la cinématique et de la forme des solides. Toutefois, le comportement du contact est resté similaire à celui d’un contact elliptique, en dehors de certains cas limites
This thesis is dedicated to the study of torus on plane contacts under various operating conditions. They can be found at the interface between the torus roller-end and the flange in roller bearings. The first challenge of this thesis is to deal with unusual mating geometries. The other challenge is the presence of a complex kinematic which operates in these contacts. In order to further develop the understanding of such a contact, a dual approach (experimental and numerical) is adopted. The Jérotrib test-rig enables a first study, by considering that the élastohydrodynamic torus on plane contact can be modelled by an elliptical equivalent contact. Thanks to a differential colorimetric interferometry method which was improved and adapted during the thesis, precise film thickness measurements are carried out under a rather wide range of operating conditions. A thermo-elastohydrodynamic numerical model is developed and validated by comparing its results to the ones of the test-rig. A numerical study on film forming is then proposed and the role of the contact ellipticity is investigated. The numerical model is improved in order to take into account the actual shape of the solids. A film thickness validation of the model is proposed, thanks to measurements performed on the Tribogyr test-rig. The operating conditions are very similar to the one encountered in actual bearings, and the mating solids have representative geometries: it is an actual torus-on-plane contact. It is demonstrated that the lubricant shearing is responsible for the solids temperature rise, which in its turn, reduces the film thickness. It appears mandatory to be able to predict this global warming of the bodies. It is also demonstrated that the pressure and film thickness distributions lose their symmetry because of the spinning kinematic and the solids shape. However, the behaviour of the torus-on-plane contact appears very similar to the one of an elliptical equivalent contact, apart from some limit cases
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Xu, Hai. "Development of a generalized mechanical efficiency prediction methodology for gear pairs." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1128372109.

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Zhu, Yi, Lei Zhou, Lei Zhang, Cong Zhao, Zimu Wang, and Huayong Yang. "Assessment of friction loss to horizontally built fluid passages using additive manufacturing." Technische Universität Dresden, 2020. https://tud.qucosa.de/id/qucosa%3A71081.

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Selective laser melting (SLM), is a type of additive manufacturing, which selectively melts a pre-spread layer of metal powders and produce a part by a layer-on-layer manner. SLM has demonstrated a great potential to reduce size and weight in hydraulic manifolds. However, a theoretical base is lacking since friction loss is unclear in a SLMed fluid passage. In this study, various fluid passages without supports, from diameters from 4 mm to 16 mm, were produced horizontally using SLM. The profile was measured using a 3D scanner and surface roughness was measured using a confocal laser scanning microscope. Friction factor was studied using simulation, experiments, and classical theory. The hydraulic diameter of the SLMed passages is smaller than the design diameter. Surface roughness is extremely high on the top part of the inner wall while the rest part is around 10 μm. Such trends are irrelevant of passage diameters. Friction factors in SLMed passage is much larger than those predicted using Moody theory, particularly in laminar flow. The transition from laminar flow to turbulent flow appears at a smaller Reynolds number with increased passage diameter. The influence of the profile overweighs that of the surface roughness on friction factor.
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Sawadkosin, Paranee. "Optimalizace tvaru strojních součástí s vlivem variabililty vstupních údajů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401572.

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The objective of this Master’s thesis is to find shape optimal design based on min- imizing friction force of thrust bearing by using genetic algorithm(GA) which is one of an optimization toolbox in Matlab. Reducing the friction force of thrust bearing is one way of making shaft to decreasing friction losses. With four parameters of thrust bearing geometry number of segments(m), angle of running surface(), segment inner radius(R0), and segment outer radius(R1) substitute in Reynolds’ equation. In order to know friction force, it is necessary to generate a connecting variable, oil film thickness(h0) from loading capacity(W ) and revolution per minute(rpm). Friction power loss, as well as weight func- tion conclude the final shape optimization of thrust bearing: m = 7, = 0.1, R0 = 15 mm, and R1 = 20 mm.
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Book chapters on the topic "Friction power losses"

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Zhang, Zh. "Power Loss Due to Bearing Frictions." In Pelton Turbines, 203–5. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-31909-4_14.

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Hammami, Maroua, Olfa Ksentini, Nabih Feki, Mohamed Slim Abbes, and Mohamed Haddar. "Comparative Study Between Experimental and Theoretical Frictional Power Losses of a Geared System." In Applied Condition Monitoring, 21–30. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-85584-0_3.

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"Kinematic Speeds, Friction Torque, and Power Loss." In Essential Concepts of Bearing Technology, 199–212. CRC Press, 2006. http://dx.doi.org/10.1201/9781420006599-13.

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"Kinematic Speeds, Friction Torque, and Power Loss." In Rolling Bearing Analysis - 2 Volume Set, 570–83. CRC Press, 2006. http://dx.doi.org/10.1201/9781482275148-32.

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Zhou, Q., I. Shilling, and S. H. Richardson. "Prediction of total engine friction power loss from detailed component models." In Tribology Series, 761–66. Elsevier, 2003. http://dx.doi.org/10.1016/s0167-8922(03)80189-x.

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Yan, Xiao, Jinguang Zang, Ting Xiong, Xi Sui, Yanping Huang, and Zejun Xiao. "The Basic Thermal Hydraulic Issues of Applying Supercritical Fluid to Nuclear Reactors." In Advanced Applications of Supercritical Fluids in Energy Systems, 481–553. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-2047-4.ch015.

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This chapter is mainly focused on illustrating some introductory progress on thermal hydraulic issues of supercritical water, including heat transfer characteristics, pressure loss characteristics, flow stability issues and numerical method. These works are mainly performed in Nuclear Power Institute of China (NPIC) these years, to give a basic idea of elementary but important topics in this area. An analytical method was proposed up to predict the heat transfer coefficient and friction coefficient based on the two-layer wall function. Flow instability experiments have been carried out in a two-parallel-channel system with supercritical water, aiming to provide an up-to-date knowledge of supercritical flow instability phenomena and initial validation data for numerical analysis. An in-house code has been developed in NPIC in order to better utilize and further expand the experimental results on supercritical flow instability. At last, some future research directions are suggested for reference.
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Matsumoto, S., and K. Morikawa. "The new estimation formula of coefficient of friction in rolling-sliding contact surface under mixed lubrication condition for the power loss reduction of power transmission gears." In International Gear Conference 2014: 26th–28th August 2014, Lyon, 1078–88. Elsevier, 2014. http://dx.doi.org/10.1533/9781782421955.1078.

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Conference papers on the topic "Friction power losses"

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Ren, Wei-Min. "Windage and Axial Friction Losses of High Speed Generator." In International Joint Power Generation Conference collocated with TurboExpo 2003. ASMEDC, 2003. http://dx.doi.org/10.1115/ijpgc2003-40078.

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Air-cooled generators have been fulfilling a wide range of applications recently. Concurrent with a low cost target, the market demands high efficiency and high performance designs. Windage and friction losses, caused by rotor rotation and cooling gas flowing through the ventilation circuits, represents one of the largest loss components in air-cooled generators. Carefully managing the windage and friction loss is critical to ensure the success of air-cooled generators. This work is motivated by development of air-cooled high-speed generators. In such applications, the flow inside the annular gap between the rotor and stator is highly turbulent. The flow characteristics are not fully understood. Physics-based correlations, which calculate the windage and friction losses, don’t exist in the literature. The purpose of this work is to develop such transfer functions for machine design. Numerical simulations, using commercial CFD code FLUENT 6.0 and Design of Experiment (DOE) method, have been carried out to study the flow characteristics in the annular space between the cylindrical rotor and stator. All simulations were performed using an axial-symmetric model, along with RNG k-ε turbulence model and enhanced wall treatment. In the study, the generator rated speed ranged from 5000 to 20000 rpm; the Taylor number ranged from 1750 to 78000; and the Mach number ranged from 0.25 to 1.0. The effect of axial flow on windage loss was carefully studied. Axial flow exhibited a strong impact on windage loss. The CFD results are rationalized. Transfer functions for windage and axial friction losses are created. They provide a better basis to explore the design space at the early stage of the product development.
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Moslatt, Geir-Arne, and Michael R. Hansen. "Modeling of Friction Losses in Offshore Knuckle Boom Crane Winch System." In 2018 Global Fluid Power Society PhD Symposium (GFPS). IEEE, 2018. http://dx.doi.org/10.1109/gfps.2018.8472316.

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Heingartner, Petra, and David Mba. "Determining Power Losses in Helical Gear Mesh: Case Study." In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/ptg-48118.

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Currently legislation is in place to encourage a reduction in energy usage. As such there is an increased demand for machinery with higher efficiencies, not only to reduce the operational costs of the machinery, but also to cut capital expenditure. The power losses associated with the gear mesh can be divided into speed and load dependant losses. This paper reviews some of the mathematical models proposed for the individual components associated with these losses, such as windage, churning, sliding and rolling friction loses. A mathematical model is proposed which predicts the power losses on helical gears highlighting the major contributor to losses in the gear mesh. Furthermore, the mathematical model is validated with a case study.
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Payri, Francisco, Jose R. Serrano, Pablo Olmeda, Arlington Paez, and Fabrice Vidal. "Experimental Methodology to Characterize Mechanical Losses in Small Turbochargers." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22815.

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Turbocharging and turbocharger phenomena have been studied by many authors covering a wide range of subjects. One of these subjects, and objective of this work, is mechanical losses due to friction. Current work presents a methodology to characterize mechanical losses in small size turbochargers. Such methodology is based on low and constant operating temperature values for the turbine, lubricating oil, and compressor. In this way, a quasi-adiabatic operation of the turbocharger is achieved which allows separating friction power from heat transfer. The experiments performed have covered variations in turbocharger speed, lubricating oil pressure and temperature. Heat flows between turbine and compressor has been maintained as reduced as possible by means of the experiment conditions. The results obtained show satisfactory correlation between mechanical efficiency of the studied turbocharger and non-dimensional magnitudes.
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Morgenstern, Roman, Wolfgang Kießling, and Simon Reichstein. "Reduced Friction Losses and Wear by DLC Coating of Piston Pins." In ASME 2008 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/ices2008-1650.

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A Diamond Like Carbon (DLC) coating is well known to offer superior wear and friction behaviour. This combination of properties makes DLC suitable for many different areas of tribology. This paper concerns itself with usage in the power cylinder environment of automotive diesel engines. To estimate the potential of DLC coatings applied to piston pins in internal combustion engines, linearly reciprocating sliding wear examinations have been performed on uncoated and DLC coated component segments versus different counterpart materials as present in the power cylinder environment, including: piston (aluminium alloy), bushing (brass), piston pin (steel) and connecting rod (steel). Evaluation criteria for the tests include friction and wear performance in dry and lubricated conditions. Test results show how the DLC coatings offer impressive wear reductions for each of the different counterpart materials used. Furthermore, special emphasis is given to the analysis of the friction behaviour. As expected, the coefficient of friction (COF) decreased for aluminium and steel counterparts when the piston pin segments were DLC coated. However, for the combination of DLC with brass the COF increased in the dry condition. This surprising outcome is explained with SEM and EDX investigations of the wear traces. The tests at elevated temperature with lubrication show an inverse relationship with respect to friction criteria when compared with the dry room temperature tests for the DLC with brass combination. Examined engine tests confirm the results of the non-engine wear test rig, showing that DLC coatings applied on piston pins also exhibit properties and good potential to decrease frictional losses and fuel consumption in modern engines.
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Wienecke, Dirk, and Wilfried J. Bartz. "Influence of Base Oil and Formulation of Gear Oils on Friction Power Losses of Gears." In International Fuels & Lubricants Meeting & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1999. http://dx.doi.org/10.4271/1999-01-3465.

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7

"Contribution to the study of power losses due to friction phenomenon between spur gear teeth." In 1st International Symposium on Dielectric Materials and Applications. Materials Research Forum LLC, 2016. http://dx.doi.org/10.21741/9781945291197-16.

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Irimescu, Luminita, Emanuel Diaconescu, and Yves Berthier. "A New Point of View on Rolling Friction Coefficient." In ASME/STLE 2004 International Joint Tribology Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/trib2004-64381.

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The micro-slip developed in contact area points is involved in rolling friction. It occurs in some points whilst in others the surfaces move together. Contact area is divided into micro-slip zones, subjected to opposite shear stresses. These are computed in each point and their values yield the power lost by interface friction and related micro-slip torque. Theoretical results are checked by comparison with published data. The specific power loss, defined as the power lost by friction on a unity of contact area, does not depend on direction of shear and its integral over contact area yields the lost power due to micro-slip. The micro-slip component of rolling friction coefficient is calculated by dividing power losses by the product between normal load and relative angular velocity. Global rolling friction coefficient includes as well hysteresis losses. Experimental evidences confirm well the advanced model.
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Hetmanczyk, Janusz, Krzysztof Krykowski, Zbigniew Galuszkiewicz, and Patryk Galuszkiewicz. "Air friction losses in PM BLDC motor with external rotor operating as kinetic energy storage system." In 2021 IEEE 19th International Power Electronics and Motion Control Conference (PEMC). IEEE, 2021. http://dx.doi.org/10.1109/pemc48073.2021.9432552.

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Lamquin, Thierry, and Kostandin Gjika. "Power Losses Identification on Turbocharger Hydrodynamic Bearing Systems: Test and Prediction." In ASME Turbo Expo 2009: Power for Land, Sea, and Air. ASMEDC, 2009. http://dx.doi.org/10.1115/gt2009-59599.

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Design of automotive engines, with increasing focus on downsizing, high performance and low fuel emissions, provides several challenges to turbocharging technology and design. The development of a low friction rotor-bearing system is fundamental to effectively differentiate in the current environment. The exhaust gas energy from the turbine is transmitted through the bearing system to the compressor stage, and then to the engine. A lower bearing system friction allows more power to be transmitted to the compressor. This paper deals with experimental and analytical investigations for rotor-bearing system (RBS) power losses. A powerful test facility and associated experimental approach, based on the temperature drop of the gas flowing through the turbine stage, have been developed. The uncertainty due to instrumentation and process is identified as lower than 12%. The power loss related to the radial bearing is calculated analytically using the laminar Couette model; the power loss due to the axial bearing is calculated by the integration of the 2D Reynolds equation. The additional power loss between the slender shaft and inner bearing surface is calculated using a turbulent Couette model. The power loss due to the seals is not taken into account. Extensive testing in steady state condition has been completed on the test bench. Two different bearing designs with axial grooves have been tested. The influence of oil on the bearing loss has been identified by testing at two oil inlet temperatures (30 °C and 100 °C) and two oil inlet pressures (2 bars and 4 bars). The measurement and prediction of power losses are in good agreement.
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