Journal articles: '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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Johansson, Staffan, Per H. Nilsson, Robert Ohlsson, and Bengt-Göran Rosén. "A Novel Approach to Reduction of Frictional Losses in a Heavy-Duty Diesel Engine by Reducing the Hydrodynamic Frictional Losses." Advances in Tribology 2017 (2017): 1–17. http://dx.doi.org/10.1155/2017/9240703.

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An important parameter in the reduction of fuel consumption of heavy-duty diesel engines is the Power Cylinder Unit (PCU); the PCU is the single largest contributor to engine frictional losses. Much attention, from both academia and industry, has been paid to reducing the frictional losses of the PCU in the boundary and mixed lubrication regime. However, previous studies have shown that a large portion of frictional losses in the PCU occur in the hydrodynamic lubrication regime. A novel texturing design with large types of surface features was experimentally analyzed using a tribometer setup. The experimental result shows a significant reduction of friction loss for the textured surfaces. Additionally, the textured surface did not exhibit wear. On the contrary, it was shown that the textured surfaces exhibited a smaller amount of abrasive scratches on the plateaus (compared to the reference plateau honed surface) due to entrapment of wear particles within the textures. The decrease in hydrodynamic friction for the textured surfaces relates to the relative increase of oil film thickness within the textures. A tentative example is given which describes a method of decreasing hydrodynamic frictional losses in the full-scale application.

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Polizelli, M. A., F. C. Menegalli, V. R. N. Telis, and J. Telis-Romero. "Friction losses in valves and fittings for power-law fluids." Brazilian Journal of Chemical Engineering 20, no. 4 (October 2003): 455–63. http://dx.doi.org/10.1590/s0104-66322003000400012.

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Diab, Y., F. Ville, and P. Velex. "Prediction of Power Losses Due to Tooth Friction in Gears." Tribology Transactions 49, no. 2 (July 2006): 260–70. http://dx.doi.org/10.1080/05698190600614874.

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Knauder, Christoph, Hannes Allmaier, and David E. Sander. "Sub-assembly Resolved Friction Power Losses of Different Engine Concepts." MTZ worldwide 80, no. 3 (February 8, 2019): 58–63. http://dx.doi.org/10.1007/s38313-018-0151-0.

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Tee, J. W., S. H. Hamdan, and W. W. F. Chong. "Predictive tool for frictional performance of piston ring-pack/liner conjunction." Journal of Mechanical Engineering and Sciences 13, no. 3 (September 27, 2019): 5513–27. http://dx.doi.org/10.15282/jmes.13.3.2019.19.0445.

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Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are derived from Reynolds equation by using Reynolds’ boundary conditions to generate the contact pressure distribution along the complete piston ring-pack/liner conjunction. The predicted minimum film thickness is then used to predict the friction generated between the piston ring-pack and the engine cylinder liner. The engine in-cylinder friction is predicted using Greenwood and Williamson’s rough surface contact model. The model considers both the boundary friction and the viscous friction components. These mathematical models are integrated to simulate the total engine in-cylinder friction originating from the studied piston ring-pack for a complete engine cycle. The predicted minimum film thickness and frictional properties from the current models are shown to correlate reasonably with the published data. Hence, the proposed mathematical approach prepares a simplistic platform in predicting frictional losses of piston ring-pack/liner conjunction, allowing for an improved fundamental understanding of the parasitic losses in an internal combustion engine.

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Sayfidinov, Khaydarali, S. Doruk Cezan, Bilge Baytekin, and H. Tarik Baytekin. "Minimizing friction, wear, and energy losses by eliminating contact charging." Science Advances 4, no. 11 (November 2018): eaau3808. http://dx.doi.org/10.1126/sciadv.aau3808.

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One-fourth of the global energy losses result from friction and wear. Although friction and tribocharging were presented to be mutually related, reduction of friction and wear by eliminating tribocharges on common polymers, and decrease of power losses in devices with polymer parts were not shown to date. Here, we demonstrate that for common polymers, friction—which is strongly related to surface charge density—can be notably reduced by various methods of tribocharge mitigation, namely, corona discharging, solvent treatment, or placing a grounded conductor on the backside of one of the shearing materials. In our simple demonstrations, we found that by preventing tribocharge accumulation, a remarkable two-thirds of power loss during operation of simple mechanical devices with common polymers and plastic parts can be saved and wear can be reduced by a factor of 10. These demonstrations indicate important practical ramifications in mechanical systems with insulating parts.

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Arana, Aitor, Jon Larrañaga, and Ibai Ulacia. "Partial EHL friction coefficient model to predict power losses in cylindrical gears." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 233, no. 2 (June 13, 2018): 303–16. http://dx.doi.org/10.1177/1350650118778655.

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The accurate prediction of friction coefficient and power losses in the gear mesh is a key subject to several gear-related fields of study. However, there is still not a unified method for large ranges of operating conditions, different gear geometries and lubricant types. The current paper meets this demand by modelling partial EHL friction with an asperity-fluid load sharing approach where fluid traction is calculated with the Ree-Eyring equation and the reference stress behaviour is predicted from piezoviscosity coefficient. It will be shown that only an accurate description of the lubricant’s viscosity behaviour is required to compute friction in gears. Finally, mesh power losses are predicted considering thermal effects and numerical predictions are compared to experimental results showing good agreement.

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WASILCZUK, Filip, Michał WASILCZUK, and Michał WODTKE. "HYDROSTATIC THRUST BEARING WITH REDUCED POWER LOSSES." Tribologia 281, no. 5 (November 1, 2018): 123–31. http://dx.doi.org/10.5604/01.3001.0012.7664.

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In many cases in rotating machinery, axial load is carried by tilting pad thrust bearings which have been developed since the beginning of 20th century. For high reliability and simplicity, most commonly the bearings are bath lubricated. In the times of sustainable development, however, minimization of friction losses becomes an important criterion for machinery assessment, and a strategic goal of their development. Performed calculations, based on elementary rules of fluid dynamics, showed that shearing losses in specially designed hydrostatic bearings can be considerably smaller than the losses in tilting pad hydrodynamic bearings. The aim of the research described in this paper was to check if the preliminary results presented earlier and conclusions of benefits of the further increase of the size of the hydrostatic pocket can be confirmed with the use of CFD calculations.

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Joachim, Franz J., Norbert Kurz, and Joerg Börner. "Reduction of Power Losses in Transmissions and Gearings." Applied Mechanics and Materials 86 (August 2011): 883–88. http://dx.doi.org/10.4028/www.scientific.net/amm.86.883.

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In modern motor vehicles, having a driveline that is optimally designed for each vehicle provides a substantial CO2 reduction. Different transmission systems such as, for example, manual transmissions, torque-converter transmissions, dual clutch transmissions and hybrid systems, work better with different requirements and vehicle classes. By increasing the number of gears and the transmission-ratio spread, the engine can run with more fuel efficiency without a loss of driving dynamics. The transmission efficiency itself can be improved by using fuel efficient transmission oil, optimizing the lubrication systems and pumps, improving shifting strategies and optimizing the friction characteristics of gearings, bearings and seals/gaskets [1].

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Ahmed Ali, Mohamed Kamal, Hou Xianjun, Richard Fiifi Turkson, and Muhammad Ezzat. "An analytical study of tribological parameters between piston ring and cylinder liner in internal combustion engines." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 230, no. 4 (August 3, 2016): 329–49. http://dx.doi.org/10.1177/1464419315605922.

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This paper presents a model to study the effect of piston ring dynamics on basic tribological parameters that affect the performance of internal combustion engines by using dynamics analysis software (AVL Excite Designer). The paramount tribological parameters include friction force, frictional power losses, and oil film thickness of piston ring assembly. The piston and rings assembly is one of the highest mechanically loaded components in engines. Relevant literature reports that the piston ring assembly accounts for 40% to 50% of the frictional losses, making it imperative for the piston ring dynamics to be understood thoroughly. This analytical study of the piston ring dynamics describes the significant correlation between the tribological parameters of piston and rings assembly and the performance of engines. The model was able to predict the effects of engine speed and oil viscosity on asperity and hydrodynamic friction forces, power losses, oil film thickness and lube oil consumption. This model of mixed film lubrication of piston rings is based on the hydrodynamic action described by Reynolds equation and dry contact action as described by the Greenwood–Tripp rough surface asperity contact model. The results in the current analysis demonstrated that engine speed and oil viscosity had a remarkable effect on oil film thickness and hydrodynamic friction between the rings and cylinder liner. Hence, the mixed lubrication model, which unifies the lubricant flow under different ring–liner gaps, is needed via the balance between the hydrodynamic and boundary lubrication modes to obtain minimum friction between rings and liner and to ultimately help in improving the performance of engines.

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Statsenko, V., and A. Sukhorada. "Research of Heat Power in Friction Stir Spot Welding." Key Engineering Materials 806 (June 2019): 81–86. http://dx.doi.org/10.4028/www.scientific.net/kem.806.81.

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Nowadays the most perspective, high-tech and productive process is friction stir spot welding. The most important part of this technology is to determine the temperature of the material in the stir zone. This parameter is easily counted by the amount of the heat input, put in the welding zone. We made experimental researches about the relation of the heat power, therotation speed and the diameter of the working tool. For that purpose an experimental scheme was chosen, which models a welding material (aluminum alloy AMg5) as an experimental tube 20 mm in diameter. The tool (shear steel P6M5) is modeled as a working plate. Measurements of the frictional moments depending on the rotation speed of the experimental working tube during the constant temperature are made on the prepared stand. By the experimental data the specific heat input and the heat power were counted on every concentric ring, 2 mm in width, in the end of the working tool, 20 mm in diameter. Also, the sum of the heat power for the whole tool during various rotation speed terms was counted too. On the stand throughout the experiment were determined all the thermal conductivity heat losses along the rod, which the experimental tube was pinned on, all the working plate heat losses through the gasket towards the working desk and the convection from the surface of the rotating experimental tube to the environment. According the data, any of these losses is from 3 to 10 percent. This is shown in the heat input counting.

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Prabhu Sekar, R., V. Edwin Geo, and Leenus Jesu Martin. "A mixed finite element and analytical method to predict load, mechanical power loss and improved efficiency in non-standard spur gear drives." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 231, no. 11 (March 1, 2017): 1408–24. http://dx.doi.org/10.1177/1350650117697594.

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A reasonably accurate estimation of gear power loss is desirable to maximize gear performance. The load share by teeth pair, contact stress, sliding speed, elastohydrodynamic film thickness and coefficient of friction are some of the most important contributing factors which determine frictional power losses in gears. This paper presents an improvement concept to minimize the load-related power losses (sliding and rolling power losses), which will lead to an enhancement in gear efficiency by selection of non-standard gears. The tooth thickness at the pitch circle of the pinion and gear is different in non-standard gears (kpπm > 0.5 πm and kgπm < 0.5 πm), whereas it is equal in standard gears (kpπm = kgπm = 0.5 πm). In this work, the load share-based frictional power loss and the respective mechanical efficiency have been determined for comparative performance of standard and non-standard gears. Finally, the influence of various gear and drive parameters such as gear ratio, pressure angle pinion teeth number and addendum height factor on gear efficiency has also been investigated and the results of the parametric study are discussed.

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Gordon, W. A., C. J. Van Tyne, and S. Sriram. "Extrusion Through Spherical Dies—An Upper Bound Analysis." Journal of Manufacturing Science and Engineering 124, no. 1 (April 1, 2001): 92–97. http://dx.doi.org/10.1115/1.1419198.

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An upper bound solution for extrusion through a spherical die has been developed. Equations for the velocity and strain rate fields in the deformation zone are presented. The equations to determine the internal power of deformation, shear power losses along the two surfaces of velocity discontinuity and friction power losses along the die workpiece interface are shown. In order to maintain generality, these power terms have been calculated via numerical integration methods. The shear power losses and the friction power losses for the extrusion through a spherical die are of similar magnitude as for the extrusion through an “equivalent” conical die. The internal power of deformation is greater for the spherical die as compared to the conical die especially at large radius of curvatures for the spherical die. From the model the optimal die curvature can be determined which minimizes the pressure required to extrude through a spherical die. The analysis presented herein can be generalized to any axisymmetric die shape, which produces a cylindrical product from a cylindrical billet. This extension can be accomplished with minimal changes in the model.

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Richardson, D. E. "Review of Power Cylinder Friction for Diesel Engines." Journal of Engineering for Gas Turbines and Power 122, no. 4 (April 2, 2000): 506–19. http://dx.doi.org/10.1115/1.1290592.

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Power cylinder friction is a major contributor to overall engine friction. For engines of the future to become more fuel efficient it will be necessary to reduce power cylinder friction. To be able to reduce the friction it is important to fully understand it. This paper is a review of power cylinder friction with a specific emphasis on diesel engines. This paper first describes how significant the contribution of power cylinder friction is compared to all the other losses of the engine. It compares the mechanical friction of the engine to the total energy produced by the engine. Then a comparison is made of the power cylinder friction to overall mechanical friction. A comparison of different methods of friction measurement is be made. The advantages and disadvantages are given for each method. There is also a comparison of motoring versus firing friction tests. An equation is given to estimate the effect of bore and stroke on power cylinder friction. Other equations for estimating power cylinder friction are also shown. More sophisticated cylinder kit models are reviewed. Finally a review is made of methods for reducing friction. These are based on a broad review from various companies. [S0742-4795(00)01604-5]

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Shin, Younggy, Sung-Ho Chang, and Sam-Ok Koo. "Performance test and simulation of a reciprocating engine for long endurance miniature unmanned aerial vehicles." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 219, no. 4 (April 1, 2005): 573–81. http://dx.doi.org/10.1243/095440705x11013.

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Development of an engine with good fuel economy is very important for successful implementation of long endurance miniature UAVs (unmanned aerial vehicles). In the study, a four-stroke glow-plug engine was modified to a gasoline-fuelled spark ignition engine. Engine tests measuring performance and friction losses were conducted to tune a simulation program for performance prediction. It has been found that excessive friction losses are caused by insufficient lubrication at high speeds. The simulation program predicts that engine power and fuel economy become worse with high altitude, due to an increasing portion of friction losses. The simulation results suggest quantitative guidelines for further development of a practical engine.

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Leighton, M., Nicholas Morris, Gareth Trimmer, Paul D. King, and Homer Rahnejat. "Efficiency of disengaged wet brake packs." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 6 (March 10, 2018): 1562–69. http://dx.doi.org/10.1177/0954407018758567.

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Key objectives in off-highway vehicular powertrain development are fuel efficiency and environmental protection. As a result, palliative measures are made to reduce parasitic frictional losses while sustaining machine operational performance and reliability. A potential key contributor to the overall power loss is the rotation of disengaged wet multi-plate pack brake friction. Despite the numerous advantages of wet brake pack design, during high-speed manoeuvre in highway travel or at start-up conditions, significant frictional power losses occur. The addition of recessed grooves on the brake friction lining is used to dissipate heat during engagement. These complicate the prediction of performance of the system, particularly when disengaged. To characterise the losses produced by these components, a combined numerical and experimental approach is required. This paper presents a Reynolds-based numerical model including the effect of fluid inertia and squeeze film transience for prediction of performance of wet brake systems. Model predictions are compared with very detailed combined Navier–Stokes and Rayleigh-Plesset fluid dynamics analysis to ascertain its degree of conformity to representative physical operating conditions, as well the use of a developed experimental rig. The combined numerical and experimental approach is used to predict significant losses produced during various operating conditions. It is shown that cavitation becomes significant at low temperatures due to micro-hydrodynamic action, enhanced by high fluid viscosity. The magnitude of the losses for these components under various operating conditions is presented. The combined numerical-experimental study of wet multi-plate brakes of off-highway vehicles with cavitation flow dynamics has not hitherto been reported in the literature.

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Karpenko, M. A., A. A. Glushchenko, and G. V. Karpenko. "Specification of cold running-in quality to power change losses for friction." Vestnik of Ulyanovsk state agricultural academy, no. 2(46) (June 20, 2019): 14–18. http://dx.doi.org/10.18286/1816-4501-2019-2-14-18.

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Gurova, Elena G. "Eddy Current Impact Estimation in Designing Vibroisolator with 3D Electromagnetic Stiffness Compensator." Applied Mechanics and Materials 792 (September 2015): 519–23. http://dx.doi.org/10.4028/www.scientific.net/amm.792.519.

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In this research the method of the calculation of the power losses in DC electromagnet through eddy currents, which are analog of the viscous friction, is presented. The influence of these currents on the operation of the vibroisolator with the electromagnetic stiffness compensator is estimated. The losses of the power on eddy currents are less than 1 per cent of the electromagnet power itself and the compensator totally. The example of the calculation of the losses for eddy currents in steel conductor is also shown.

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Silva, Carlos AF, Lionel Manin, Marie-Ange Andrianoely, Etienne Besnier, and Didier Remond. "Power losses distribution in serpentine belt drive: Modelling and experiments." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 13 (January 25, 2019): 3424–37. http://dx.doi.org/10.1177/0954407018824943.

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Over the last years, significant research effort has been directed towards developing vehicle transmissions more energy efficient. This effort has been a direct consequence of the new environmental regulations encouraging truck and car manufacturers to reduce the power losses of their engines. For development purposes and in belt transmission design, it is worth predicting the power losses before manufacturing. For predicting the power losses in serpentine belt drive, theoretical models have been developed taking into consideration different types of energy loss taking place in a front engine accessory drive. These losses have several origins: from the poly-V belt or the mechanical components of the system (bearings, tensioners). The present paper reviews the state-of-the-art research on power losses modelling in a front engine accessory drive and focuses on internal and external losses of the belt. To construct a predictive power loss model, external losses such as belt–pulley slip and bearings friction are modelled and implemented in addition to our previous modelling of belt-hysteresis losses. Simulation results are compared with experiments on a specific test bench which has been designed to permit measuring the power losses for any kind of belt transmission layout. The experiment results permit highlighting some particular power losses as belt-hysteresis losses, pulley-belt slip losses and bearing losses. The comparisons between simulation and experimental results permit validating the developed models.

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WASILCZUK, Filip, Michał WASILCZUK, and Michał WODTKE. "PROSPECTS OF DECREASING POWER LOSSES IN A HYDROSTATIC THRUST BEARING." Tribologia, no. 4 (August 31, 2017): 91–96. http://dx.doi.org/10.5604/01.3001.0010.6033.

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In numerous machines, axial load is carried by tilting pad thrust bearings known since the beginning of 20th century. These bearings are commonly bath lubricated, which is simple, does not require any additional pumps, and, due to this, such systems are highly reliable. In a contemporary technology, however, minimization of friction losses became an important goal of machinery improvement. Calculations based on elementary rules of fluid dynamics show that shearing losses in a specially designed hydrostatic bearing can be considerably smaller than the losses in a tilting pad hydrodynamic bearing. The aim of the research described in this paper was to check if the preliminary results can also be confirmed with the use of more advanced CFD calculations.

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31

Liu, Ying, Alexandr Kuznetsov, and Bowen Sa. "Simulation and Analysis of the Impact of Cylinder Deactivation on Fuel Saving and Emissions of a Medium-Speed High-Power Diesel Engine." Applied Sciences 11, no. 16 (August 19, 2021): 7603. http://dx.doi.org/10.3390/app11167603.

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The potential benefit of cylinder deactivation (CDA) on power and emission performances has been numerically investigated on a locomotive 16-cylinder diesel engine. A 1D model combined with a predictive friction model and a 3D combustion model based and validated on experimental data have been developed to simulate engine working processes by deactivating half of the cylinders by cutting off the fuel supply and maintaining/cutting off valve motions. The results demonstrate that CDA with the valves closed decreases the BSFC by 11% at 450 rpm and by 14% at 556 rpm with a load of 1000 N∙m, due to increased indicated efficiency and reduced mechanical losses. After deactivating cylinders, frictional losses of piston rings increase in the active cylinders because of the raised gas pressure and the lubricating oil temperature decrease. Friction losses of the main bearings and big-end connecting rod bearings decrease due to the overall load drop. In comparison with the normal operation, CDA with the valves closed decreases the BSCO emission by 75.26% and the BSsoot emission by 62.9%. As the EGR rate is 30%, CDA with the valves closed effectively reduces the BSNOx emission to 4.2 g/(kW·h) at the cost of a 0.8% increase in the BSFC and without the rise in the BSCO emission.

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Michlin, Y., and V. Myunster. "Determination of power losses in gear transmissions with rolling and sliding friction incorporated." Mechanism and Machine Theory 37, no. 2 (February 2002): 167–74. http://dx.doi.org/10.1016/s0094-114x(01)00070-2.

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Bernard, Mushirabwoba, Lahcen Belfals, Najji Brahim, and Lasri Abdelilah. "A comparative study of friction laws used in spur gear power losses estimation." Contemporary Engineering Sciences 9 (2016): 279–88. http://dx.doi.org/10.12988/ces.2016.512329.

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Giannetti, Guglielmo, Enrico Meli, Andrea Rindi, Alessandro Ridolfi, Zhiyong Shi, Anna Tangredi, Bruno Facchini, Tommaso Fondelli, and Daniele Massini. "Modeling and experimental study of power losses in a rolling bearing." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 8 (October 14, 2019): 1332–51. http://dx.doi.org/10.1177/1350650119882144.

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Due to the growing demand for very high performance in aeronautical mechanisms and systems, particular attention must be paid on the bearing modeling and design. In this framework, a fundamental role is played by high peripheral speed and very low power losses. Looking toward this direction, this paper presents an improved model of rolling bearings able to describe the system dynamic behavior and the important effect of different kinds of power losses (friction losses, fluid dynamic losses, etc.). The proposed model is characterized by a high numerical efficiency and allows the investigation of the rolling bearing behavior both under transient and steady conditions. A comparison between the experimental and simulated results is also presented in this paper. The analysis of the results is encouraging and shows a good agreement between experiments and model simulations.

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Reitschuster, Stefan, Enzo Maier, Thomas Lohner, and Karsten Stahl. "Friction and Temperature Behavior of Lubricated Thermoplastic Polymer Contacts." Lubricants 8, no. 6 (June 24, 2020): 67. http://dx.doi.org/10.3390/lubricants8060067.

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This work focuses on the friction and temperature behavior of thermo-elastohydrodynamically lubricated (TEHL) contacts under rolling-sliding conditions. For this purpose, a twin-disk test rig is used with a hybrid setup of plain and fiber-reinforced polyamide (PA) 66 and polyetheretherketone (PEEK) disks paired with case-hardened steel disks and three different lubricants. Experimental investigations include various lubrication regimes by varying sum velocity and oil temperature as well as load and slip ratio. The measured friction in thermoplastic TEHL contacts is particularly very low in the area of high fluid load portion, which refers to the large deformation of the compliant polymer surface. Newtonian flow behavior mainly determines fluid friction. The low thermal effusivity of polymers insulates the contact and can further reduce the effective lubricant viscosity, and thus the fluid friction. For low sum velocities, solid friction influences the tribological behavior depending on the solid load portion. Although the interfacial contact friction is comparably small, material damping strongly contributes to power losses and increases bulk temperature, which in turn affects the TEHL contact. Thus, loading frequency and the resulting bulk temperature are identified as one of the main drivers of power losses and tribological behavior of lubricated thermoplastic polymer contacts.

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Sachidananda, H. K., K. Raghunandana, and B. Shivamurthy. "Power loss analysis in altered tooth-sum spur gearing." MATEC Web of Conferences 144 (2018): 01015. http://dx.doi.org/10.1051/matecconf/201814401015.

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The main cause of power loss or dissipation of heat in case of meshed gears is due to friction existing between gear tooth mesh and is a major concern in low rotational speed gears, whereas in case of high operating speed the power loss taking place due to compression of air-lubricant mixture (churning losses) and windage losses due to aerodynamic trial of air lubricant mixture which controls the total efficiency needs to be considered. Therefore, in order to improve mechanical efficiency it is necessary for gear designer during gear tooth optimization to consider these energy losses. In this research paper the power loss analysis for a tooth-sum of 100 altered by ±4% operating between a specified center distance is considered. The results show that negative altered tooth-sum gearing performs better as compared to standard and positive altered tooth-sum gearing.

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37

Zhuykov, D. A., A. A. Zuev, and M. I. Tolstopyatov. "On Computing Losses in Blading Sections of Liquid Rocket Engine Pressurisation Stations." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 6 (135) (December 2020): 21–34. http://dx.doi.org/10.18698/0236-3941-2020-6-21-34.

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Designing more sophisticated contemporary liquid rocket engines requires a precise understanding of the hydrodynamics in the blading sections of the pressurisation station, which is most often a turbopump. Friction loss in blade passages and outlets forms a significant proportion of all losses. The paper shows that it is necessary to account for the initial region of hydrodynamically unbalanced flow in the boundary layer, which is most characteristic of relatively short passages in blading sections of liquid rocket engine turbopumps. We performed the analysis required to select friction drag laws for components of pressurisation station blading sections. We considered and proposed a method for numerically integrating a system of equations to determine the variation in characteristic thickness of a spatial boundary layer and friction loss, accounting for the inertial component of the flow core velocity, depending on which flow modes occur in the components of pressurisation station blading sections in a liquid rocket engine. We show that it is necessary to correctly select the friction laws and to take the initial region into account so as to precisely determine the power parameters

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Anderson, N. E., S. H. Loewenthal, and J. D. Black. "An Analytical Method to Predict Efficiency of Aircraft Gearboxes." Journal of Mechanisms, Transmissions, and Automation in Design 108, no. 3 (September 1, 1986): 424–32. http://dx.doi.org/10.1115/1.3258750.

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A spur gear efficiency prediction method previously developed by the authors was extended to include power loss of planetary gearsets. A friction coefficient model was developed for MIL-L-7808 oill based on disk machine data. This, combined with the recent capability of predicting losses in spur gears of nonstandard proportions, allows the calculation of power loss for complete aircraft gearboxes that utilize spur gears. The method was applied to the T56/501 turboprop gearbox and compared with measured test data. Bearing losses were calculated with large-scale computer programs. Breakdowns of the gearbox losses point out areas for possible improvement.

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Statsenko, V., A. Sukhorada, and M. Bernvskaya. "Research of Heat Input in Friction Stir Welding." Materials Science Forum 945 (February 2019): 634–38. http://dx.doi.org/10.4028/www.scientific.net/msf.945.634.

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Nowadays the most perspective, high-tech and productive process is friction stir welding. The most important part of this technology is to determine the temperature of the material in the stir zone. This parameter is easily counted by the amount of the heat input, put in the welding zone. We made experimental researches about the relation of the heat input, therotation speed and thediameter of the working tool. For that purpose an experimental scheme was chosen, which models a welding material (aluminum alloy AMg5) as an experimental tube 20 mm in diameter. The tool (shear steel P6M5) is modeled as a working plate. Measurements of the frictional moments depending on the rotation speed of the experimental working tube during the constant temperature are made on the prepared stand. By the experimental data the specific heat input and the heat power were counted on every concentric ring, 2 mm in width, in the end of the working tool, 20 mm in diameter. Also, the sum of the heat power for the whole tool during various rotation speed terms was counted too. On the stand throughout the experiment were determined all the thermal conductivity heat losses along the rod, which the experimental tube was pinned on, all the working plate heat losses through the gasket towards the working desk and the convection from the surface of the rotating experimental tube to the environment. According the data, any of these losses is from 3 to 10 percent. This is shown in the heat input counting.

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Zhang, Yanyan, Ziyuan Ma, Yan Feng, Ziyu Diao, and Zhentao Liu. "The Effects of Ultra-Low Viscosity Engine Oil on Mechanical Efficiency and Fuel Economy." Energies 14, no. 8 (April 20, 2021): 2320. http://dx.doi.org/10.3390/en14082320.

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The development of a sustainable powertrain requires improved thermal efficiency. Reducing frictional power losses through the use of ultra-low viscosity oil is one of the most effective and economical ways. To assess the potential for efficiency enhancement in a new generation of future engines using low-viscosity oils, a technical analysis was conducted based on numerical simulation and theoretical analysis. This study proposes a numerical method coupling the whole multi-dynamics model and lubrication model under mixed lubrication regimes. Then, load distribution was calculated numerically and verified experimentally. Finally, this paper compares the bearing load and frictional energy loss of the main bearings when using The Society of Automotive Engineers (SAE) 15W40 and SAE 0W20 oil. The results indicate that the application of ultralow-viscosity lubricant can reduce the hydraulic friction loss up to 24%, but the asperity friction loss would increase due to the reduction in load capacity. As a result, the design of a new generation of high efficiency internal combustion engines requires careful calculation and design to balance the trade-off relations between hydraulic friction and asperity friction.

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41

Jurnal, Redaksi Tim. "ANALISIS HEAD LOSSES PADA PENSTOCK UNIT III DI PERUM JASA TIRTA II UNIT JASA PEMBANGKIT PLTA IR. H. DJUANDA." Power Plant 6, no. 1 (November 27, 2018): 19–25. http://dx.doi.org/10.33322/powerplant.v6i1.70.

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One of the power plants in the labor system is hydropower, which is a power plant by utilizing water resources as its working fluid. In the operation of the hydropower requires high reliability sothat the energy production contuinitas to the load center or to the power system network can be more optimum. One of the components in the hydropower plant is penstock. Closed pipeline, whether it is laminar or turbulent, must have head losses. Head losses on penstock is a phenomenon of losses on the penstock so as to make the head value on the hydropower becomes reduced. At Penstock unit III PLTA Ir. H. Djuanda there are two phenomenon of head losses, namely: head losses major caused by friction penstock against water and minor head losses in the form of bend 900 with radius 4.375 m and 11.3 m from the axis penstock. Temperature changes affect the size of head losses, but they do not significantly affect penstock efficiency. At a temperature of 240C and a flow rate of 5m / s obtained a total head losses of 0606 m so as to make the potential of turbine inlet power down to 31,247 MW or 99.21%.

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42

Dolgopolova, E. N. "Energy losses and hydraulic friction of open and ice-covered river flow." Power Technology and Engineering 45, no. 1 (May 2011): 17–24. http://dx.doi.org/10.1007/s10749-011-0218-4.

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43

Tyurin, A. V., A. V. Burmistrov, A. A. Raykov, and S. I. Salikeev. "An Analysis of Power Characteristics of Oil-Free Scroll Vacuum Pumps." Proceedings of Higher Educational Institutions. Маchine Building, no. 08 (725) (August 2020): 37–43. http://dx.doi.org/10.18698/0536-1044-2020-8-37-43.

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This paper presents an analysis of the indicator power of an oil-free scroll vacuum pump based on the indicator diagrams obtained through high-speed pressure sensors. These values are compared with the results of calculations using a mathematical model of the pump working process. It is shown that the divergence of the calculated results and experimental values does not exceed 4%, which confirms the adequacy of the developed mathematical model. The total power of the scroll pump exceeds the indicator power by more than 2 times due to the friction losses between the face seals and disks of the reciprocal scroll elements, friction losses in the stuffing box seals and rolling bearings, as well as due to the coefficient of efficiency of the motor. The influence of the radial clearance between the scroll elements on the power consumption is considered. It is shown that at low pressures nearing the ultimate pressure, the power increases with the increased clearance, while at inlet pressures exceeding 40 kPa it decreases. The performed analysis can be used for selecting the optimal geometrical parameters of the scroll elements and increasing power efficiency of the pump depending on specific operating conditions.

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Jiao, Renqing, and Vanliem Nguyen. "Study on Lubrication Efficiency and Friction Power Loss of Engine Based on a Hybrid Hydrodynamic Model." International Journal of Automotive and Mechanical Engineering 18, no. 3 (September 19, 2021): 8859–69. http://dx.doi.org/10.15282/ijame.18.2.2021.02.0679.

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Friction loss is one of the main factors affecting engine power. Reducing friction power losses to improve the power of engines is a significant concern for designers. Especially, under the background of energy-saving and emission reduction, it is indispensable to carry out an in-depth investigation on engine bearing lubrication characteristics. Unlike the previous studies of separate modelling, a new modelling method of coupling the dynamic and lubrication model is proposed in this paper. The bearing capacity, friction force, friction coefficient and eccentricity ratio were taken as the evaluation criterion, and the influence of design parameters such as angular speed, bearing radius and width on the lubrication efficiency and friction power loss (LE-FPL) were studied. The results indicate that increasing the angular speed, bearing radius or width can effectively reduce the eccentricity ratio and raise the minimum oil film thickness, which is beneficial to improve the lubrication efficiency. However, the above methods to improve engine lubrication efficiency will lead to more power loss of engine to a certain extent. Therefore, studies on reducing the friction power loss for the engine and on improving the lubrication efficiency for the engine should be considered coordinately in the dynamic design and optimisation of the engine.

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Wang, Yong Cong, You Kun Zhang, and Yan Hui Lu. "Heat Analysis of Vehicle Drive Axle." Applied Mechanics and Materials 851 (August 2016): 299–303. http://dx.doi.org/10.4028/www.scientific.net/amm.851.299.

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The vehicle drive axle is one of the main sources of power loss in drivetrain system, and its improvements can have a significant impact on vehicle fuel economy. Gears churning loss, bearing friction loss and engaging friction loss all make a great contribution to the heat generation. The temperatures of lubricants, the gear tooth contacting surfaces, and the bearing surfaces are critical to the overall axle performance in terms of power losses, fatigue life, and wear. So it is important to understand the heat generation and dissipation in automotive drive axle. However, the quantities of understandings of drive axle temperature is limited and published information is deficient.In this paper, we establish the mathematical model of heat generation and dissipation to investigate the connection between thermal behavior and power loss. Power loss is consist of churning loss, bearing friction loss and engaging friction loss. And also we simulate the model to get the conclusion and then conduct the experiments to verify the correctness of the theories and models.

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Suh, K. Y., N. E. Todreas, and W. M. Rohsenow. "Mixed Convective Low Flow Pressure Drop in Vertical Rod Assemblies: I—Predictive Model and Design Correlation." Journal of Heat Transfer 111, no. 4 (November 1, 1989): 956–65. http://dx.doi.org/10.1115/1.3250811.

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A predictive theory has been developed for rod bundle frictional pressure drop characteristics under laminar and transitional mixed convection conditions on the basis of the intraassembly and intrasubchannel flow redistributions due to buoyancy for a wide spectrum of radial power profiles and for the geometric arrangements of practical design interest. Both the individual subchannel correlations and overall bundle design correlations have been formulated as multipliers applied to the isothermal friction factors at the same Reynolds numbers. Standard and modified subchannel friction factors have been obtained to be used with spatial-average and bulk-mean densities, respectively. A correlating procedure has been proposed to assess the effects of interacting subchannel flows, developing mixed convective flow, wire wrapping, power skew, rod number, and transition from laminar flow. In contrast to forced convection behavior, a strong rod number effect is present under mixed convection conditions in bundle geometries. The results of this study are of design importance in natural circulation conditions because the mixed convection frictional pressure losses exceed the corresponding isothermal values at the same Reynolds numbers.

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47

Koukoulopoulos, Eleftherios, and Christos I. Papadopoulos. "Piston ring performance in two-stroke marine diesel engines: Effect of hydrophobicity and artificial surface texturing on power efficiency." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 232, no. 8 (October 25, 2017): 940–63. http://dx.doi.org/10.1177/1350650117736638.

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In the present work, an algorithm for the solution of the Reynolds equation incorporating the Elrod–Adams cavitation model and appropriately modified to account for hydrophobic surfaces has been developed and solved by means of the finite difference method. The algorithm has been utilized to calculate the frictional characteristics of piston rings of a large two-stroke marine diesel engine, and to evaluate their performance, in terms of minimum film thickness, friction force, and power loss over a full-engine cycle, including time-dependent phenomena. For improving frictional behavior, two surface treatments of the piston ring surface have been studied, namely hydrophobicity and artificial surface texturing, which are introduced at appropriate parts of the ring face. Following a parametric analysis, optimal texturing and hydrophobicity design parameters have been identified for operation with maximum value of minimum film thickness and minimum friction losses. The present results demonstrate that substantial performance improvement can be achieved if hydrophobicity or artificial surface texturing is properly introduced at the faces of a piston ring.

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BEDNARCZYK, Sławomir, Ludomir JANKOWSKI, and Justyna KRAWCZYK. "THE INFLUENCE OF ECCENTRICITY CHANGES ON POWER LOSSES IN CYCLOIDAL GEARING." Tribologia 285, no. 3 (June 30, 2019): 19–29. http://dx.doi.org/10.5604/01.3001.0013.5430.

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Gearing is one of the most important rolling nodes in a cycloidal planetary transmission. It consists of gears whose outlines are created according to cycloidal curves and the rollers cooperating with them. The epicycloidal and hypocycloidal gearing can be distinguished. There are power losses during the transmission operation, due to the transmitted load and friction in the gearing. The paper presents an analytical method for determining losses in cycloidal gearing, taking into account the manufacturing deviations of the elements making this gearing. The analysis allowed determining the distribution of intertooth clearances and forces at the points of contact between the profiles and the rollers, and consequently the distribution of power losses in gearing. The distribution of intertooth forces was verified by elastooptic tests of the gears set with cycloidal gearing. The results of the calculations indicate that the influence of eccentricity changes on the distribution of intertooth forces is significant and also that the distribution of power losses in gearing is closely related to the distribution of intertooth forces and has a very similar character.

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Fatehallah, Hassan S., Zaid S. Hammoudi, and Lutfy Y. Zidane. "Effect of Oil Temperature on Load Capacity and Friction Power Loss in Point Contact Elasto-hydrodynamic Lubrication." Al-Nahrain Journal for Engineering Sciences 22, no. 3 (October 26, 2019): 180–86. http://dx.doi.org/10.29194/njes.22030180.

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This study presents a numerical analysis for point contact Elasto-hydrodynamic lubrication EHL. The oils used are (0W-30 and 10W-40) as lubricants. The pressure and film-thickness profiles for point contact EHL are evaluated. The aims of this study are to estimate the effect of oil’s temperature on friction force, coefficient of friction and load carrying capacity. By using FORTRAN program, the Forward-iterative method is used, to solve two dimensional (2D) EHL problem. The viscosity is updating in the solution by using Roeland’s model. After the convergence of pressure is done, the friction force, friction power losses, and friction coefficient are calculated. The temperature used ranges from (-20 to 120 oC). The results showed the film-thickness decreases with the increasing of temperature. Though the maximum pressure is not affected, only the pressure distribution and profile are changed, inlet pressure decreases and the pressure profile tends towards a hertzian (dry contact) one. The friction force and the coefficient of friction decrease with the increasing of temperature.

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von Backstro¨m, Theodor W., and Anthony J. Gannon. "Compressible Flow Through Solar Power Plant Chimneys." Journal of Solar Energy Engineering 122, no. 3 (July 1, 2000): 138–45. http://dx.doi.org/10.1115/1.1313528.

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Chimneys as tall as 1500 m may be important components of proposed solar chimney power plants. The exit air density will then be appreciably lower than the inlet density. The paper presents a one-dimensional compressible flow approach for the calculation of all the thermodynamic variables as dependent on chimney height, wall friction, additional losses, internal drag and area change. The method gives reasonable answers even over a single 1500 m step length used for illustration, but better accuracy is possible with multiple steps. It is also applicable to the rest of the plant where heat transfer and shaft work may be present. It turns out that the pressure drop associated with the vertical acceleration of the air is about three times the pressure drop associated with wall friction. But flaring the chimney by 14 percent to keep the through-flow Mach number constant virtually eliminates the vertical acceleration pressure drop. [S0199-6231(00)03003-3]

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Journal articles on the topic 'Friction power losses'

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