EVALUATION OF FRICTION LOSSES IN TEXTURED HYDRODYNAMIC TRIBO-UNITS OF PISTON MACHINES. PART 1. OVERVIEW OF MODELING TECHNIQUES
Keywords:
journal bearing, friction losses, cavitation, microgeometry, tribo-unitsAbstract
Requirements for efficiency and environmental of internal combustion piston engines (ICE) are increasing every year. Reducing friction losses is one of the promising ways to boost the internal combustion engine and increase the durability of its components. Among the general mechanical friction losses, special attention should be paid to hydrodynamic friction losses of various complexly loaded tribo-units (TU). These units are exposed to high temperature and mechanical stress, variable in time and magnitude. The use of microtexturing of the contacting surfaces allows to reduce the amount of friction losses and prevent “oil starvation”, as well as to increase the bearing capacity of the assembly due to the formation of many “micro wedges”, which contribute to an increase in the reaction of the lubricating layer. The use of texturing affects the formation of zones of divergence and turbulence, which is a poorly studied aspect in the modern literature. The texturing of the crankshaft bearings can be in the form of elliptical micro-dimples of various sizes. This work is presented in two parts. In the first part, special attention is paid to the analysis of scientific sources, methods of mathematical modeling of hydrodynamic phenomena in the lubricating layer. In the second part of the work, the theoretical results of the study will be presented using the example of a connecting rod bearing with different types of texturing of friction surfaces. Initial data will be based on experimental results. Calculations will be carried out in the Ansys Fluent software package and software developed by the authors. The purpose of this article is to consider the current theoretical basis of the physical phenomena and, based on this, the formation of a general algorithm for calculating frictional losses in a radial bearing with texturing.References
Coy, R.C. Practical applications of lubrication models in engines / R.C. Coy // Tribology In-ternational. – 1999. – No. 31 (10). – P. 563–571.
Ligier, J.L. Friction reduction and reliability for engines bearings / J.L. Ligier, B. Noel // Lubricants. – 2015. – No. 3. – P. 569–596.
Friction in Automotive Engines / H. Allmaier, C. Priestner, D.E. Sander, F.M. Reich // Tribology in Engineering. – 2013. – P. 149–184.
Путинцев, С.В. Механические потери в поршневых двигателях / С.В. Путинцев. – М.: МГТУ им. Н.Э. Баумана, 2011. – 288 с.
Harald Keferböck. Modellerstellung und Simulation von verlustbehafteten hochdyna-mischen mechanischen Systemen / Keferböck Harald // Technische Universität Graz. – 2014. – 99 p.
Hamilton, D. A theory of lubrication by micro-irregularities / D. Hamilton, J. Walowit, C. Allen // Journal of Basic Engineering. – 1966. – No. 88 (1). – P. 177–185.
Gropper, D. Hydrodynamic lubrication of textured surfaces: A review of modeling tech-niques and key findings / D. Gropper, L. Wang, T. Harvey // J Tribology International. – 2016. – No. 94. – P. 509–529.
A critical assessment of surface texturing for friction and wear improvement / C. Gachot, A. Rosenkranz, S.M. Hsu, H.L. Costa // Wear. – 2017. – No. 372–373. – P. 21–41.
Qiu, Y. On the prediction of cavitation in dimples using a mass- conservative algorithm / Y. Qiu, M.M. Khonsari // J Tribol. – 2009. – No. 131 (4). – P. 1–11.
Jakobsson, B. The finite journal bearing, considering vaporization / B. Jakobsson, L. Floberg // Goteborg, Sweden: Tran Chalmers University of Tech Gothenburg. – 1957. – P. 1–116.
Olsson, K.O. Cavitation in dynamically loaded bearings / K.O. Olsson // Goteborg, Swe-den: Tran Chalmers University of Tech Gothenburg. – 1965. – P. 308.
Mate, M.C. Tribology on the Small Scale / M.C. Mate, R.W. Carpick. – Oxford: Oxford University Press, 2008. – 333 p.
Brennen, C.E. Cavitation and Bubble Dynamics / C.E. Brennen. – Oxford: Oxford Univer-sity Press. – 1995 – 294 p.
ANSYS FLUENT 19.2 Theory Guide. – 2019. ANSYS Inc.
Mathematical basis and validation of the full cavitation model / A.K. Singhal, H.Y. Li, M.M. Athavale, Y. Jiang // ASME FEDSM’01. – 2001.
Zwart, P.J. A two-phase flow model for predicting cavitation dynamics / P.J. Zwart, A.G. Gerber, T. Belamri // In Fifth International conference on Multiphase flow. – 2004.
Schnerr, G.H. Physical and numerical modeling of unsteady cavitation dynamics / G.H. Schnerr, J. Sauer // In Fourth International Conference on Multiphase Flow. – 2001.
Исследование процесса смазки турбокомпрессора / В.И. Кубич, О.Г. Чернета, Е.А. Задорожная и др. // Вестник УрГУПС. Сер. «Механика машин и роботов». – 2019. – № 1. – С. 25–39.
Курликов, Д.А. Вплив явища турбулізації моторного масла на ресурс роботи ДВЗ (Влияние турбулизации моторного масла на ресурс работы ДВС) / Д.А. Курликов, В.И. Ку-бич // Проблеми енергоресурсозбереження в промисловому регіоні. Наука і практика: наук.-практ. конф. –Маріуполь: ДВНЗ «ПДТУ», 2017. – С. 37–38.
Прокопьев, В.Н. Применение алгоритмов сохранения массы при расчёте динамики сложнонагруженных опор скольжения / В.Н. Прокопьев, А.К. Бояршинова, К.В. Гаврилов // Проблемы машиностроения и надежности машин. – М.: Наука. – 2004. – № 4. – С. 32–38.
Основы работ в Ansys 17 / Н.Н. Федоров, С.А. Вальгер, М.Н. Данилов, Ю. В. Захаро-ва // М.: ДМК Пресс. – 2017. – 210 с.
What is y+? – https://www.simscale.com/forum/t/what-is-y-yplus/82394.
Von Kármán, Th. Mechanical Similitude and Turbulence / Th. Von Kármán // Tech. Mem. NACA. – 1931. – No. 611. – P. 58–76.
Schlichting (Deceased) H. Boundary-Layer Theory / H. Schlichting (Deceased), K. Ger-sten. – Springer, 2017 – 799 p. DOI:10.1007/978-3-540-95998-4_2
Kim, J. Turbulence statistics in fully developed channel flow at low Reynolds number / J. Kim, P. Moin, R. Moser // Journal of Fluid Mechanics. – 1987 – Vol. 177 (1). – P. 133. DOI:10.1017/
s0022112087000892




