This article is an experimental and numerical study on elastohydrodynamic behavior of a plain cylindrical journal bearing subjected to the radial loads. An experimental study conducted on the effects of applied load on the determination of the characteristics of a cylindrical journal bearing, with 100 mm diameter and a radial clearance of 0.09 mm. The bearing is made of steel backing material and babitted (88% tin) on its inner surface. Lubrication is insured using PM3 type oil which features good rheological properties as well as a large density. The operating conditions are variable, with the radial load ranging up to 10 kN and the rotational speed ranging up to 2000 r/min. The numerical analysis investigates the deformation effects on the bearing behavior. This analysis considers the impact of various parameters such as rotational speed up to 9000 r/min, radial load up to 150 kN. Finally, the numerical predictions have been validated in comparison with experimental data.

Purpose – This paper aims to investigate the fluid flow regime and the elastic effect in a plain cylindrical journal bearing subjected to highly severe operating velocity to better predict the behavior of the bearing for the turbulent flow regime. Design/methodology/approach – A numerical analysis of the behavior of an elastohydrodynamic for cylindrical journal bearing finite dimension coated with antifriction material in turbulent regime, is implemented using the code-ANSYS CFX. This analysis is performed by solving the Navier–Stocks equations of continuity by the method of finite volume for rotational speeds ranging from 6,000 to 15,000 rpm, that is to say for different Reynolds number. Findings – This study aims to better predict the elastic behavior in a journal bearing subjected to severe operating conditions. The speed of rotation varies from 6,000 to 15,000 rpm. Originality/value – The results clearly show that significant pressures are applied in the extreme case of speed, that is to say to the turbulent regime. There is an emergence of new rupture zone pressure, we do not usually see the regime established; the level of the supply groove. Displacement of shaft relative to the bearing is remarkable by introducing the elastic effect and the turbulent regime.

Purpose -The paper aims to analyze the evolution of the lubrication regime by studying the variation of friction coefficient with the rotational speed of the shaft and the impact of the applied load in the starting phase of a cylindrical journal bearing. The paper also aims to ensure that the oil layer is large enough for the rough edges of the outer layer of the bushing and the shaft cannot come into contact. The bearing is made of steel backing material and babbitted (88 per cent tin) on its inner surface. Design/methodology/approach -A numerical analysis is performed taking into account the thermal effect to better predict the operating performance of a hydrodynamic plain cylindrical journal bearing during the start-up and observe the variation of the heat production in bushing inner surface. The flow is modeled based on the Reynolds equation and discretized using the finite volume method. Findings -The evolutions of the start-up speeds of the bearing have remarkable influence on friction torque; average temperature and dissipated power increased with increasing speed and increasing load, but the maximum pressure and the eccentricity decreased with the increase of the start-up speed. The friction coefficient, minimum film thickness and attitude angle increase with elevation of start-up speed. Originality/value -For the start-up speed of 750, 1,000 and 1,800 rpm and an applied load of 1,000 N, the regime of lubrication of the bearing passes the hydrodynamic regime to the mixed regime; therefore, during start-up and under heavy loads, the bearing must move very quickly at these speeds to avoid contact of the inner surface of the bearing and the shaft. NomenclatureC ϭ bearing clearance [m] Cp ϭ specific heat [J/kg·k] C B ϭ friction torque of the bushing [Nm] e ϭ eccentricity of the shaft in the bearing [m] h ϭ film thickness [m] K ϭ thermal conductivity of the fluid [w/mK] L ϭ bearing length [m] m, n ϭ coefficients of McCoull and Walther relationship O B ϭ bush center O s ϭ shaft center p ϭ pressure [MPa] R B ϭ bushing radius [m] R s ϭ shaft radius [m] T ϭ fluid temperature [°C] T 0 ϭ initial temperature [°C] U B ϭ bushing speed along the X-axis [m/s] U s ϭ shaft speed along the X-axis [m/s] u, v, w ϭ velocity components in the fluid film [m/s] W ϭ radial load [N] x, y, z ϭ Cartesian coordinate [m] ␣ ϭ coefficient of thermal expansion [1/K] ␦ ϭ thermoelastic component [m] ϭ relative eccentricity ϭ e/C ϭ attitude angle [rad] ϭ dynamic viscosity [Pa·s] ϭ circumferential coordinate [rad] r ϭ angular coordinate in rupture zone ϭ oil density [kg/m 3 ] ϭ angular speed [rad/s] B ϭ angular speed of the buching [rad/s] S ϭ annular speed of the shaft [rad/s]

Surface texturing technology has been newly explored technique in the tribological domain, and this method is carried out to improve the displacement and performance of the Babbitt plain journal bearing with a textured surface. The numerical analysis is carried out to study the textured surface effect on the elastic behaviour of the journal bearing. First, the bearing is tested without texture; second, it is examined completely textured, by varying the operating parameters of the bearing. The performance is observed in a pressure profile, displacement, and shear stress, generated for each combination of radial loads, and rotational velocity of the shaft. The numerical modelling is used by solving the displacement equations by the finite element method to analyses bearing displacement for severe operating conditions. The results show that the elastic deformations for textured bearing, are important and preponderant for higher rotational speeds, and shear stresses are important for higher hydrodynamic pressures.

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