“…To accurately calculate the film pressure, the lubricant viscosity needs to be updated with the temperature obtained with equation (4). In doing so, the non-vapored lubricant viscosity is calculated with the following viscosity-temperature relation 28 where μ0 represents the initial viscosity of the lubricant when the environmental temperature T 0 is 40℃ (i.e. 313.15 K).…”
Effects of operation parameters on the noise of the compound textured journal bearing are analyzed using computation fluid dynamic method and broadband noise source theory. After a three-dimensional model of the compound textured bearing is established, the lubrication performances of the bearing are compared under the isothermal and thermal situations. Further, the noise performances of the textured and smooth bearings are studied at the varied operation parameter. Numerical results show that appropriately decreasing the eccentricity ratio or rotational speed can reduce the noise of the compound textured bearing. Moreover, there is a critical length–diameter ratio of the bearing for suppressing the noise of the compound textured bearing. A part of the above conclusions is also verified experimentally.
“…To accurately calculate the film pressure, the lubricant viscosity needs to be updated with the temperature obtained with equation (4). In doing so, the non-vapored lubricant viscosity is calculated with the following viscosity-temperature relation 28 where μ0 represents the initial viscosity of the lubricant when the environmental temperature T 0 is 40℃ (i.e. 313.15 K).…”
Effects of operation parameters on the noise of the compound textured journal bearing are analyzed using computation fluid dynamic method and broadband noise source theory. After a three-dimensional model of the compound textured bearing is established, the lubrication performances of the bearing are compared under the isothermal and thermal situations. Further, the noise performances of the textured and smooth bearings are studied at the varied operation parameter. Numerical results show that appropriately decreasing the eccentricity ratio or rotational speed can reduce the noise of the compound textured bearing. Moreover, there is a critical length–diameter ratio of the bearing for suppressing the noise of the compound textured bearing. A part of the above conclusions is also verified experimentally.
“…Roy et al [19] found that fluid temperature increased, viscosity and carrying capacity decreased because of friction heat. Sharma et al [20] presented that least oil film thickness decreased, stiffness and damping coefficient and instability speed changed considering thermal effect.…”
Section: Study On Thermal Effects and Non-newtonian Fluids On Bearmentioning
Abstract-Hybrid sleeve bearings are normally lubricated with high viscosity lubricant, the temperature of oil film increases with the increase of rotating speed. The low viscosity lubricant can decrease the temperature, which is the efficient method to increase the rotating speed of hybrid sleeve bearings. A current situation of the published research works on high speed sleeve bearing with low viscosity lubrication was summarized. The structure of high speed sleeve bearing with low viscosity lubrication was introduced, the effect of wall slip, cavitation, surface roughness, temperature and et al. on bearing properties was analyzed, and the significance of lubrication study for high speed journal bearing with low viscosity lubricant was discussed.
“…The damping efficiency of SFDs is influenced by several parameters, including the damper geometry (i.e., diameter and length), rotor operating speed, and lubricant properties (i.e., density and viscosity). Earlier research have focused on providing greater insight into different features of SFDs, particularly the role of lubricant cavitation, 1–4 and thermohydrodynamics 5–7 that have aimed at improving SFD performance in SFD-supported rotor systems. Figure 1.The schematic representation of a conventional squeeze film damper.…”
This work represents closed-form analytical expressions for the operating parameters for short-length open-ended squeeze film dampers, including the lubricant velocity profiles, hydrodynamic pressure distribution, and lubricant reaction forces. The proposed closed-form expressions provide an accelerated calculation of the squeeze film damper parameters, specifically for rotordynamics applications. In order to determine the analytical solutions for the squeeze film damper parameters, the thin film equations for lubricant are introduced in the presence of the influence of lubricant inertia. Subsequently, two different analytical techniques, namely the momentum approximation method, and the perturbation method are applied to the thin film equations. Moreover, the solution for the lubricant flow equations are analytically determined to represent closed-form expressions for the hydrodynamic pressure distribution and the velocity component profiles in squeeze film dampers. Additionally, the expressions for the hydrodynamic pressure distribution are integrated over the journal surface, either numerically or analytically by using Booker’s integrals, to develop expressions for the fluid film reaction forces. Lastly, the developed squeeze film damper models are incorporated into simulation models in Matlab and Simulink®, and the results are compared against a well-established force coefficient model to verify the accuracy of the calculations. The results of the simulations verify the effect of the lubricant inertia components, namely the convective and temporal (i.e., unsteady) inertia components on the squeeze film damper dynamics, including hydrodynamic pressure distribution and fluid film reaction forces. Additionally, the simulation results suggest a close agreement between the proposed models and the results in the literature.
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