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  • 1
    Electronic Resource
    Electronic Resource
    Effect of viscous dissipation on the lubrication characteristics of micropolar fluids (1994)
    Springer
    Acta mechanica 105 (1994), S. 57-68 
    Details
    ISSN: 1619-6937
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Thermohydrodynamic solutions are presented for a finite journal bearing lubricated with micropolar fluid. Comparison with isothermal results, assuming that viscosity remains at the inlet temperature, is also given. Results indicate the heat generation due to viscous dissipation plays an important role on the load-carrying of a journal bearing lubricated with micropolar fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01183942
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Effect of viscous dissipation on the lubrication characteristics of micropolar fluids (1994)
    Springer
    Details
    Publication Date: 1994-03-01
    Print ISSN: 0001-5970
    Electronic ISSN: 1619-6937
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
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    PAPER CURRENT
  • 3
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    Simultaneous pressure measurement and high-speed photography study of cavitation in a dynamically loaded journal bearing (1993)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Cavitation of the oil film in a dynamically loaded journal bearing was studied using high-speed photography and pressure measurement simultaneously. Comparison of the visual and pressure data provided considerable insight into the occurence and non-occurrence of cavitation. It was found that (1), cavitation typically occurred in the form of one bubble with the pressure in the cavitation bubble close to the absolute zero; and (2), for cavitation-producing operating conditions, cavitation did not always occur; with the oil film then supporting a tensile stress.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME, Transactions, Journal of Tribology (ISSN 0742-4787); p. 88-95.
    Format: text
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  • 4
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    Two reference time scales for studying the dynamic cavitation of liquid films (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Two formulas, one for the characteristic time of filling a void with the vapor of the surrounding liquid, and one of filling the void by diffusion of the dissolved gas in the liquid, are derived. By comparing these time scales with that of the dynamic operation of oil film bearings, it is concluded that the evaporation process is usually fast enough to fill the cavitation bubble with oil vapor; whereas the diffusion process is much too slow for the dissolved air to liberate itself and enter the cavitation bubble. These results imply that the formation of a two phase fluid in dynamically loaded bearings, as often reported in the literature, is caused by air entrainment. They further indicate a way to simplify the treatment of the dynamic problem of bubble evolution.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME, Transactions, Journal of Tribology (ISSN 0742-4787); 114; 3, Ju
    Format: text
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  • 5
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    Frequency effects on the stability of a journal bearing for periodic loading (1992)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: The stability of a journal bearing is numerically predicted when an unidirectional periodic external load is applied. The analysis is performed using a cavitation algorithm, which mimics the JFO theory by accounting for the mass balance through the complete bearing. Hence, the history of the film is taken into consideration. The loading pattern is taken to be sinusoidal and the frequency of the load cycle is varied. The results are compared with the predictions using Reynolds boundary conditions for both film rupture and reformation. With such comparisons, the need for accurately predicting the cavitation regions for complex loading patterns is clearly demonstrated. For a particular frequency of loading, the effects of mass, amplitude of load vibration and frequency of journal speed are also investigated.
    Keywords: MECHANICAL ENGINEERING
    Type: ASME, Transactions, Journal of Tribology (ISSN 0742-4787); 114; 107-115
    Format: text
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  • 6
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    Simplified solution for elliptical-contact deformation between two elastic solids (1977)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: A linear regression by the method of least squares is made on the geometric variables that occur in the equation for elliptical-contact deformation. The ellipticity and the complete elliptic integrals of the first and second kind are expressed as a function of the x,y-plane principal radii. The ellipticity was varied from 1 (circular contact) to 10 (a configuration approaching line contact). The procedure for solving these variables without the use of charts or a high-speed computer would be quite tedious. These simplified equations enable one to calculate easily the elliptical-contact deformation to within 3 percent accuracy without resorting to charts or numerical methods.
    Keywords: MECHANICAL ENGINEERING
    Format: text
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  • 7
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    Simplified contact analysis (1978)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A simple and straightforward method for calculating the elastic deformation at the center of contact between two solids with different radii of curvature is proposed instead of the conventional contact deformation analysis for ball bearings, gears, and cams, which usually involves tedious iterative procedures or the use of design charts. Ellipticity of the contact is approximated from a least-squares power fit. Simplified expressions are derived which allow rapid calculation of deformation from the material properties and geometry of the contacting elements.
    Keywords: STRUCTURAL MECHANICS
    Type: Machine Design; 50; Mar. 9
    Format: text
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  • 8
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    On the performance of finite journal bearings lubricated with micropolar fluids (1989)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A study of the performance parameters for a journal bearing of finite length lubricated with micropolar fluids is undertaken. Results indicate that a significantly higher load carrying capacity than the Newtonian fluids may result depending on the size of material characteristics length and the coupling number. It is also shown that although the frictional force associated with micropolar fluid is, in general, higher than that of a Newtonian fluid, the friction coefficient of micropolar fluids tends to be lower than that of the Newtonian.
    Keywords: MECHANICAL ENGINEERING
    Type: STLE Tribology Transactions (ISSN 0569-8197); 32; 155-160
    Format: text
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  • 9
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    Starvation effects on the hydrodynamic lubrication of rigid nonconformal contacts in combined rolling and normal motion (1987)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The effect of inlet starvation on the hydrodynamic lubrication of lightly loaded rigid nonconformal contacts in combined rolling and normal motion is determined through a numerical solution of the Reynolds' equation for an isoviscous, incompressible lubricant. Starvation is effected by systematically reducing the fluid inlet level. The pressures are taken to be ambient at the inlet meniscus boundary and Reynolds' boundary condition is applied for film rupture in the exit region. Results are presented for the dynamic performance of the starved contacts in combined rolling and normal motion for both normal approach and separation. During normal approach the dynamic load ratio (i.e. ratio of dynamic to steady state load capacity) increases considerably with increase in the inlet starvation. The effect of starvation on the dynamic peak pressure ratio is relatively small. Further, it has been observed that with increasing starvation, film thickness effects become significant in the dynamic behavior of the nonconformal contacts. For significantly starved contacts the dynamic load ratio increases with increase in film thickness during normal approach and a similar reduction is observed during separation. A similar effect is noted for the dynamic peak pressure ratio.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ASLE Transactions (ISSN 0569-8197); 30; 91-99
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  • 10
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    Theoretical modeling of the vapor cavitation in dynamically loaded journal bearings (1985)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A theoretical investigation is made of the evolution of a vapor-bubble for a submerged journal bearing under dynamically loaded conditions using the Elrod algorithm. This method conserves mass throughout the computational domain. A comparison study is performed to determine some of the consequences of applying a nonconservative theory (pseudo-Gumbel BC) to a dynamic problem. A complete dynamic cycle of a journal whirling in a circular path is chosen for the basis of comparison. Significant differences are observed in the load components near the end of the cycle. Further, good agreement with experiment is found for stationary and nonstationary cavitation.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: ASME PAPER 85-TRIB-51
    Format: text
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