Volume 15, Issue 4 (6-2015)                   Modares Mechanical Engineering 2015, 15(4): 41-50 | Back to browse issues page

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Abstract:   (6422 Views)
One of the challenging problems of tribology is cam and follower elastohydrodynamic lubrication due to the simultaneous effect of various lubrication mechanisms. These mechanisms are transient, squeeze film, elastic deformation of contacting surfaces and variation of lubricant properties with pressure. In this paper, besides studying the mentioned factors, the effect of using a non-Newtonian lubricant such as grease is numerically investigated. The lubrication governing equations and Oswald’s grease behavior equation have been discretized using finite difference technique. The system of equation has been solved via Multi-Grid method which is an advanced iterative method in solving system of partial differential equations. The results are showed for Newtonian oil comparing to grease for different cam rotational speed. Also different grease behaviors are investigated. The results are verified by a comparison to the results obtained using the famous Newton-Raphson method. Finding shows that the minimum lubricant thickness as well as the maximum pressures is lower when using grease compared to the case that a Newtonian lubricant is used. In the case of Newtonian lubricant, increasing the speed results in an increase in the lubricant film thickness but it is shown that the speed does not affect the lubricant thickness in the case of non-Newtonian lubricant.
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Received: 2014/11/21 | Accepted: 2015/01/18 | Published: 2015/02/17

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