Ruhollah Shafaei - Yazd University- Iran
Mohammad Hadi Shafaei - Shiraz University- Iran
Asghar Dashti Rahmatabadi - Yazd University- Iran

To calculate various parameters in lubrication problems, it is not a reliable method to consider surfaces without roughness since this might lead to many errors. In order to get such parameters, there is a need to use a numerical method for solving equations.The combined effects of non-Newtonian rheology and surface roughness on the characteristics of lobed bearings have been investigated in this paper. The considered fluid in this study is a non-Newtonian micro-polar fluid. Two distinct roughness models, Tsann and Christensen, were applied for achieving the rough modified Reynolds equations. Moreover, the effects of the groove in the boundaries of each lobe on pressure distribution were examined. A contact model that takes the properties of engineering surfaces into account has been developed and implemented by using of the finite element method. There were good agreements between present and previous work.According to the results, as lobe number is increased, the peak of the pressure distribution is increased. On the other hand, adding groove in the boundary condition leads to decrease the peak of pressure distribution.

Surface roughness, Groove effects, Increasing lobe number, Micro-polar fluids, Finite element method