AN INVESTIGATION INTO THE BEHAVIOR OF COUNTER ROTATING FLOATING RING JOURNAL BEARING
باسم عبد العباس , عادل علوان, مصطفى باقر هنين الخفاجي
كلية الهندسة-جامعة بابل · العراق
A counter rotating floating ring journal bearing is a special type of journal bearing in which both the journal and the bearing are counter rotates about its centers in a proportional speed. A floating ring was maintained to rotate with an induced speed between the journal and the bearing.The effect of different parameters on the performance of such bearing, namely ring to journal speed ratio, bearing to journal speed ratio, clearance ratio, and radii ratio gets a little attention in the previous works. Also, it seems that there is no work, up to our knowledge, dealing with the effect of variable viscosity due to the variation of oil film temperature.Hence, a simplified thermal analysis of a plain journal bearing was extended and used to study the effect of oil film temperature on different bearing performance parameters.The classical Reynolds equation which was modified to include the effect of the two oil films (journal –ring and ring –bearing oil films) with a simplified energy equation are solved with an appropriate steady state equilibrium conditions. The effect of the oil film temperature has been included by using a suitable equation of state. The computational treatment consists of a numerical solution for the governing equations of the problem, using a finite difference technique. Two computer programs have been prepared for thermal and isothermal cases, which were written in (FORETRAN 09) language, to solve the governing equations of the problem.The results indicate that the ring speed and the coefficient of friction increases with increasing the bearing to journal speed ratio, decreasing the clearance and radii ratios. This investigation reveals that the oil film temperatures have a pronounced effect which cannot be neglected on the performance of counter rotating floating ring journal bearing.For conventional floating ring journal bearing(i. e when ωb= 9.9) the ring speed decreases with higher values of temperature resulting due to the oil shearing effect then the ring speed increases as the counter rotating speed of the bearing increases. In both the above cases the coefficient of friction shown to be decreases.