A Higher Order Perturbational Approach in the Lubricated EHL Contacts With Non-Newtonian Lubricant

In previous papers [7–9], investigations have been made on the influence of several kinds of non-Newtonian lubricants on the line contact EHL by using a first-order perturbational method. The practical engineering applications have been also tried successfully through papers [10–14]. However, when the slide/roll ratio reduces to zero the derived Reynolds equations become either the exact equations for a Newtonian lubricant or totally invalid. This, of course, is not the case for a natural non-Newtonian fluid. The facts show the limitation of the first-order method and also implies that with a tendency of decreased slide/roll ratio the first-order perturbational approach may bring a larger error and cannot describe accurately the behavior of non-Newtonian lubricants in the lubricated region. To improve it, a higher-order perturbational procedure is proposed in this paper.