Wear, 70 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA (1981) 311 - 319 0 Elsevier Sequoia S.A., Lausanne - Printed in The Netherlands NON-NEWTONIAN SQUEEZE FILMS IN JOURNAL CHANDAN SINGH and PRAWAL SINHA 311 BEARINGS Department of Mathematics, Indian Institute of Technology, Kanpur, Kanpur 208016 (India) (Received July 31,198O; in revised form December 5,198O) Summary Non-newtonian behaviour, which occurs in various lubrication problems, was studied using a power law model. The geometry considered was that of a journal bearing. Bearing characteristics, i.e. the load capacity and the response time, were obtained for full-journal and half-journal bearings and were com- pared with each other. As the flow behaviour index n increases the load capacity ratio and the response time ratio decrease. 1. Introduction The importance of non-newtonian fluids such as molten plastics, pulps and emulsions in chemical engineering practice has motivated many investi- gators to analyse the behaviour of these fluids in motion. Such fluids violate the newtonian postulate that the stress tensor is directly proportional to the deformation tensor. Lubrication and rheology have become mutually important owing to the growing awareness of the complexity of the lubricant reaction to severe and to transient stress conditions, the demand for effective high speed highly loaded machine elements and the use of synthetic lubricants. Non-newton&m behaviour is frequently observed in lubrication processes; it is caused by severe operational requirements, the use of additives, the use of lubricants containing long-chain molecules or lubricants which are loaded with dirt or metal particles. In contrast to the newtonian hypothesis, where a linear relationship exists between the shear stress and the shear rate, non-newtonian fluids may generally be characterized by the constitutive relation shear stress = consistency X rate of shear where the consistency can be a function of both the shear stress and the shear rate. Various theories based on the above relation have been proposed. One such model is the power law model. For a power law fluid the relation between the stress tensor Tij and the rate of deformation tensor eij is given by