A MODIFIED APPROACH OF SQUEEZE EFFECTSIN POROUS MEDIA IMBIBED WITH NEWTONIAN FLUIDS

Abstract

An innovative self-supporting lubrication mechanism based on porous media is studied in the laboratory of University Politehnica of Bucharest under the name of ex-poro-hydrodynamic lubrication. The squeeze of a highly deformable porous material imbibed with a Newtonian fluid under the action of a normal load, causes the fluid to be expelled through the pores. During compression, the porosity of the material decreases significantly, and so, the permeability. As a consequence, the resistance to flow increases and generates higher pressures. The model is based on Darcy equation of flow and takes into account the permeability dependence on porosity, defined using Kozeny-Carman law. The solution yields from two conservation laws, the conservation of the flow rate and conservation of the solid fraction which are independently used. By correlating the two laws and reformulating the work using the corrected form of the corresponding equations, a more accurate description of the process is obtained. By comparing the previous and the modified model, it is demonstrated that the previous model underestimated the force up to two times.