Original scientific paper
THE CONNECTION BETWEEN THE ELECTROCHEMICAL PROPERTIES OF METALS AND LUBRICANT RHEOLOGY IN CYLINDRICAL TAYLOR-COUETTE FLOW
Nicolae-Adrian Palusan
orcid.org/0000-0002-5019-710X
; Total Romania
Abstract
The behavior of fluids in developing flow regions is of importance for many applications of drag reducing surfactant solutions, such as hydronic cooling and heating systems. Moreover is the chemical or electrochemical effect important, which appears at the interface between the metal surface and fluid. A very thin layer of fluid is supposed to be adsorbed on the metal surface as a consequence of this chemical or electrochemical effect. A specific Couette rheometer has been developed for the purpose of emphasizing that chemical or electrochemical effect in the cylindrical Taylor-Couette flow. In order to perform time-dependant viscometer measurement on viscous fluids, the fluids having a non-Newtonian behavior related to a long “characteristic time”, a new type of viscometer with a sensitive dynamic has been developed in a cooperation between our Research laboratory, the Tribology laboratory of Technical University of Brasov and the Chemical Instruments laboratory of Timisoara Technical University.
The Couette cell is made of two moving concentric cylinders (the outer cylinder is the driver and the inner cylinder is driven). The inner cylinder is moving supported by an air bearing (frictions are avoided) and is interchangeable so that there can be variations of the gap dimensions (between the cylinders) and the materials which are used to build the inner cylinder. When a viscous fluid is sheared between two concentric cylinders undergoing differential rotation, the free surface of the fluid is deformed as a consequence of that shearing motion, as well as of both gap dimension (between the cylinders) and the material which is used to build the inner cylinder (different surface tension effect for different material). This paper is a rheological study on fluids (in general) and lubricants (in particular) in Taylor-Couette flow.
Keywords
Couette apparatus; Taylor-Couette flow; shear stress; air bearing; apparent viscosity; rotational viscosity; potential of zero charge
Hrčak ID:
182964
URI
Publication date:
15.5.2017.
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