Experimental determination of the viscosity and thermal conductivity of fluids

Abstract

The paper reviews the author's experience gained by his research on viscosity and thermal conductivity. The paper begins with a general discussion of the principles which must govern an experimenter who wishes to organize precise and accurate measurements of a transport property of a fluid. Emphasis is placed on the need to maintain a state close to equilibrium, to secure hydrodynamic stability, to formulate a faithful mathematical model of the process and to secure a high degree of resolution in the apparatus. The paper then proceeds to establish the principles which govern the measurement of viscosity in an oscillating-body instrument and briefly describes three such apparatus from the author's experience and one constructed in Trondheim by Tørklep and Øye. The section on thermal conductivity concentrates on the author's hot-wire, transient instrument, and discusses the principle of its operation and its potential for use in liquids. The last section describes the contribution that the creation of a large body of accurate data on viscosity and thermal conductivity has made to the development of a completely reliable method of calculating these quantities for low-density monatomic gases and their multicomponent mixtures. This development is recounted here to serve as a possible model for the creation of a similar schema for the calculation of the transport properties of solutions.