Simultaneous Determination of Thermal Diffusivity and Thermal Conductivity of Liquids by the Laplace Transform Method

摘要

References(16) A new unsteady-state method for measuring simultaneously the thermal dilfusivity and the thermal conductivity of liquids is presented. The method utilizes the principle of the Laplace transform and has the advantage of measuring these two properties under arbitrary heating or cooling conditions imposed on the test liquid, where unidirectional heat flow and a uniform temperature profile at the initial stage are conditions of testing. A measuring theory is developed for a measuring system wherein test liquid is intruded between a pair of flat reference samples whose properties are known. The characteristics and measuring errors of the method are discussed. An apparatus in which low-expansion borosilicate glass is used as the reference sample is made on an experimental basis. The method is verified by measuring both the thermal diffusivity and the thermal conductivity of water, toluene and NaCl solution.