A simple radial heat flow apparatus for fluid thermal conductivity measurements

Abstract

An absolute steady state radial heat flow apparatus employing guard cylinders has been constructed in brass and Pyrex glass and used for gas and liquid thermal conductivity investigations. The test fluid fills a 0.5 mm gap between concentric cylinders. The measurement of the power dissipated in the inner cylinder or emitter and evaluation of the temperature difference across the fluid annulus allow determinations of the thermal conductivity for gases and liquids to be made with an accuracy to 2%.