The thermal conductivity of carbon dioxide in the critical region: III. Verification of the absence of convection

Abstract

In the preceding paper an anomalous increase of the thermal conductivity of CO 2 in the critical region was reported. To ascertain that this increase is not a result of convection, in the present paper the origin and contribution of convection during experimental measurements of the thermal conductivity is studied with special attention to the parallel plate method used. The conditions are derived which this parallel plate method must satisfy. It is shown that in the actual experiments published in the previous paper convection is negligible and the increase of the heat transfer observed in the critical region results from an increase of the thermal conductivity only.