Evaluation and countermeasures of convective heat transfer on thermal conductivity measurement using the Peltier effect and application to supercritical CO2

In the previous paper, the present authors reported a newly developed metho d of thermal conductivity measurement for fluids using a thermoelectric mod ule. It was very simple and effective for samples in supercritical states. However, the countermeasures against thermal perturbation were insufficient . In the present work, some improvements have been made on the apparatus to eliminate thermal convection. The convective heat transfer enter on the me asurement has been evaluated by varying the temperature difference across t he sample layer. It has been found that the convection-free conductivity fo r critical and supercritical fluids can be determined by extrapolation of t he temperature difference to 0. The thermal conductivity of supercritical C O2 measured by the improved method is presented, including the states near the critical point.