Turbulent Free Convection in Near-Critical Water

Heat transfer from a vertical flat plate by turbulent free convection to water near its thermodynamic critical point was studied analytically and experimentally. The analytical method of solution involved an integral technique as well as assumptions dealing with Reynolds analogy, the Blasius wall shear stress, and suitable velocity and temperature profiles. Measurements were made of the heat flux from a platinum ribbon suspended in a pressure vessel containing the test water. The ribbon was heated electrically by direct current. Its temperature was determined by resistance measurement combined with a previously obtained resistance-temperature calibration. The experimental results indicate reasonable agreement with the analytical prediction but could be improved with a better method of evaluating the Prandtl number. A correlation of the experimental data was developed and is given in terms of the usual dimensionless parameters.