Heat-transfer degradation boundary in supercritical-pressure flow

A brief presentation of the modern ideas about the mechanisms of degradation of heat transfer with supercritical parameters is given. The best known relations for calculating the limits of degradation of heat tansfer in tubes in order to determine the working relations are presented. The recommendations are compared with the latest experimental data. It is shown that the temperature of the walls affects the start of the region with degraded heat transfer A generalized relation, making it possible to determine to within 20% the onset of the degradtion of heat tansfer for different coolants (water carbondioxide, freon-12), is proposed on the basis of the theory of thermodynamic similarity.