Experemental investigations of transcritical heat transfer on an electrically heated model of a fuel assembly

The purpose of this work was to obtain experimental information on the temperature state of fuel elements in the transcritical region and to develop methods for calculating the heat-emission coefficient. The following region of regime parameters was investigated: pressure 11.7–16.7 MPa, temperature at the entrance into the fuel-assembly model 200–285°C, mass velocity 700–1900 kg/(m2·sec).The existence of a definite transcritical power reserve was confirmed experimentally. The results of the investigations showed that in the experimental range of regime parameters the coolant temperature at the entrance into the fuel-assembly model has the strongest effect on the transcritical reserve. As temperature increases, the transcritical reserve increases. A method for calculating the heat-emission coefficient in the transcritical region was developed on the basis of the experimental data obtained, 5 figures. 2 references.