Heat-transfer crisis in channels

Abstract

1. A modern version of a look-up table has been developed for calculating the critical heat flux in round pipes on the basis of the combined work of specialists at Chalk River Laboratory (Canada), the Main Science Center of the Russian Federation — the Physics and Power Engineering Institute, and the Technical University in Braunschweig (Germany). The table is based on a databank on the critical heat flux density in pipes with a vertical rising flow of water. The bank includes a wide range of regime parameters. The table is intended for calculating the critical heat flux density in pipes with a diameter of 8 mm in a range of pressure, mass velocity, and critical mass steam content equal to 0.1–20 MPa, 0.25–8 Mg/(sec·m2), and from −0.5 to 1, respectively. Linear extrapolation is used to calculate qcr in intermediate regimes. An empirical relation is introduced in order to expand the applications of the look-up table to calculations in pipes with a different diameter. The table obtained on the basis of a combined Russian-Canadian databank contains, after the redundancies and clearly incorrect values are removed, 22946 values of the critical heat flux densit with an arithmetic mean and rms error of 0.69 and 7.82%, respectively. Assessment of the preceding versions and empirical correlations showed that this look-up table makes possible today the most accurate calculations and is applicable for a wide range of parameters.