New representation of the dryout type critical heat flux.

An analysis of the physical processes taking place under conditions of disp ersed-annular flow which govern dryout type critical heat flux (CHF) has be en carried out. It has shown that the number of variables needed to describ e the critical phenomena can be reduced by the introduction of a new parame ter: the length over which dispersed-annular flow occurs L-and. The represe ntation of the CHF data in terms of the coordinate system (L-and, q(cr)") h as shown that the scatter of the data around the resulting regressions is c onsiderably less than that obtained for the traditional representation of t he CHF as a function of the thermodynamic quality at the end of the heated length. (C) 2000 Editions scientifiques et medicales Elsevier SAS.