AN EXPERIMENTAL INVESTIGATION OF CRITICAL FLOW RATES OF SUBCOOLED WATER THROUGH SHORT PIPES WITH SMALL DIAMETERS

摘要

Critical two-phase flow rates of subcooled water through short pipes (L < 400 mm) with small diameters (D < 7.15 mm) have been experimentally investigated for wide ranges of subcooling (0 similar to 199 degrees C) and pressure (0.5 similar to 2.0 MPa). To examine the effects of various parameters (i.e., the location of flashing inception, the degree of subcooling, the stagnation temperature and pressure, and the pipe size) on the critical two-phase flow rates of subcooled water through short pipes with small diameters, a total of 135 runs were made for various combinations of test parameters using four different L/D test sections. Experimental results that show effects of various parameters on subcooled critical two-phase flow rates are presented in the form of graphs such as the dimensionless mass flux (G*) versus the dimensionless subcooling (Delta T*(sub)) curve. An empirical correlation expressed in terms of a dimensionless subcooling (Delta T*(sub)) is also obtained for subcooled two-phase flow rates through present test sections. Comparisons between the mass fluxes calculated by present correlation and a total of 679 selected experimental data points of 9 different investigators show that the agreement is fairly good except for very low subcooling data obtained from small L/D (less than 10) orifices. Copyright (C) 1996 Elsevier Science Ltd [References: 12]