AN EXPERIMENTAL STUDY OF THE HEAT TRANSFER PERFORMANCE OF A RECTANGULAR TWO-PHASE NATURAL CIRCULATION LOOP

An experimental study is presented for the heal transfer performance of a rectangular, two-phase, natural-circulation loop with water-steam as the working fluid. Local temperature measurements of the core fluid and the wall were made, and the overall heat transfer coefficients of the evaporator; the condenser, and the loop system were obtained and correlated in terms of the fluid properties, heal flux conditions, and the liquid charge level. An overheat phenomenon at very low charge level was also observed. Result of a preliminary analysis shows that if the liquid charge level is below the fractional volume of the connecting tube between the condenser and the evaporator; an overheat phenomenon will occur.