Experimental Study on Reflux Condensation inside a Tube Simulating a U Tube of a PWR (Pressurized Water Reactor) Steam Generator

摘要

A basic experimental study on reflux condensation was carried out in a single tube, vertical test section reproducing at full scale (I.D. 16.87 mm, length 7.14 m) the rising branch of a PWR U-tube steam generator. The secondary side of the steam generator was simulated through a jacket allowing circulation of cooling water. Controlled boundary conditions were pressure (55, 80, 105 bar), inlet steam flow rate (within 2.5 to 10 and 10/sup -3/ Kg/s), inlet cooling water temperature, tube entry geometry (sharp and round edge). A few experimental points were obtained in total reflux condensation, whereas the major part of the work was devoted to the determination of the countercurrent flow limitation. Experimental data were compared with different flooding correlations, showing a comparatively good agreement with the orginal Wallis correlation. Entry geometry has a marked effect, though lower than predictable, shifting the flooding limit to higher steam flow rates for round edge. Local heat transfer measurements were also performed; however comparison with correlation is restricted to complete reflux data. (Atomindex citation 19:105879)