High-quality critical heat flux in horizontally coiled tubes

Abstract

An investigation on the high-quality dryout in two electrically heated coiled tubes with horizontally helix axes is reported. The temperature profiles both along the tube and around the circumference are measured, and it is found that the temperature profiles around the circumference are not identical for the cross-sections at different parts of the coil. The “local condition hypothesis” seems applicable under present conditions, and the critical heat fluxqcrdecreases with increasing critical qualityxcr. The CHF increases as mass velocity and ratio of tube diameter to coil diameter (d/D) increases, and it seems not to be affected by the system pressure. The CHF is larger with coils than that with straight tubes, and the difference increases with increasing mass velocity andd/D.