Measurements of Hideout Phenomena in Tube-Support-Plate Crevices

An autoclave and a water treatment and monitoring system simulating the secondary side of a steam generator are used to investigate the hideout phenomena of sodium chloride in a tube-support-plate crevice. The primary-side heating tube is simulated by an internal heater. The experiments are performed at 1 atm pressure. The effects of heat flux, bulk concentration, crevice width, and the presence of a porous medium are investigated. It is found that the solute concentrates heavily near the upper end of the crevice. This concentration distribution in the axial direction is confirmed by a model developed in a parallel study. The hideout rate increases with increasing heat flux and bulk concentration. The concentration level in the crevice at a given time increases with increasing heat flux and bulk concentration and with decreasing crevice width. The presence of a porous medium in the crevice significantly enhances the concentration effect.