Thermal and hydraulic testing of tube support crevice

The purpose of this project was to improve the understanding of the interrelationship among boiling heat transfer, chemical concentration, and particulate deposition in and around tube-tube support and flow distribution plate crevices. Since deposition of particulates and concentration of corrosive chemicals can lead to support plate corrosion and tube degradation, an understanding of these processes is important to design and operating practice, with the objective of avoiding conditions which may cause corrosion or wear. The specific project objectives are: to measure the tube wall superheat distribution for various tube support and flow distribution plate configurations; to measure critical heat flux within the crevice of tube support and flow distribution plate configurations; to determine whether dryout can be produced within crevices by precipitating an insoluble chemical; to establish the propensity for magnetite to collect preferentially in crevices and produce dryout; to establish the potential for plugging crevices by the deposition of magnetite; and to determine the denting possibility of the tubing adjacent to various tube support and flow distribution baffle configurations in the presence of a bulk secondary environment. Results of thermal and hydraulic testing of flow distribution baffle and support plate geometries, such as cylindrical holes of various diameters, flat and concave land quatrefoils, flat strap grids, and octagonally shaped holes, in all volatile treatment (AVT) water without precipitates or particulate matter are reported