Problem
Understanding shell side flow in boilers is essential for ensuring plant reliability and performance. Plant performance is often limited by the maximum permissible boiler duty. The higher the duty; the greater the water circulation required to keep temperatures in the boiler stable. The problem is that the relationship between boiler duty and circulation ratio isn’t easy to calculate, and shell side flow distributions are generally not well understood.

Solution
Multiphase computational fluid dynamics (CFD) simulations of boilers provide an opportunity to document and understand how vapour is produced while also helping to identify potential hot spots and regions where departure from nucleate boiling (DNB) could occur.

Result
CFD modelling of boilers opens up possibilities of improving plant efficiency and operational reliability. Specifically, the ability to understand how boiler design, circulation ratios and duty affect localised heat flux distributions and the potential for the onset of steam blanketing.