Eulerian: Conjugate Heat Transfer Wall Boiling
This tutorial demonstrates how to set up a conjugate heat transfer wall boiling analysis in Simcenter STAR-CCM+. It simulates a nuclear fuel pin that is cooled using subcooled boiling under flow conditions typical in the first meter of a 3.7-m long BWR6 reactor channel.
The channel operates at 71.7 bar with an average heat flux of 524900 W/m2 at the cladding surface.
An axisymmetric, two-dimensional volume mesh of the boiling tube is provided, as shown below.

The fuel, cladding, and coolant are modeled as three finite regions. There is a gap between the fuel and the cladding. The properties of this gap vary as the fuel reacts and daughter constituents fill the space between the fuel and the cladding. Therefore, the gap is treated as an empirical contact resistance, with its thickness added to the fuel.