Exchanging Heat Transfer Coefficients

In convective heat transfer studies, the local heat flux at the wall is given by Newton’s law of cooling, that is,

where $h$ is the heat transfer coefficient, $T_w$ is the wall temperature, and $T_r$ is the fluid reference temperature. Examples of fluid reference temperatures are the near-wall temperature, or the mean fluid temperature. An important point is that the heat transfer coefficient and reference temperature are paired; there are many pairs that give the same wall heat flux.

In conjugate heat transfer calculations, where all calculations are part of the same simulation, there is no concern over the choice of heat transfer coefficient and reference temperature. In conjugate simulations the heat flux and wall temperature are calculated by the implicitly coupled system of equations. In co-simulation calculations, where the fluid and solid parts of the geometry are treated separately, you must choose the information to exchange at the interface between the simulations.

This section of the documentation is intended to help you choose the right approach for exchanging heat transfer coefficients.