The Heat Conduction contact model calculates the heat flux based on the relative
temperatures and the particle overlap.
This model calculates the heat flux between Particle-Particle and Particle-Geometry
contacts. This model must be used with Update Temperature particle body force to
complete the calculation. The Temperature Update particle body force allows the
inclusion of an external heat source and is where each particle temperature is
calculated based on the heat flux calculated in the contact model and a given external
heat flux.
The calculated heat flux is applied only to particles to update their
temperature. If you enable the option
Allow different temperatures in one
geometry, a heat flux value will also be stored for each triangle in
the Geometry. These values can then be used by an external tool (such as a coupled
application) to update the temperature of individual triangles. If this option is
disabled, the Geometry temperature remains constant, while particle temperatures are
updated according to the calculated heat flux. For GPU configurations, performance
is generally higher when this option is not enabled. You can set an initial,
homogeneous temperature for each Geometry section through the model GUI. If you do
not provide the temperature of one Geometry, the heat flux between the particles and
that Geometry is not computed.
Note: In versions prior to 2026,
the Geometries with undefined temperature were assigned 0 K.
For
dilute phase simulations, convective heat transfer is dominant and conduction
between the particles or wall can be neglected. However, for dense phase, contacts
between particles are significant such that conductive heat transfer must be taken
into account. A single phase DEM simulation on heat transfer in granular flow in
rotating vessels provides a simple approach in modeling inter-particle heat
transfer. This model is based on the work of (H&A) Chaudhuri (Chaudhuri, Muzzio,
and Tomassone 2006).
The heat flux between the particles is defined
as:
Where the contact area is incorporated in the
heat transfer coefficient c and is defined as:
Where F
N is the normal force,
r
* the geometric mean of the particles radii from the Hertz’s elastic
contact theory and E
* is the effective Young’s modulus for the two
particles. The bracketed term on the RHS of the equation models indicates the
contact area between particles.
Note: You must use this
contact model along with the Temperature Update Body Force
model.
