For generalized Newtonian flows, Ansys Polyflow can calculate the heat generation per unit time and per unit volume (or per unit area for a 2D planar case) that is generated under the given flow conditions. The heat generation originates from the work of internal forces. In addition to the viscous and wall friction heating, Ansys Polyflow evaluates the dissipated power, which is the integral of the viscous and wall friction heating over the flow domain. When wall slippage is defined, the calculation of the dissipated power also considers the contribution originating from the slipping force, and results are provided for the volume dissipated power and the heat generated from slipping.
It is not necessary to solve a nonisothermal problem in order to compute the viscous and wall friction heating. Ansys Polyflow can calculate the viscous dissipation that occurs without actually solving the energy equation. Also, Ansys Polyflow can calculate the viscous and wall friction heating even if it has been neglected in the main nonisothermal flow problem.
The procedure for specifying the calculation of viscous and wall friction heating is as follows:
Create a new sub-task.
Create a sub-task
Select Postprocessor as the sub-task type.
Postprocessor
When prompted, enter a name for the postprocessor sub-task.
In the F.E.M. Task Postprocessor menu, select Viscous (+ Wall friction) heating.
Viscous (+ Wall friction) heating
Ansys Polydata will tell you where the calculation will be performed. You can click to continue.
No additional parameters or boundary conditions are required, since the viscosity law is the same as that for the flow problem (which must be of the generalized Newtonian type).