A mass transport option is available for the current-technology elements, SOLID278 and PLANE292, and the legacy elements, PLANE55 and SOLID70, to simulate the mass transport of heat by a flow with a prescribed velocity field in your analysis.
The table below lists the KEYOPT values you must set to include the mass transport option, the command you issue to specify the velocity components of the flow field, and whether or not the element is restricted to the condition that the element Peclet number (Pe) is less than 1. There is no restriction on the element Peclet number for the current-technology elements PLANE292 and SOLID278, and they offer numerical tools that enable convergence for high Pe conditions (for details, see Streamline Upwind Petrov-Galerkin (SUPG) Formulation).
Table 4.1: Specifications for Including Mass Transport in an Analysis
| KEYOPT to Include Mass Transport[a] | Command to Specify Velocity Components in Equation 6–1 in the Theory Reference | Pe Restriction[b] | |
| Current-Technology Elements | |||
| SOLID278 | KEYOPT(11) = 1, Dflux Neumann boundary condition[c]
KEYOPT(11) = 2, Tflux Neumann boundary condition[c] | BF,,VELO,VX,VY,VZ | no restriction |
| PLANE292 | KEYOPT(8) = 1, Dflux Neumann boundary condition[d]
KEYOPT(8) = 2, Tflux Neumann boundary condition[d] | BF,,VELO,VX,VY | no restriction |
| Legacy Elements | |||
| PLANE55 | KEYOPT(8) > 0, Dflux Neumann boundary condition | R,,VX,VY | Pe<1 |
| SOLID70 | KEYOPT(8) > 0, Dflux Neumann boundary condition | R,,VX,VY,VZ | Pe<1 |
[a] Dflux and Tflux Neumann boundary conditions are described in Diffusive Flux and Total Flux Neumann Boundary Conditions in the Theory Reference
[b] For details, see Streamline Upwind Petrov-Galerkin (SUPG) Formulation.
[c] Do not create models that have some elements with a value of 1 and others with a value of 2 for KEYOPT(11). On the other hand, it is possible to have combinations of elements with KEYOPT(11) = 0 and 2 as well as KEYOPT(11) = 0 and 1 in the same model.
[d] Do not create models that have some elements with a value of 1 and others with a value of 2 for KEYOPT(8). On the other hand, it is possible to have combinations of elements with KEYOPT(8) = 0 and 2 as well as KEYOPT(8) = 0 and 1 in the same model.
While the legacy elements are limited by the condition that the element Peclet number is less than one, there is no such limitation for SOLID278 and PLANE292, as is described in the next section. The discussion also details how to activate the Streamline Upwind Petrov-Galerkin Formulation and one of the three discontinuity capturing (DC) terms to smooth spurious oscillations if they occur for high Peclet number flows using SOLID278 or PLANE292 elements.
For a discussion of the theory and underlying governing equations for mass transport, see Mass Transport (Advection) in the Theory Reference. Further details are given in the individual element descriptions in the Element Reference .