The inletOutlet boundary condition is normally the same as zeroGradient, but it switches to fixedValue if the velocity vector next to the boundary aims inside the domain (backward flow). The value of that fixedValue is inletValue. See figure ().
Figure: The meaning of inletOutlet boundary condition
U:
boundaryField
{
".*_outlet"
{
type inletOutlet;
value $internalField;
inletValue uniform (0 0 0);
}
}
k, omega, epsilon, T:
boundaryField
{
".*_outlet"
{
type inletOutlet;
value $internalField;
inletValue uniform 0;
}
}
The pump efficiency can be evaluated using following efficiency formula:
(6.3)
where denotes the efficiency, is the torque, is the angular velocity, is the volume flow rate and is the specific enthalpy which can be evaluated as follows:
(6.4)
Subscript in means averaged quantities at the inlet, whereas subscript out denotes averaged quantities at the outlet. The evaluation of pump efficiency for different patches is also possible.