The Inlet node adds a boundary condition for the inflow (or outflow) perpendicular (normal) to the boundary. It has three options that can be used to specify inlet condition on a boundary, as follows:
Enter a value or expression for the Normal inflow velocity U0 (SI unit: m/s). A positive value of
U0 represents an inflow velocity. A negative value represents an outflow velocity. The inlet velocity boundary condition is implemented as;
where U0 is a value or expression for the specified inward (or outward) Darcy velocity. A positive value of the velocity
U0 corresponds to flow into the model domain whereas a negative value represents an outflow.
D is the elevation head which is set to zero for other than Subsurface Flow Module applications.
Use the Pressure option to specify the inlet pressure on a boundary. In many cases the distribution of pressure is known, giving a Dirichlet condition
p =
p0 where
p0 is a known pressure given as a number, a distribution, or an expression involving time,
t, for example. Enter a value or expression for the
Pressure p0 (SI unit: Pa).
If you select Mass flow as the inlet condition, there are four options to specify the
Mass flow type: the total
Mass flow rate M0 (SI unit: kg/s), the
Pointwise mass flux N0 (kg/(m
2·s)), the
Standard flow rate Qsv (m
3/s), and the
Standard flow rate Qsccm (in number of SCCM units).
With the options Mass flow rate,
Standard flow rate, and
Standard flow rate SCCM, positive values correspond to flow into the model domain:
where M0 is a value or expression for the specified inward (or outward) Darcy flux.
For the Standard flow rate Qsv, which is a volumetric flow rate of a gas at standard density according to the SEMI standard E12-0303, the equation above is divided by the standard density term:
ρstd can be specified as mean molar mass
mm divided by a standard molar volume
Vm, or as a function of standard pressure
pst and standard temperature
Tst:
The Standard flow rate SCCM option is equivalent to the Standard flow rate option, except that the flow rate is entered directly in SCCMs (standard cubic centimeters per minute) without the requirement to specify units. Here, the dimensionless number of SCCM units
Qsccm should be specified.
In the Pointwise mass flux boundary condition, positive values correspond to flow into the model domain:
where N0 is a value or expression for the specified inward (or outward) Darcy flux.
) and select Advanced Physics Options in the Show More Options dialog.