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Example 6: Flow Path with Multiple Inlets and Outlets

General

A flow path with multiple inlets and outlets is solved.
Forced inflow and forced outflow are set one each.
Natural inflow/outflow is set to the three areas where it is not determined whether the flow is incoming or outgoing.
Unless specified in the list below, the default conditions are applied.

Results will vary depending on Femtet version and the PC environment.

Analysis Space

Item	Setting
Analysis Space	3D
Model Unit	mm

Analysis Conditions

Item	Tab	Setting
Solver	Solver selection	Fluid Analysis [Bernoulli]
Analysis Type	Fluid Analysis	Steady-state Analysis
Meshing Setup	Mesh	General Mesh Size: 5 [mm]

Model

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
6/Solid	Flow_path	100_Water *

* Available from the material DB

Boundary Condition

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Setting
In_1/Face	Fluid	Inlet	Forced Inflow Flow Velocity Specified: 0.1 [m/s]
Out_1/Face	Fluid	Outlet	Forced Outflow Pressure Specified: -1 [Pa]
Inout_1/Face	Fluid	Inlet/Outlet	Natural Inflow/Outflow
Inout_2/Face	Fluid	Inlet/Outlet	Natural Inflow/Outflow
Inout_3/Face	Fluid	Inlet/Outlet	Natural Inflow/Outflow

Results

The vectors of the flow velocity are shown below.

The vectors are adjusted to the same length in the graphics setup.

Before the analysis, flow directions were unknown at three faces.
Inout1_1 has a flow in the inflow direction and Inout_2 and Inout_3 have flows in the outflow direction.

The table of the volumetric flow rate is shown as follows.

The inflow rate is shown in the positive value and the outflow rate in the negative values.

The sum of Inout_1 and In_1 gives the inflow rate of 11e-5 [m3/s] and
the sum of Inout_2 and Inout_3 and Out_1 gives the outflow rate of 4.15e-5 [m3/s].
The inflow and outflow rates are nearly balanced.