Building Solvable Models

Every FlowDesigner model needs three essential elements to solve:

Inlet Boundary

This defines your fluid properties and temperature reference using either:

• Assigned Flow

• Assigned Pressure

• Reservoir

FlowDesigner automatically identifies the inlet based on:

• Relative elevations between nodes

• Pressure differences

• Flow direction settings

• Position relative to boosters or control valves

Pipe and Nodes

Components that represent the equipment existing between the two boundaries.

Outlet Boundary

Define where your fluid exits the system using any boundary node. For Assigned Pressure or Reservoir outlets, fluid properties only affect the total outlet pressure calculation.

Flow Designer hydraulic models should have a complete representation. If any of these items is missing, the solver will not converge:

• Inlet Boundary

• Pipe and In-between nodes

• Outlet Boundary

Inlet Boundary

The inlet boundary is the source of fluid property data and temperature reference for the calculation process. This can be represented in the model as either an Assigned Flow, Pressure or Reservoir node for a system.

The solver automatically determines which will be the inlet boundary component based on its configuration to drive flow from the node such as:

• Boundary’s relative elevation with other nodes

• Boundary’s relative pressure with other nodes

• Boundary’s relative elevation and pressure with other nodes

• Setting Assigned Flow Node direction to “Into Network”

• Relative location of the boundary towards a booster / flow control valve inlet

Pipes and in-between nodes

Pipes and in-between nodes can be any of the modelling components that connects the inlet and outlet boundary.

Outlet Boundary

The outlet boundary on the other hand, serves as either the flow or pressure basis for the fluid destination. It can be represented by any boundary node in the component toolbar.

Take note that when an Assigned pressure or Reservoir node is applied as outlet boundary, the fluid definition in the node is only used for determining total outlet boundary pressure.