The Reacting Pipe Flow (rpfl) interface (), found under the Chemical Species Transport branch () when adding a physics interface, is a multiphysics interface that combines the three physics interfaces: Pipe Flow, Heat Transfer in Pipes, and Transport of Diluted Species in Pipes. The physics interface approximates the flow profiles in pipes and channels by a 1D assumption on lines in 2D and 3D. Depending on additional add-on products, multiple species can be modeled.

When this physics interface is added, these default nodes are also added to the Model Builder — Fluid, Pipe Properties, Temperature, Pressure, Concentration, and Initial Values. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions and volume forces. You can also right-click Reacting Pipe Flow to select physics features from the context menu.

The Label is the default physics interface name.

The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first physics interface in the model) is rpfl.

Select a Fluid model — Newtonian (the default), Power law, Bingham, or Herschel-Bulkley.

Enter a Reference pressure level pref (SI unit: Pa). The default value is 1[atm].