Local Restriction (2P) Documentation

I have recently read the available documentation for the Simscape local restrictor component for two-phase (2P) flow (Link to documentation), and would like to learn more about the underying physics applied within the block.

My interest is in the momentum balance equations in particular, which have quite a unique form compared to what I have been able to find on my own, e.g., the 'kt' parameter for turbulent flow.

Can anyone provide an additional reference (or documentation) providing more context on these momentum balancing equations about the restrictor orifice?

Answer 1

[Prasanna]

Hi,

It sounds like you're aiming to get a deeper context into the physics that drive the Simscape local restrictor component, specifically in terms of two-phase (2P) flow and momentum balance.

The momentum balance equation is derived from first principles internally. Conceptually, the momentum balance equation in Local Restriction (2P) is derived from a control volume (CV) analysis, where we model the flow from the inlet to the restriction as a flow contraction and the flow from the restriction to the outlet as a flow expansion.

For the flow contraction from inlet to restriction R, the momentum balance is:

where is approximated as =

For the flow expansion from restriction R to outlet, the momentum balance is:

Integrating these equations with the defined velocities produces the equations utilized in the model. This approach is purely based on momentum balance analysis.