Using a centrifugal pump in a two-phase (2P) fluid in Simscape

I want to analyze a steam generation process from a controls point of view and for that I am studying Fluid Vaporization in Pipe example from Mathworks website.

I am specifically interested in the mass flowrate and pressure downstream of the pump. The source blocks inside the two-phase fluid library are not giving good results as they are ideal sources. So I want to use a centrifugal pump (CP) with parametrization, which will give me pressure and flowrate w.r.t. to the pump rpm, just like an actual system.

The problem is simscape does not allow me to mix two different media which I totally understand. But it is strange that they not provide a CP block for a water-steam system where the pump comes into contact with the water only. Can anyone please guide me, what are my options here? How can I achieve the simulation with a CP.

I was thinking that I will write my own CP block for the two phase system but unlike other blocks the source code for the CP is hidden from users. And with no background in fluid dynamics I cannot make a CP block from scratch. Is there any easy way to achieve this?

Can I make a parameterized CP by combining existing two-phase fluid blocks?

Is there any way to interface a CP with a two phase fluid system?

And why is Mathworks not providing such basic blocks? Is it just missing from there library or is there some reason for not having this block. I mean is it impossible to stimulate a two phase system with a centrifugal pump because of possible two states of a fluid?

Answer 1

[Yifeng Tang]

It's possible to build a model for CP to reproduce much of its behavior. If you can build a 2D table from reference data for the flowrate as a function of RPM and pressure difference (head, pressure ratio, etc.), you can implement this table in Simscape to drive a controlled mass flowrate source. In this example: https://www.mathworks.com/help/hydro/ug/sscfluids_ev_thermal_management.html, the compressor is modeled using such an approach. In case of a pump, where you may be able to assume the density doesn't vary much, you can potentially simplify it by removing the non-dimensionalization with reference pressure and temperature, so the model is simpler.

Another possibility is to use the Centrifugal Pump (TL) block and the TL-2P interface. If you are working with water, this may work just fine, as the default fluids for TL and 2P are both water. The limitations of the TL-2P interface still apply though.

https://www.mathworks.com/help/hydro/ref/centrifugalpumptl.html

https://www.mathworks.com/help/hydro/ref/interface2ptl.html