[Julian121]

Does static entropy show entropy generation (ds) or just entropy (s) in CFD post?

I have used the default zero reference specific entropy, but the static entropy contrours are all negative values. Is it correct?

[Opaque]

Values of Static Entropy themselves are irrelevant since they depend on the specified reference value. Same issue for Static Enthalpy.

They are only useful to compute changes of entropy, and you should use them that way.

The value reported in CFD-Post is just the property evaluated at (P,T) obtained from the solution. Ansys CFX is not solving a transport equation for the "conservation of entropy" if that was your line of question.

[Julian121]

I am solving a cfd problem in which I need to find the sources of efficiency loss and entropy production in an operating condition.

Is there another way to estimate entropy rise as static entropy is irrevalent?

[Opaque]

It seems that I did not express myself clearly.

The level value of Static Entropy is irrelevant, the delta of Static Entropy between inlet and outlet IS VERY relevant. Once you compute the delta, the reference value becomes irrelevant; therefore, it is arbitrary.

Write your "conservation of entropy" equation, and you will see what you need to compute to determine if the 2nd law is being satisfied.

Let take an example, two parallel plates, inlet, outlet, and adiabatic walls, what do you think the following represents

massFlowInt(Static Entropy)@Inlet - massFlowInt(Static Entropy)@Outlet

Write your 2nd law for an open system in stationary conditions, and you will see where this is going

[Levi8]

Hi,

I'm working on a multistage pump which has rotary and stationary domains.

I set a (frozen rotor) interface between a rotary and stationary where it can calculate the pressure by massflowAve(Total pressure in Stn frame)@ side 1 and massflowAve(Total pressure in Stn frame)@ side 2.

The problem is that the pressures on both sides aren't equal and their difference is more than 30%.

Thank you for your help.