Simulation of Water Turbine with CFX

hydroturbines · July 23, 2014, 16:58

Hello everyone,

I am working on simulation of a water turbine with CFX.
This is my first work in CFD.
Type of turbine: Francis (radial runner).

I have all the measured data in real turbine (net head, flow and output power).

My doubt is:
What are the best boundary conditions for inlet and outlet ?

Example:
Inlet Conditions: flow
Outlet Conditions: pressure

or
Inlet Conditions: pressure
Outlet Conditions: pressure

I do not know with is the boundary conditions that ensures better results in simulation for efficiency and cavitation.

Please, help me, every reply would be appreciated.

Thank you very much.

maximilianomavica · November 12, 2024, 09:42

you should use velocity for inlet and pressure for outlet,.

zacko · November 18, 2024, 02:18

There is a good guideline for Turbomachinery on that forum regarding Setups. To understand the various BC in CFX, have a look into the documentation.

To evaluate cavitation, an pressure outlet BC can be used, to vary the downstream pressure.

July 23, 2014, 16:58	Simulation of Water Turbine with CFX	#1
hydroturbines New Member Julio Duarte Join Date: Feb 2014 Posts: 2 Rep Power: 0	Hello everyone, I am working on simulation of a water turbine with CFX. This is my first work in CFD. Type of turbine: Francis (radial runner). I have all the measured data in real turbine (net head, flow and output power). My doubt is: What are the best boundary conditions for inlet and outlet ? Example: Inlet Conditions: flow Outlet Conditions: pressure or Inlet Conditions: pressure Outlet Conditions: pressure I do not know with is the boundary conditions that ensures better results in simulation for efficiency and cavitation. Please, help me, every reply would be appreciated. Thank you very much.

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November 12, 2024, 09:42		#2
maximilianomavica New Member maximiliano Join Date: Jun 2020 Posts: 18 Rep Power: 6	you should use velocity for inlet and pressure for outlet,.

November 18, 2024, 02:18		#3
zacko Senior Member Daniel Join Date: Feb 2017 Location: Germany Posts: 169 Rep Power: 9	There is a good guideline for Turbomachinery on that forum regarding Setups. To understand the various BC in CFX, have a look into the documentation. To evaluate cavitation, an pressure outlet BC can be used, to vary the downstream pressure.