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How to create a simulation of a water jet hitting an object

Question asked by Graham Rigby on Nov 26, 2015
Latest reply on Nov 29, 2015 by David Paulson

Hi. So I'm trying to simulate a pelton wheel turbine using SolidWorks flow simulation. I am only looking at one stationary bucket, just to measure that the forcing is accurate to the hand calculations. For those unfamiliar with the pelton wheel, essentially high pressure water is sent through a nozzle out into ambient air. This now fast moving jet of water is shot at a bucket which redirects the flow. The change in momentum of the water jet gives the bucket a force.

 

My issue is that I do not know how to go about this problem. I have the diameter and speed of the jet already from nozzle calculations. All I want is a jet of water flying through an air medium. The air actually isn't that important but I'm not sure if I can just have nothing there at all. I'm doing it in external flow. Usually what SolidWorks thinks I want is for this scenario to happen under water. Sure I have my jet of water going at 40 m/s, but it's carrying a lot of surrounding water with it. I can't figure out how to get the simulation to not care about the medium fluid and to just care about the water jet.

 

This is my test setup, a simple "nozzle" and a plate. Essentially I want a stream of water emanating from the face at the narrow end of the nozzle at 40 m/s directed at the plate. I then measure the force on the plate.

CFD setup.png

This is what I'm able to get. Notice the streamlines emanating from the far left, in addition to the ones given by the nozzle (hard to see but they're there at the correct speed).

CFD problem.png

I do not want there to be fluid anywhere else but the jet, or air if a medium is required. Any help? I am using SolidWorks 2015.

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