Hello everyone.

I’m trying to replicate some experimental analysis with Ansys Fluent. Particularly I’m trying to simulate a Wells turbine on different airflow conditions (same RPM, different inlet velocities).
The goal is to plot torque and pressure coefficients over time/flow coefficient.
I’m getting very bad torque values, about 50% of the experimental results (more on that below).

Here’s the setup:

I created a CAD with same exact geometry features of the tested turbine.

I imported it into Ansys, considered just the duct in which the air flows (just like the OWC simulator in the real test). Divided the domain into 3 zones, two stationary and 1 MRF. (I considered no tip gap to avoid strange behavior there, since 1mm of gap it could be hard to simulate). Also, only simulated 1/6 of the turbine, a single blade passage (6 blades in tot)

Meshed and open fluent.

The solver is Ansys Fluent, I set up the air conditions (viscosity and density). I set up the MRF rotational speed and inlet velocity on 9m/s (i want to get one condition right before analyzing more intel speed values). Used k omega.

I initialized and run 500/1000 iterations.

Data obtained:

CFD (Torque on a single blade):

Pressure: 0.016280575 Nm
Viscous: 0.0025203426 Nm
Total: 0.018800917 Nm

Experimental results at 65Hz and 9m/s of inlet speed vel:

0.206 Nm, which divided by 6 give me: 0.0343 Nm

That's about 54% of the exp data

Thanks everyone:)

I’ve just got my first potential customer, and I’m willing to compromise on the money for some brand visibility. I wonder generally what’s the pay?

They have a small electronics box and want to run the analysis on it.

I’m an employed fresher engineer with a BSc in Mech engineering if this is relevant

Hi, I'm quite new to CFD and I'm having major problems with meshing. I'm studying the drag coefficient on an elliptical and tangent ogive nose cone and I'm using a 2D axisymmetric geometry. From what I read on literature it's important to have y+ close to 1 on the first layer near the wall, because with this setup the model (k-omega SST in this case) doesn't need to use wall functions. I don't understand from what criteria I need to subdivide the edges or what element size to use to have an accettable mesh; then in ansys meshing if I use a general mesh element size to small (and I don't know what is too small for it) the meshing process get's stuck at 5% when converting triangular elements to quads. Is there any literature, videos or piece of knowledge I should read or watch to really understand meshing? I feel like I'm walking in the dark. If needed I will upload the domain I was trying to mesh.