Mixing Time Studies Not Converging To Same Values
To whom it may concern,
Hello. My name is Ryan and I am a beginner user of ANSYS Fluent. I am running transient CFD simulations in ANSYS Fluent (a.k.a. mixing time studies), using previous Fluent files of steady state CFD simulations that have converged. These studies use a mesh created from a geometry I built in SpaceClaim. The geometry represents that of a bioreactor.
I am conducting these mixing studies essentially at 5 different agitation speeds (speed at which the impeller in the bioreactor revolves), since the previous steady state simulations were run at 5 different RPM's. In the mixing study simulations, a tracer is added into the tank and mixed throughout. The results display graphs showing the mass fraction of the flow (Vertex Average of Tracer) at various points, over time.
For the first three agitation speeds (66 RPM, 84 RPM, and 101 RPM), the Vertex Average of Tracer converges to 0.000985. However, at 107 RPM and 114 RPM, it converges to 0.0009909.
Do you know what may be causing the discrepancy in what number to which the results converge?
If there is any more information you need, please do let me know. Thank you in advance for your help.