[toanhkhoas1212]

Hello everyone,

I am currently working on a simulation of a stirred tank using a Rushton turbine in ANSYS Fluent. The tank contains glycerin (with a density of 1260 kg/m^3 and viscosity of 600 cP) up to 30 cm, while the total tank height is 42.5 cm with air above the glycerin. To model these two phases, I used the Volume of Fluid (VOF) approach.

For the impeller rotation, I employed the sliding mesh technique. To better observe the flow dynamics, I introduced PVC particles as tracers, which have a density of 1380 kg/m^3 and are located at the tank's bottom. These tracer particles are modeled in Fluent using the Discrete Phase Model (DPM) with a diameter of 3mm, a mesh size of 1mm, and physical models including Saffman lift force, virtual mass force, pressure gradient force, and stochastic collision.

I've set up the simulation with SIMPLE for pressure-velocity coupling, and for spatial discretization, I'm using PRESTO! for pressure and Second Order Upwind for momentum. The volume fraction is treated with the compressive scheme, and least squares cell-based method is used. For the DPM particle injection, I used a surface injection with 18,668 particles.

However, at 0.931 seconds into the simulation, I encounter a floating-point error, despite having good mesh quality (minimum orthogonal quality of 0.48 and maximum skewness of 0.48).

Has anyone encountered a similar issue or does anyone have suggestions on how to resolve this floating-point error?

Any help would be greatly appreciated!

Thank you.