{"id":407351,"date":"2025-01-28T09:29:10","date_gmt":"2025-01-28T09:29:10","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/modelling-mixing-with-tracer-for-stirred-tank-with-free-surfacevortex\/"},"modified":"2025-01-28T09:29:10","modified_gmt":"2025-01-28T09:29:10","slug":"modelling-mixing-with-tracer-for-stirred-tank-with-free-surfacevortex","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/modelling-mixing-with-tracer-for-stirred-tank-with-free-surfacevortex\/","title":{"rendered":"Modelling Mixing With Tracer For Stirred Tank With Free Surface\/Vortex"},"content":{"rendered":"

<p>Hi,<\/p><p>I have been attempting to model batch mixing with a tracer in a unbaffled stirred tank, where the free surface of the liquid deforms leading to a vortex.<\/p><p>To begin with I have modelled the hydrodynamics for the gas-liquid system (air-water) using the homogeneous VOF solver and SST K-Omega Curvature Correction model.<\/p><p>Once I have got a converged solution, I switched off all the flow & turbulence equations and activated the species transport equation, so the system is now gas-binary liquid (air-water tracer). I have defined the properties of the tracer liquid as the same as the bulk liquid (water) as I assume there is no significant change to the flow behaviour with the introduction of tracer material. I have defined the diffusivity between water and tracer as 1.473*10^-9 m^2\/s as per literature reports. I have also approximated the volume of tracer by patching an appropriate number of cells in the mesh.<\/p><p>The injection position is the free surface of the liquid (0.2 cm from the wall) where the mixing is performed in batch (no inlets or outlets). An image of the initial conditions are provided below for context<\/p><p><\/p><p>What I am noticing is that throughout the course of the simulation, the tracer mass fraction contour appears to give a value of 0 in the domain:<\/p><p><\/p><p><\/p><p>Also my concentration plots don’t make sense<\/p><p><\/p><p>I have ran the same simulation single phase (assuming flat liquid surface) which makes more sense:<\/p><p><\/p><p><\/p><p>I don’t understand why applying the same methodology for mixing with a flat liquid surface has failed to work when considering a vortex. No one appears to have performed such a simulation before (all attempts ofr mixing have been with flat liquid surface). Are there any possible suggestions on where to proceed next?<\/p><\/p>\n","protected":false},"template":"","class_list":["post-407351","topic","type-topic","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t