KRONOSPAN is the global leader in the production of particleboards, MDF (Medium Density Fibreboard), laminate flooring and UF/MUF/MF resins for wood-based panels. It is one of the fastest growing enterprises in woodworking industry worldwide and located in 22 European countries, USA and China. The group’s revenue reaches 4 billion $ (2015).

In several production stages of the company, a batch reactor is utilized in order to mix liquids and solids that are used at the manufacturing process. KRONOSPAN decided to design a larger reactor, which will come from the scaling up of an existing one that operates satisfactorily in several production sites. However, intense heat generation and viscosity changes are sometimes exhibited in a number of production stages. So, it was decided to firstly create a CFD model in order to verify the proper functioning of the new reactor prior to manufacturing.

This consulting project was assigned to SIMTEC. The purpose of the CFD study was to verify that the new scaled-up reactor will still provide efficient mixing and heat transfer, which are very crucial not only for high output and quality of the product but also to avoid off-limit conditions that may range from discarding the batch to completely destroying the reactor due to content solidification (run-off).

The 3D solid geometric model was imported into ANSYS DesignModeler for processing. Next, the computational mesh was constructed (ANSYS Meshing) needed for the simulation process. The CFD solution leveraged an appropriate turbulence model of the Reynolds-Stress family, capable of capturing the flow characteristics, especially the swirl effect caused by the impellers rotation. The later was prescribed by the Multiple Reference Frame (akaFrozen Rotor) algorithm. Fig. 1 shows the velocity magnitude in various planes inside the reactor. Simulation results confirmed the efficiency of the new design in terms of rapid and sufficient mixing rates, which guarantee the intended thermo-chemical performance of the design.