CFD as a tool to create better products faster

By 16.8.2019

Project participants

  • Project owner and initiator: Outotec®
  • Additive manufacturing consulting: Layermetal
  • CFD analysis: Stressfield

Background

A while back Stressfield had the opportunity to be part of a project with the goal of creating an as efficient mixing nozzle as possible. The simplest way of adding chemicals to a process pipeline is via a T-type pipe fitting. However, that will not achieve a very efficient mixing and depending on the process needs, it could lead to subpar performance or an unnecessary high need of process chemicals. In the present project, the target was to achieve a uniform mixing of chemicals in the main process line within the shortest possible distance.

Project

Already from the project start, it was decided that the nozzle will be manufactured using additive manufacturing, or 3D printing. This gave essentially complete freedom regarding the nozzle geometry as no consideration to traditional manufacturing constraints had to be taken. As such, the nozzle geometry could freely be modified as seen necessary based on the CFD results. During the project, the nozzle geometry changed significantly as can be seen from the nozzle evolution in the Figure below.

Analysis plan

  • Analysis type:    Steady state
  • Turbulence:        k-epsilon realizable turbulence model
  • Multiphase:        Mixture or Eulerian multiphase model case dependently
  • Gravity:               On
  • Heat transfer:    Not considered
  • Solver:                 Ansys Fluent

Results

With the final nozzle design, the mixing could be radically improved. In fact, field measurements showed that the use of chemicals could be reduced by 40% from the baseline and a remarkably even mixing was achieved within only a few pipe diameters downstream of the mixing nozzle. See Figure below for contours of chemical concentration per surface area of solid particles in the main process line.

Contours of chemical concentration per surface area of solid particles

Further reading

Read more about how the Outotec Rapid Mixer improves the process results in process water recycling plants.