Nowadays, the improved performance of modern computers means flow-related problems can increasingly be resolved by computer. Modern CFD (computational fluid dynamics) software enables us to find solutions to flow-based problems while taking heat exchange, chemical reactions and other physical models into account. If we consider the measurement errors that can arise during metrology, then CFD simulations are a real alternative or enhancement to conventional forms of measurement.
In cooperation with the Wildau University of Applied Sciences, ERK has gained extensive experience in the calculation of various types of boilers.
Which flow problems can be resolved with CFD?
- continuous and discontinuous flows
- incompressible or compressible flows
- laminar and turbulent flows, in which various turbulence models can be used
- heat exchange through conduction, convection and radiation
- mixing processes
- chemical reactions (e.g. incineration/combustion)
- production of NOx and soot
- multi-phase flow (gas/liquid, gas/solid, liquid/gas)
- phase change (melting, evaporation/vaporisation, congealment)
- translational and rotational geometries
- clear, unobstructed surfaces
Four points affecting the complexity of CFD simulations
- Geometric complexity. The more complex the boundaries become, the more difficult it is to use the CAD system and to design the grid, in particular.
- Size of the gradients. The larger the gradients, the harder it is to adjust the grid (local compression is needed).
- Number of physical models. As the number of physical models increases, so does the complexity of generating and calculating them.
- Number of grid cells. The greater the number of cells, the more complex the calculation becomes.
What does the calculation accuracy of a CFD simulation depend on?
- close conformity of the defined boundary conditions with actual conditions
- choice of grid structure
- quality and number of the individual cells
- selected calculation models