Computational fluid dynamics (CFD) uses computer simulations to model and analyze fluid flow problems. CFD allows researchers to create detailed 3D models of flow areas and calculate flow properties without physical experiments. The simulations solve the governing equations of fluid dynamics numerically and output results that can be visualized, like pressure distributions and flow velocities within complex objects like compressors and turbines. Examples show how CFD was used to analyze and improve the internal flow of systems such as a radial compressor and supersonic turbine nozzle.

1. Computational Fluid Dynamics –
CFD
Research into fluid dynamics does not always require experimental apparatus. The flow field can
be simulated on a computer using computational fluid dynamics, or CFD.
In many cases, the image of the flow field is much more detailed than one that would be possible
to achieve through taking measurements.
The concept is similar to principles used in strength analysis using the Finite Element Method
(FEM).
Steps in Computational Fluid Dynamics
 3D model creation of the flow area
 Calculation grid creation for the flow area
 Definition of the starting values and boundary conditions
 Numerical solving of the flow equations
 Post-processing of the results, graphic visualisation, and evaluation
Fluid Dynamics Laboratory CFD Tools
 Finflo, a flow-solving programme created by the Helsinki University of Technology
 Fluent, a commercially available CFD calculation programme
 GridGen, a programme for grid creation and pre-processing
 IGG, a programme for grid generation and pre-processing
 Fieldview, a programme for post-processing and visualization
Examples of CFD simulations

2. The pressure distribution and power lines in
a radial compressor and bladed diffuser
The flow rate at different sections of a
centrifugal compressor's flow channel
Supersonic turbine stator nozzle

3. Original geometry, in which the flow is
unevenly accelerated during the CFD
simulation.
An improved version, which accelerates
steadily up to more than double the speed
of sound.