Computational Fluid Dynamics

Computational Fluid Dynamics is a revolutionary modern form of software, which numerically simulates fluid flow over a virtual geometry. Until recently, CFD has only been effectively utilised within the aerospace and automotive industries due to high software costs and powerful computational requirements. With the development of very fast PC’s it is now possible to run the majority of CFD models on a desktop.

Not only is CFD a cost-effective method of numerical simulation, it also creates a visual perspective (colour images) of the flow of a naturally indistinguishable (ie. invisible) fluid. By creating either a 2D or 3D model of the object (virtual prototype) on a PC, CFD analysis can enable the object to be transported straight through to prototype stage with speed and efficiency, without the lengthy testing costs and development time for experiments.

Our consultants at e3k are highly trained and qualified in CFD, with capabilities which include particle tracking, turbulence modelling, heat transfer, compressible flows, acoustics and combustion reactions. e3k primarily uses the CFD package "FLUENT" by Fluent Inc. of the US.

The Process:

Essentially, CFD involves the following steps:

1. Generation of the virtual model (a drawing of the object in the computer), often including importation of existing CAD data and geometry simplification

2. Discretisation or meshing (forming smaller volumes from the overall volumes involved)

3. Setting of boundary conditions (eg. inlets, sources of momentum, heat etc.)

4. Iterative solution of the relevant mathematical equations governing the flow (continuity, energy, momentum etc.)

5. Plotting of raw data and reporting of required variables (eg. velocity, temperature, pressure, turbulence)

Output from the modelling can be presented numerically in tables and/or graphically as x-y type plots, graphs or sectional 3D colour prints of contours, vectors, streamlines, and particle trajectories.

Scope of Modelling Available:

Fluid flows can be modelled in steady state or as unsteady transient flows (ie flow over time), in or around stationary or rotating geometry.

The types of fluid flows that can be modelled include:

Liquid
Gas
Granular flows
Slurry flows
Combinations of fluids

The types of physical parameters that can be modelled and obtained from CFD include:

Standard flow parameters for any gas or liquid (velocity, pressure)
Energy (temperature)
Turbulence
Compressibility
Gaseous species
Chemical reactions eg combustion
Discrete phases (particle tracking, evaporating/combusting droplets)
Radiation
Free surfaces flows (eg. flow about a ships hull, droplet formation)
Mixing

Computational Fluid Dynamics or CFD is a very useful design tool. It involves numerically simulating complex fluid flow phenomenon. Until recently, CFD has been only effectively utilised within the aerospace and automotive industries due to prohibitive software costs and powerful computational requirements. With the development of very fast PCs it is now possible to run CFD models effectively on a desktop.

Computer modelling of fluid or gas flows has the potential to reduce development time and remove the need for laborious and lengthy wind or water tunnel experiments. Gilmore Engineers has upgraded its CFD capabilities to include particle tracking, and the modelling of turbulence, heat transfer, compressible flows and combustion reactions. Some recent applications have included modelling the air flow over a prime mover spoiler, and particle trajectories about a centrifugal-type fan.

Click here for selected CFD case studies conducted by e3k

Click here for a CFD Brochure