Computational Fluid Dynamics Software Capabilities – AxCFD

Introduction

Once the preliminary and detailed design of a turbomachine has been done it is good practice to check the performance and flow behavior using more accurate models before setting off to manufacturing and testing which are quite expensive; this is usually where computational fluid dynamics (CFD)  comes in.

AxCFD^® enables the running of full 3D RANS computational fluid dynamics in turbomachinery channels for single rows, individual stages or full machine including elements like ducts, etc.

Pre-Processing

Thanks to the integrated architecture of the AxSTREAM^® software platform geometries, boundary conditions, clearance values, number of blades, rotation speed, etc. are automatically inherited from the AxSTREAM^® project which significantly simplifies and reduces the pre-processing setup time while preventing human errors. These can however be edited as desired to study different effects. In a similar way periodicity conditions as well as inlet and outlet surfaces are automatically created based on the geometry from the AxSTREAM^® project.

An automated turbomachinery-specific, structured hexagonal meshing by customizable blocs is available for computational domain division. Different types of mesh generation are available and can be refined in each direction, in the boundary layer, in blocs, etc. and rotation zones. Location of cooling holes can be set up as well.

Solvers

Different problem formulations are available depending on whether the user desires to calculate a pressure value (inlet or outlet) or the machine mass flow rate. Viscosity and different turbulence models (including k-ε, k-ω, k-ε RNG, k-ω SST)  can be used for new calculations or to resume existing ones. Heat transfer between the blades and the fluid can be accounted for along with the material surface roughness. Each computation can be run for a given spanwise location (radial section), for an axisymmetric sliceor for the entire 3D geometry.

Post-processing

Once the calculation is converged visualization of contours of pressure, temperature, velocity, Mach number, etc. is possible at any location within the channels through customizable post-processing spanwise and streamwise sections. Additionally, blade loading for any radial location can also be displayed.

Finally, export of CFD results allows comparisons at design and off-design conditions between different calculations using the same or different solvers (1D, 2D, 3D) as well as experimental results.

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