1. TransAT

ASCOMP GmbH software package TransAT (Transport phenomena Analysis Tool) can simulate a wide range of single and multi-fluid/component flows with heat transfer. TransAT is particularly dedicated to predicting fluid-fluid and fluid-solid multiphase flows (CMFD), featuring large density and viscosity ratios. Typical applications range from surface-tension dominated flows (microfluidics) to large-scale turbulent flows.

Specific features

  • Rapid gridding of complex geometry
  • Direct CAD import using STL files
  • Moving bodies, fluid-structure interaction

Its specific predictive capability and strength are is to transcend simple averaged modelling towards Large Eddy Simulation of turbulent flows and Interface tracking of practical multiphase flows.

The CMFD code TransAT© developed at ASCOMP GmbH is a multi-physics, finite-volume code based on solving single and multi-fluid Navier-Stokes equations. The code uses structured, multi-block meshes. MPI parallel based algorithm is used in connection with multi-blocking. The grid arrangement is collocated and can thus handle more easily curvilinear skewed grids. The solver is pressure based (Projection Type), corrected  for low-Mach number compressible flows. High-order time marching and convection schemes can be employed; up to third order Monotone schemes in space.

Multiphase flows are tackled using interface tracking techniques for both laminar and turbulent flows, where the flow is supposed to evolve as one fluid having variable material properties, which vary according to the colour function. Specifically, both the Level-Set and the Volume-of-Fluid methods can be employed. Static or dynamic angle treatment is possible. Turbulent multiphase flows can be tackled within both the RANS and LES frameworks, with specific near interface treatments.

Specific advantages

  • Fast, innovative meshing technology based on IST (Immersed Surfaces Technology)
  • Automated grid refinement of boundary layers using BMR (Block Mesh Refinement)
  • A very high meshing efficiency rate is obtained with IST/BMR, up to 75% in 3D.
  • Highly accurate numerical algorithms (2nd and 3rd order schemes)
  • Scalable parallelization using MPI and Open-MP; grid splitting for optimized load balance
  • Multi-block, multi-grid technology
  • TransAT© runs on Windows and Linux Platforms: 32 & 64 bits