Perhaps the most useful improvements to es-ice is the addition of more engine specific simulation settings, case details, and results into the report summary. Users are also able to export this report into Excel where the automation is improved using embedded Excel driven scripts. This allows for the sector simulation processes, plotting, and results animation to all be performed within Excel.
Other es-ice improvements include:
- Automatic mesher for cylinder models
- Trimmed half model reflections for symmetric meshing
The new release also comes with improvements to the ECFM-CLEH models. The library will now allow the use of multi-component fuels, dual-fuel engines, and oxygenated fuels to assess the effects of the complex combustion chemistry.
Additional library improvements contain:
- User specific fuel chemistry libraries (for laminar flame speed, autoignition, or equilibrium)
- Use of equivalence ratio over mixture fraction for increased accuracy
- Additional equivalence ratio, pressure and EGR dimensions to test more engine operation conditions
Improvements to other models can also be seen in the new release. For instance, the higher-order MARS differencing scheme for the NORA NOx and soot models is improved while clocking in with a similar computation time. Additionally, this soot sectional method, is now able to function with every ECFM and PVM-MF combustion model.
The PVM-MF (Progress Variable Model – Multi-Fuel) model, has also seen advances. The PVM-MF is designed to model detailed combustion chemistry under small Damkohler number conditions. This is often seen in lean, rich or high EGR engine operating conditions. This model has seen the improvements to fuel libraries including diesel, gasoline, and natural-gas. The model also now includes a library on natural-gas–diesel (dual fuel) and is able to support user defined chemistry mechanisms or fuel libraries.
The new release has also seen changes to the Raoult’s Law multicomponent model. This model will see improved simulations of the evaporation of ethanol-gasoline mixtures. Essentially, the STAR-CD UNIFAC models can better represent fuel mixtures with varying molecular structures like that of bio-fuels.
STAR-CD’s new release sees a new heat transfer option. This option will provide easier calculations of crank-angle resolved changes within structural temperature as well as the effect in-cylinder processes on the calculation. This will improve spray-wall impingement during combustion and at thermally insulating layers. This new model assumes a 1-dimensional heat transfer locally within the structure. This is then solved using many 1-dimensional meshes which are normal to the surface. The model can handle multiple material/layers, and contact resistance on each major components. Boundary layers for this model can be user specified or mapped using a cycle-averaged structural solution.
Other STAR-CD v4.22 developments in the new release are as follows:
- Proper Orthogonal Decomposition (POD) for quantitative analysis of LES calculations for the comparison of nominally cyclically-repeating flow modes
- Enhanced Werner-Wengle wall model to include the SGS viscosity effects in fully turbulent regions at the wall boundary layer for a more accurate wall friction factor
- Enhanced discretization of the strain-rate for better small-scale dissipation.
Source CD-adapco.