This involves modeling the transient process of the airflow in the cylinder, typically with the objective of maximizing the trapped air mass and examining the bulk motion (swirl and tumble) that this flow induces. This is all before we start layering on complex physics models when we start to include fuel injection (Lagrangian spray, droplet-wall interactions, wall films) and combustion (ignition, flame propagation, emissions formation, knock).įor this reason, a lot of simulation performed early in the development process is concentrated on so-called “cold-flow”. The combination of high-speed flows, mesh motion requiring an EXTREMELY high level of mass conservation, and very small time scales (fractions of a crank-angle degree typically require time steps on the order of 1e-006 ) means a lot of work goes into the setup and the numerics must be carefully selected to accomplish stable runs with reasonable turn-around times.
This morph-map approach has been extensively tested and is highly conservative of mass for all practical applications.Īny in-cylinder simulation is among the most complex CFD simulations you can perform. The user has complete control over the mesh setup and can add additional regions of refinement (such as around a spark plug) as required.
This is done automatically for every simulation and does not require manual intervention by the user. The mesh is automatically refined in critical areas in line with best-practice: around the valve, the valve seat, the valve throat, up into the ports and around the gasket gap. STAR-ICE performs quality checks on the mesh as it morphs, automatically creating a new undistorted mesh when necessary and mapping the simulation results to it. All of the mesh movement is automatically taken care of by STAR-ICE, which automatically morphs and maps the mesh to account for the movement of the piston and valves. You only need to create a single initial mesh (comprising of trimmed cells and prism layers to capture boundary layer flow features).
STAR-ICE employs a simulation driver to run a transient mesh motion process. From fast setup of typical multi-hole injectors which can easily be customized for spray targeting, to quick selection of fuels, to automatic setup of common post-processing outputs like liquid and vapour penetration plots and fuel mass tracking, STAR-ICE has been designed to make the simulation setup easy and allow engineers to derive the most value of out the simulation process. STAR-ICE has been specifically developed to make setup quick and easy and leave time for the analyst to spend on “engineering” the solution rather than setting up the problem with lots of mouse miles and button clicks.
However, expert users can use STAR-ICE simulations as the starting point for performing more complicated multiphysics engine simulations that exploit the full range of Simcenter STAR-CCM+ simulation capabilities. You do not have to be an expert Simcenter STAR-CCM+ user to set up and run in-cylinder simulations using STAR-ICE as it uses an application-specific workflow and simplified interface. STAR-ICE opens up a minimal interface which shows only those inputs required for setting up an in-cylinder simulation, presenting a “top-down” workflow (you start at the top and work your way down through various levels).