Simulation Software for Fluids and SolidsSimulation Blow Molding Plastic Tank
Figure 1: CAD model created in NOGRID's COMPASS
Figure 2: Initial extruded flat parison with variable thickness distribution in full 3-D (no shell elements)
Figure 3: Extrusion blow molding process in full 3-D (no shell elements) using a flat parison with variable thickness
Figure 4: Animation of the extrusion blow molding process in full 3-D
Simulation of blow molding of plastic tanks using our meshless CFD software NOGRID points will move you into the world of 3D simulations. Based on the geometrical model which can either be imported from your CAD or created with our CAD preprocessor COMPASS you can generate a computer model of a tank in a very short time compared to mesh-based methods.
Figure 1 on the left side shows a geometry built in COMPASS. To use the geometry within the fluid simulation (only) the walls need to be meshed. For 3D simulations this is a surface mesh and for 2D simulations it is a line mesh. The meshing can be done in COMPASS using also enhanced features like for instance the mesh collapsing technique.
Understanding blow molding processes
Fuel tanks made by plastics allow for weight reduction and high accuracy in comparison to steel tanks and they are free in design to fit into given space. The blow molding allows to produce tanks with complex geometry. The challenges are the stability under pressure, the integration of internal components and the chemical resistance against the fuel. A key question in the tank design is the wall thickness of the tank. It is a result of the initial thickness of the plastic parison and the flow properties of the melted plastic.
Three main types of blow molding are widely used
- Extrusion blow molding
- Injection blow molding and
- Injection stretch blow molding
and in this article we present an extrusion blow molding process in full 3D by which two (initially flat) plastic parts are formed and joined together later. Forming means that the flat parison of variable thickness is blown into a cavity and held there until it is sufficiently cool. NOGRID points can help to understand all phases of the blow molding process, beginning with the clamping (or pressing) of the sheet in the tool, the pressure loading, the first touch of the sheet at the wall and the final stretching to all corners of the tank geometry.
Capabilities of NOGRID points software
NOGRID unites the capabilities to handle free surface flow and moving parts within the domain and allows the simulation of any conceivable mold geometry and operating mode, such as
- blow sheets with individual thickness distribution
- fully 3D computation solving the complete Navier-Stokes equations
- moving of the middle part (for clamping or pressing)
- freely definable material properties by equations or curves
- large tank geometries with small gaps or cutouts and
- open or closed molds, including moving of the middle tool (plunger)
Why choose Nogrid?
NOGRID provides professional CFD software for the simulation of fluid flow, heat and mass transfer, and chemical reactions. Its efficient modelling workflow helps engineers analyse flow behaviour, evaluate designs and make informed decisions without creating a conventional volume mesh.
Faster model preparation
With NOGRID, only the geometry boundary needs to be meshed. The finite points inside the fluid domain are generated automatically according to user-defined settings, both at the start of the simulation and during the calculation.
This approach reduces preprocessing effort and makes it easier to prepare complex geometries and cavities for simulation.
Efficient CFD workflow
The modelling process follows four straightforward steps:
Build the geometry. Mesh the boundary. Define the simulation. Start the calculation.
NOGRID is designed to provide short computation times, including for applications involving complex cavities. Engineers can use the resulting data to examine flow distribution and other relevant flow characteristics.
Better insight into fluid-flow processes
CFD solves the fundamental equations governing fluid flow. NOGRID software enables engineers to predict and analyse the behaviour of fluids and related physical processes before or alongside physical testing.
The simulation results can support:
- evaluation and comparison of design alternatives
- optimisation of construction and operating parameters
- improved planning reliability
- reduction of development time and testing effort
- faster progression from design to market or operation
Steps from geometry generation to simulation results
TRAINING
Our two-day training courses teach participants how to set up, run and evaluate simulations efficiently with NOGRID CFD software. The courses include practical guidance for handling different types of simulation cases.
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Technical Support
Professional support is available from the beginning of your work with NOGRID. Our technical team assists users by telephone and email with software operation, case setup and simulation-related questions.
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Simulation Service
When internal time, expertise or resources are limited, NOGRID can support your project with individual numerical simulation services. Our engineers develop and evaluate CFD models based on the specific requirements of your application.
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