Multiphase Code Repository by HZDR

The majority of the developments for numerical simulation of multiphase flows at HZDR are implemented in the open source software released by the OpenFOAM Foundation, which is the leading open source software package for numerical simulations of fluid flows (Computational Fluid Dynamics, CFD) in engineering applications. By signing the Contributors Agreement with the OpenFOAM Foundation in 2017, HZDR has the unique opportunity to actively participate in the development of this software. An example is the contribution of the population balance modelling framework in 2017 together with VTT Technical Research Centre of Finland Ltd, which is continuously developed and improved since.

Besides, HZDR develops an extension for multiphase flows, the Multiphase Code Repository, and a validation database, the Multiphase Cases Repository, both published via Rossendorfer Data Repository. Since 2019, HZDR coordinates the development work for Nuclear Safety Repository for OpenFOAM Foundation Software for Reactor Cooling System (NUSAR-RCS), which is an extension for the software released by the OpenFOAM Foundation to simulate the primary cooling circuit in a nuclear power plant. As a member of the OpenFOAM Process Engineering Consortium, HZDR has established a strong cooperation with the chemical and process engineering industry to ensure that the research done on multiphase flows fits industrial needs.

Highlights

• MultiMorph Model: A morphology-adaptive multifield two-fluid model
• Baseline Model by HZDR for polydisperse bubbly flows
• A GPU-accelerated class method to solve the population balance equation
• Scientific workflow based on Snakemake workflow management
• more

Example of a numerical simulation of a plunging jet with the multi morph model showing a resolved water surface, resolved large gas bubbles and the probability of small gas bubbles. See here for a demonstration video of the morphology-adaptive multifield two-fluid for a plunging jet into a water basin.

Contributor with an Addon

The open source software released by the OpenFOAM Foundation is written in state-of-the-art, object-oriented C++ and licensed under GNU GPL v3 license. Excellent code quality and robustness of the code base is ensured by the maintenance work of the OpenFOAM Foundation, which is a major requirement for CFD software in industrial design processes. The OpenFOAM Foundation follows a continuous integration strategy to reduce the amount of bugs in the source code. This development strategy has higher demands on downstream developers, like HZDR. Contributions to the release are a key prerequisite for industrial application of our developments. However, the demands on software quality are high and cannot always be ensured in research.

Hence, HZDR develops the Multiphase Code Repository, which primarily includes prototype functionality. The flexible interfaces of the software released by the OpenFOAM Foundation and a early communication with the core developers makes sure the maintenance generated by the add-on is minimised. A support contract with CFD Direct ensures that the long-term maintenance and the integration costs of HZDR's release contributions are covered.

Illustration of the linkage between software released by the OpenFOAM Foundation and Multiphase Code Repository by HZDR.