Precise Bubble Point determination through simulation and analysis with GeoDict
Assess the minimum passable pore size to improve filter and membrane processes through physics-based simulations
The bubble point is a key parameter in the characterization of porous materials such as filter media, membranes, textiles, and paper structures. It refers to the pressure at which the first gas bubble pushes through the largest liquid-filled pore of a material. This point marks the transition from a fully liquid-saturated state to one that is permeable to gas, providing direct insight into the material's largest effective pore size.
In practice, the bubble point is an important quality indicator:
- In filtration technology, it is used to evaluate filter retention performance and operational safety.
- In material development, it offers insights into pore structure and the consistency of the manufacturing process.
- In the pharmaceutical and food industries, it serves as evidence of membrane integrity and homogeneity.
Traditionally, the bubble point is determined using pressure-controlled gas-liquid flow experiments. While well established, these tests are often time-consuming and costly, and they can be affected by measurement uncertainties. For example, due to wetting errors, temperature and surface effects, or incomplete knowledge of the material's internal structure.
In addition, experimental methods offer little insight into the local pore-scale mechanisms that trigger the initial gas breakthrough. This is where bubble point simulation comes into play. With GeoDict, the bubble point is simulated accurately and reproducibly, based directly on real 3D microstructural data obtained from µCT images.
GeoDict's simulation approach relies on direct numerical simulation of two-phase flow in realistic microstructures, offering several key advantages:
- Image-based analysis using real µCT data
- Physically accurate modeling of interfacial dynamics
- Integration with pore network models for fast evaluations
- Automated identification of the largest continuous pore
The result is an objective, reproducible, and in-depth bubble point analysis that goes beyond individual measurements to deliver a comprehensive understanding of the underlying physical processes.
- Time savings: Results are available in hours rather than days
- High accuracy: Full control over boundary conditions and simulation parameters
- Cost efficiency: Reduced need for extensive laboratory testing
- High efficiency: Complex physical experiments are eliminated, allowing rapid virtual testing of multiple material variants
- Reproducibility: No laboratory errors or environmental influences. The entire process runs virtually under well-defined, ideal conditions
- High precision: Key physical parameters such as surface tension, contact angle, and pressure are precisely defined and controlled
- In-depth insights: Detailed understanding of local gas breakthrough mechanisms and the specific pores involved
- Scalability: Applicable to a wide range of materials, including filter media, textiles, paper, and more
Wire mesh structures are generated using WeaveGeo or imported directly into GeoDict from µCT scans via the ImportGeo-Vol module. In the next step, the structure is analyzed using a bubble pressure test in accordance with ASTM standard E3278-21. This standard defines software-based pore size calculations derived from bubble point simulations performed with the PoroDict module.
The percolation path-based adjustment of the particle diameter calculated by PoroDict was previously defined in ASTM standard 2814-18 (Table 1) to match the results of glass bead tests. In ASTM standard E3278-21, this approach is extended through the use of a pore size calculation factor (CF), which is applied to determine the pore size of the filter cloth from the simulated bubble point pressure.
GeoDict digital solution for meshes
The GeoDict package comprises GeoDict Base along with all modules necessary for advanced research and development of mesh structures.
Module recommendations
| Image processing and analysis | ImportGeo-Vol | |
| Characterization and analysis | PoroDict + MatDict | |
| Modeling & Design | WeaveGeo | FiberGeo |
Which modules suit you best depends on the nature of your application.
