In many areas of filtration application, woven filters are the preferred media type due to defined filtration properties, durability and mechanical strength. The latter feature is particularly important to counter the deformation caused by the fluid flow through the porous medium during operation.

When searching for the optimal combination of yarn material(s) and weave design (yarn strength, weave pattern) for a given application, an experimental approach using prototypes can become time-consuming and costly. In addition, empirical knowledge is of limited use when new yarn materials or material combinations are to be considered. Suitable simulation techniques can help to significantly accelerate this stage of product development and optimization.

To this end, a specialized software tool is used for both the design of the woven filter fabric and the prediction of its mechanical strength. Known quantities such as the weaving pattern, yarn diameter(s) and the yarn materials – especially their mechanical properties – serve as input data for the computation. Instead of performing 3D simulations for finding properties like tensile strength and flexural rigidity of the fabric, the simulation is sped up tremendously by using highly efficient beam models.

The simulation results are validated by comparing them to experimental data obtained by mechanical testing.

The results are applied to the coupled simulation of the deformation of the filter fabric under stationary flow on the macroscopic scale. On this length scale, a direct numerical simulation that resolves the open areas and the yarn in the grid and uses a fluid-structure interaction applied to the solid yarn would require a lot of computational resources and time. Instead, a multiscale approach as in [1] is taken: By performing CFD simulations on the microscopic length scale (i.e. the scale of the mesh holes and yarns), the flow resistance of the fabric is obtained for different strain rates. This is used for the simulation on the macroscopic scale, where the filter fabric is modelled as a (poro-)elastic shell with the effective flow resistance and mechanical properties obtained from the mesh-scale simulations. Based on the operating conditions (volumetric flow rate) a CFD simulation computes an initial pressure distribution, which represents the mechanical load on the filter fabric. This data is used for simulation of the deformation of the fabric. For the new state, another CFD simulation updates the pressure distribution. This cycle is repeated until a steady state in terms of deformation is reached.

The present paper presents the approach and the results in detail, particularly the improvements compared to previous methods...