Fluid mechanical evaluation of in-line filter for fluid-handling systems by means of computational fluid dynamics (CFD)

Abstract Administering fluids and drugs intravenously is crucial in caring for vulnerable patient cohorts such as critically ill patients as well as neonatal and paediatrics patient populations. Studies have revealed severe contamination of infusion solution that could be avoided by utilizing in-line filters. The filtration performance consequently depends on the geometry of the filter housing. The purpose of our numerical study was to analyse the flow situation in filter housings depending on the geometry (diameter of the filter housing and distance between entrance and membrane). We compared the flow of two circular filter system with different housing width (D = 25 mm; L = 1.5 mm/3.0 mm) by means of computational fluid dynamics (CFD). The filter membrane was modelled by a porous jump condition. Both filter systems showed a highly reduced inflow on the membrane compared to the velocity in the Luer Lock ports. The wide filter housing facilitates a more homogenous inflow on the membrane (>92% of the membrane area is applied within a range of 5% of the mean velocity) compared to the narrow filter housing. Despite that difference both filter housings induced a well distributed flow through the filter membrane. However, for large filter systems (>50 mm diameter) the design of the filter housing could play a crucial role in optimising filter performance and therefore CFD should be considered.