A microstructural model of Red Blood Cell (RBC) behaviour was proposed. The erythrocyte is treated as a viscoelastic object, which is denoted by a network of virtual particles connected by elastic springs and dampers (Kelvin-Voigt model). The RBC is submerged in plasma modelled by lattice Boltzmann fluid. Fluid – structure interactions are taken into account. The simulations of RBC behaviour during flow in a microchannel and wall impact were performed. The results of RBC deformation during the flow are in good agreement with experimental data. The calculations of erythrocyte disaggregation from the capillary surface show the impact of RBC structure stiffness on the process.
The opportunity to assess haemolysis in a designed artificial heart seems to be one of the most important stages in construction. We propose a new method for assessing haemolysis level in a rotary blood pump. This method is based on CFD calculations using large eddy simulations (LES). This paper presents an approach to haemolysis estimation and shows examples of numerical simulation. Our method does not determine the value of haemolysis but allows for comparison of haemolysis levels between different artificial heart constructions.
The purpose of the studies was to estimate efficiency of delivering nebulised drugs into the lower respiratory tract through endotracheal tubes (ET tubes) which are commonly used in the treatment of uncooperative patients. Water solution of Disodium Cromoglycate (DSCG) was nebulised with a constant air flow (25 l/min). Experimental studies were done for eight ET tubes with varying sizes (internal diameter, length) and made of two different materials. Size distribution of aerosol leaving ET tubes was determined with the use of aerosol spectrometer. Fine Particle Fraction (FPF) and Mass Median Aerodynamic Diameter (MMAD) were calculated for the aerosol leaving each tube. Additionally, mass of the Disodium Cromoglycate deposited into each endotracheal tube was determined. ET tubes can significantly influence the parameters of delivered aerosol depending on their diameter. FPF of aerosol delivered in to the respiratory tract is lower if small endotracheal tubes are used. However, MMAD and FPF for large endotracheal tubes are almost identical with MMAD and FPF from nebuliser. The results indicate that a substantial fraction of large droplets is eliminated from the aerosol stream in long endotracheal tubes (270 mm). In this case the mass of drug delivered through ET tubes is reduced but the content of small droplets increases (high value of FPF).