Numerical And Experimental Investigation Of Pulsating Flow In 3D Bifurcation Pipe

The thesis used engineering methods to solve medical problems. It applied the hydrodynamics principles and techniques to analyze the characteristics of the pulsatile blood flow, such as unsteady flow and fluid-structure interaction. The means of numerical simulation of unsteady flow and flow visualization of PIV and fluorescence were also employed in the investigation of local characteristics of hemodynamics at carotid bifurcation.In the first part of this thesis, considerable numerical efforts have been made to gain a detailed view of hemodynamic characteristics of carotid bifurcation. Three-dimensional tuning-fork-shaped models based on the statistical anatomical data of human carotid bifurcation were generated with 0, 20% and 40% stenosis by Unigraphics CAD. Computational fluid dynamics (CFD) was used to simulate the three-dimensional pulsating blood flow in the models. Clinical data of pulsatile flow rate were imposed on the CFD models as boundary conditions. Two types of liquid (non-Newtonian fluid and Newtonian fluid) were discussed in terms of velocity field, particle residence, wall shear stress (WSS), etc.In the second part, the flow visualization methods of PIV and fluorescence were applied in the experimental study. Under the pulsatile flow generated by advanced equipment, a series of well-connected experiments were carried on with two models made by plexiglass and silicon. The effects of wall elasticity on the local characteristics of flow were also investigated by the numerical simulation in the first part and fluorescence experiments.In the last part, all the findings in the former study were checked with a real geometry, which was reconstructed on the basis of the Magnetic Resonance Images (MRIs) of a patient. With CFD simulation, the local characteristics of hemodynamics at patient's carotid bifurcation were studied. This may provide a new method and some essential information for surgical diagnosis, and eventually lead to the improvement in the treatment of arteriosclerosis.In this thesis, the knowledge, techniques and methods of engineering science were used to investigate the hemodynamics of carotid bifurcation. The author hopes the explored study may make positive effects on the future investigation of medical engineering.