Embedded CFD Simulation for Blood Flow

The aim of the study is the analysis of strategies and parameters to automate CFD simulations. The idea is to perform an Embedded CFD simulation for product development and verification. This work focuses on biomedical problems, in particular on vessel bifurcations with aneurysm located in the circulatory system. The research is conducted by the analysis of the pre-processing, solving and post-processing steps, in order to find a methodology that involves the reliable calculation of the CFD variables. For the pre-processing step, spatial grids study is conducted to find the element density that allows efficient calculations. The evaluations are done on a blood flow through an ideal artery bifurcation aneurysm. Subsequently the time step entity and the maximum inner iteration number are studied to calculate the independent variables. The time step is evaluated on the ideal bifurcation aneurysm with a constant inlet flow velocity, while the maximum inner iteration value is evaluated on the ideal bifurcation with a time dependent inlet flow velocity. The last study of the preprocessing is conducted on a reconstruction of real artery bifurcation aneurysm, modified with the extrusion of the inlet region, that allow the complete velocity field to develop. For each one, the original and the modified models, it’s generated an unsteady simulation with set up in agreement with previous steps. A correct postprocess management study done through the pulsatile non-stationary simulation. The solution data will be used for the post-processing evaluations. So pressure and velocity evaluation layouts will be identified; Wall Shear Stress (WSS) based indices evaluation layouts will be implemented in order to enable a better evaluation of the case: Time Averaged Wall Shear Stress, Oscillatory Shear Index, Relative Residence Time. Lastly it will be considered a layout about Q-Criterion evaluation. The procedures defined during the study enable a partial automation of the CFD simulations. Acquiring an arterial bifurcation aneurysm model is possible to proceed to the automatic spatial grids generation; the numeric model is used to resolve unsteady flow, set with optimal parameters. Finally it is possible to evaluate the calculated variables by means of appropriate diagrams generation.