engleski

Human Heart Blood Flow Numerical Modelling and Simulations

In order to make a correct choice of the artificial heart valve for curing patients with cardio vascular disorder it is very important to know in detail the blood flow in the heart of the specific patient. In this book chapter, two separate approaches are presented on how to model the blood flow within the real human heart. The first approach is based on Magnetic Resonance Imaging/Tomography to get shape (“geometry”) of internal heart volumes in time (tens or hundreds of frames for one heartbeat), and applies a Computational Fluid Dynamics (CFD) tool for simulating and visualizing a blood flow. The second approach is based on the SIMULIA Abaqus LHHM model, combining the structural heart Finite Element Model (FEM) with the CFD simulation to solve the fluid structure interaction problem. The blood flow circulation through the heart is numerically simulated with a modern FlowVision code that has a fully automatic mesh generation using arbitrary cell shapes for dynamic mesh refinement and taking into account the motion of the heart surface, applying the Euler coordinates. The second approach solves the bidirectional fluid- structure interaction problem applying the general purpose CFD code FlowVision and the SIMULIA Living Heart Human Model (LHHM), a dynamic, anatomically realistic, 4-chamber heart model with mechanical valves that considers the interplay and coupling of electrical and mechanical fields, which are acting simultaneously to regulate the heart filling, ejection, and overall like pump functions. LHHM natively includes a 1D fluid network model capable of representing dynamic pressure/volume changes in the intra- and extra-cardiac circulation. In the current work, this network model is first replaced with a full 3D blood model (solved in FlowVision) that provides detailed spatial and temporal resolution of cardiac hemodynamic driven by motions of the beating heart and constrained with appropriate time-varying boundary conditions derived from the literature. After validating this approach, the bidirectional coupling between the blood flow CFD model and the LHHM electromechanical model is activated by using the SIMULIA co- simulation engine and in conclusion the modelling details and results of interest are discussed. Using the real heart MRI/MRT has tested the described approaches of simulating the blood flow and SIMULIA Abaqus LHHM and the simulation results are presented.

CFD simulation ; Human heart ; Internal flow ; Time-variant shape

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