报告内容摘要

A 1D simulation of the complete vessel network, THINkS (Total Human Intravascular Network Simulation), is introduced to improve the accuracy of computational fluid dynamic (CFD) calculations and better define boundary conditions of the complex human vessel network. THINkS is a 1D network simulation of the complete human circulatory system. It consists of a simulation of 85 major arteries, 158 major veins, 43 arterial and 77 venous junctions. Blood flow in arterioles, capillaries and venules is modeled using lumped parameter models, or the 0D models, which are modeled using the connection of a number of capacitors, resistors and inductors to represent the real physics. The model used a simple 0D model for 20 one-artery-to-one-vein micro circulations and 4 other 0D models for 7 complex arteries-to-veins micro circulations. Moreover, a 4-chamber 0D model for the heart is used to allow blood to pump from superior vena cava I and inferior vena cava I veins, through the pulmonary system, and discharge back to the ascending aorta artery. In addition to the 4 valves inside the heart, there are also 15 venous valves used in the venous system. THINkS calculates the complete human

THINkS has been validated against experimental data and shown to respond correctly to the flow pattern changes caused by variations in the Circle of Willis (CoW).   The overall trends of the simulation results for estimating flow rates in the missing A1 and the missing P1 CoW variations are confirmed by the in vivo experimental data.A test of a wide range of CoW variations has suggested that the ring-like vessel connection can regulate the blood flow to enable different parts of brain to receive the same blood flow rates.  The mechanics are built into the ring-like structure (passive regulation) and require no external stimulus (active regulation)?. Although the flow rates in efferent arteries remain unaffected by the variation of CoW, the flow rates in afferent vessels can subject to substantial changes. The redistribution of flow due to CoW variation may cause some vessels to carry excessive load, leading to high wall shear stress in certain flow regions.  This provides an explanation why the CoW variation (missing A1) is correlated with a higher prevalence of anterior communicating artery aneurysms.  A new direction of research to correlate CoW variations to different vascular diseases by taking into consideration the redistribution of the flow is therefore suggested.

报告人简介

Dr. George Huang is the Professor and Chair in the Department of Mechanical and Materials Engineering at Wright State University (WSU).  Dr. Huang completed his undergraduate degree in Taiwan (CYCU), MS in Canada (McGill University) and PhD from Manchester, England (UMIST). Dr. Huang began his career at Michigan Technology University as an Assistant Professor in the Department of Mechanical Engineering.  After 3 years, he moved to Stanford University and NASA-Ames to pursue his interests in high-speed flow research related to the National Aero Space Plane (NASP).  Having enjoyed the good weather in northern California for 7 years, Dr. Huang joined the Department of Mechanical Engineering at the University of Kentucky as an Associate Professor and was subsequently promoted to the full Professor. During this period of time, he was supported by NASA to pursue his research in modeling of low pressure turbine flows.  He also undertook the administrative duty as the Director of Graduate Studies of the Department of Mechanical Engineering at the University of Kentucky for four years. In 2006, Dr. Huang joined Wright State University (WSU) as the Chair of the Mechanical and Materials Engineering Department. At WSU, he initiated a very successful project-based learning (PBL) program for students and funded a number of research centers to support his PBL activities. Among them, the Ohio Center of Excellence for Micro Air Vehicle Studies (CMAVS) becomes a world renowned center for UAV research and the vehicle designed by his students was cited as the drone of the future by the WIRED magazine.  Recently, he has developed a new research program in using CFD  to study human blood circulation. Dr. Huang received a number of awards,  including NASA software of the year honorable mention award, Ackroyd Stuart prize and Silver Award of British Royal Aeronautical Society.  He is also a fellow of ASME, an associate Fellow of AIAA and a Professional Engineer in Mechanical Engineering.