Date of Award

1-2011

Degree Name

Doctor of Philosophy

Department

Mechanical and Aeronautical Engineering

First Advisor

Dr. William W. Liou

Abstract

Vulnerable atherosclerotic plaques have high probability of rupture and are characterized by non-homogenous temperature along the arterial wall. The nonhomogeneous temperature is attributed to the accumulation of heat releasing inflammatory cells in the arterial wall. Rupture of the vulnerable plaque can lead to acute coronary syndrome and sudden cardiac death. Arterial wall thermography (AWT) can be applied to detect the presence of temperature hot spots along the arterial wall by using temperature measurement devices and provide an early detection of a vulnerable atherosclerotic plaque. AWT, however, is invasive in nature.

Computational fluid and heat transport models provide a more efficient and non-intrusive approach to examine the effect of plaque geometry and blood flow parameters on the thermal profile than in-vitro and in-vivo methods. A new thermal immersed boundary method is developed based on the thermal lattice Boltzmann method for the computational simulations of incompressible flows with heat transfer. The new approach is called direct forcing and heating immersed boundary lattice Boltzmann method (IB-LBM). A new and easier method of implementing the Neumann boundary condition and calculation of the local Nusselt number within the immersed boundary method computational framework was proposed and implemented. The new approach was validated with classical benchmark cases for natural convection and forced convection with Dirichlet and Neumann boundary conditions, there was good agreement between the results obtained using the proposed approach and published results in literature.

The proposed direct forcing and heating IB-LBM was then applied to study the effects of blood flow parameters, plaque geometry (macrophage cell density and fibrous cap thickness), macrophage heat generation rate and arterial lumen stenosis on the surface temperature profile of a vulnerable atherosclerotic plaque.

Access Setting

Dissertation-Open Access

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