Multiscale Computational Methods for Heat Transfer Simulation between Body Tissue and Blood Flow

Estimating heat transfer in the human body is challenging due to the complexity of its heterogeneous tissues and blood vessels at different scales. To address this challenge, many bioheat models have been developed but they often rely on simplistic approaches when modeling heat transfer between blood and tissues, limiting the realistic evaluation of heat flux between two and the interactions with blood flow. To overcome these limitations, we developed multiscale computational methods by considering the interactions between blood flow and nearby tissues. Blood flow and heat transfer are solved using one-dimensional (1D) flow and advection-diffusion equations. The advection-diffusion equation is modeled to have radial variations to estimate the heat flux occurring at the boundary between blood and nearby tissues. The computed temperature distribution is utilized as boundary conditions to a three-dimensional heat equation which is solved for the tissue. Heat flux at the boundary between blood and nearby tissues is updated and explicitly fed back to the 1D advection-diffusion equation. The interactions between blood and tissues with an explicit coupling will be demonstrated for idealized geometries and complex geometries with varying scales of blood vessels. The developed methods will be utilized to estimate the effects of thermal therapy on blood flow within body tissues using a commercial thermo-mechanical massage bed.