ABSTRACT
One-dimensional (1D) laminar flow models of Newtonian bile in the biliary tract were built based on clinical observation data. The CD is an idealised rough tube with uniformly staggered baffles along the tube axis, and its wall and baffles can be rigid or compliant with a certain Young’s modulus, but the CHD and CBD are smooth and rigid walls. A flow resistance model for CDs was established and validated with 3D computational fluid dynamic (CFD) simulations based on the equivalent diameter and length proposed. The pressure drop or flow resistance across a biliary tract was predicted in emptying and refilling phases, effects of CD diameter, baffle height, number of baffles and bile viscosity on the pressure drop were clarified by using the models. The pressure drop across the tract in the refilling phase can be ignored compared with the emptying phase. The drop across the CD is so dominant that the drop across the CHD and CBD is negligible. The CD diameter, baffle height and bile viscosity are the most significant factors contributing to the drop and showing an intimate link to the gallstone pathology.
