Reconstruction of Central Airways from CT Scans and Computational Analysis of Flow and Structural Defor-mation in Fibrosis-Inspired Mechanical Model

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease character-ized by parenchymal scarring, increased tissue stiffness, and impaired gas exchange. This study investigates the fluid dynamics and structural response of central airways in both healthy and fibrosis-inspired lungs under a 50% increased flow demand. A three-dimensional airway geometry was reconstructed from computed tomography (CT) scans up to the fifth bronchial generation using a hybrid modeling approach. Transient computational fluid dynamics (CFD) simulations of inhalation and exhalation were performed using ANSYS Fluent with the SST k-ω turbulence model. A complementary static structural analysis was conducted to assess deformation and stress under pleural pressure loading. Results indicate that fibrosis-inspired lungs required 92% higher inlet pressure losses compared to healthy lungs, highlighting the increased energetic cost of breathing. Flow patterns remained qualitatively similar. Structurally, fibrosis-inspired tissue exhibited 17% lower equivalent elastic strain under the same pressure load, confirming the impact of increased stiffness on bronchial dis-tensibility. Maximum principal stress concentrations of 22.1 kPa were identified at the left main bronchus bifurcation, indicating potential mechanical stress hotspots.