Flow field analysis of cigarette filter through micro-CT-based geometries and CFD simulation

Area of Science:

• * Engineering and Materials Science
• * Fluid Dynamics and Porous Media Research

Background:

• * Cigarette filters are critical for harm reduction and smoking experience.
• * Understanding internal flow distribution is essential for optimizing filter design.

Purpose of the Study:

• * To investigate the influence of wrapped paper and cavities on cigarette filter airflow.
• * To validate a porous media model for predicting pressure drop.
• * To analyze flow field characteristics under varying porosity conditions.

Main Methods:

• * Micro-computed tomography (micro-CT) reverse engineering for 3D model construction (4.05 μm accuracy).
• * Development of an overall porous media model and a local simulation model for cavity-filtered filters.
• * Simulation of flow field dynamics using established boundary conditions.

Main Results:

• * Porous media model accurately predicted pressure drop (less than 3.5% deviation from experimental results).
• * Wrapped paper and cavities significantly increased airflow velocity (141.54% and 130.77% respectively) near acetate fiber interfaces.
• * Increased wrapped paper porosity (0.69 to 0.99) led to higher velocity (+14.46%) and lower pressure (-29.09%).

Conclusions:

• * The porous media model effectively predicts cigarette filter pressure drop.
• * Wrapped paper and cavities are key structural elements influencing internal airflow.
• * Filter design modifications can optimize airflow for reduced harm and enhanced smoking experience.