Computational fluid dynamic modeling of the airflow perturbation device

Abstract

Computational Fluid Dynamics (CFD) of Airflow through the airflow perturbation device during normal exhalation was performed to assess the effect of outlet blockage, temperature and turbulence on air flow and pressure patterns. Five models were analyzed with 0%, 30%, 50%, 70% and 90% outlet blockage. Maximum velocity increased with increasing outlet blockage percentage (from 0 to 90%) from 2.36 (m/s) to 16.31 (m/s) and maximum static pressure increased from 3.25 (Pa) to 200 (Pa). Turbulence did not show a significant effect. Density changed less than 1% when blockage percentage is more than 70%. Density ranged from 1.139 to 1.141 (kg.m-3) in the model with 90% outlet blockage. Increasing the temperature from 25 to 37 °C did not affect the static pressure and velocity significantly. © 2010 Springer-Verlag.