A sensitivity analysis of CFD simulations of aerosols produced by metered dose inhalers in valved holding chambers

DE CHARRAS, YAMILA; RAMÍREZ RIGO, M. VERÓNICA; BERTIN, DIEGO E.

Buenos Aires

Congreso; WCCE11 - 11th Congress Of Chemical Engineering; 2023

AAIQ Asociación Argentina de Ingenieros Químicos

Valved Holding Chambers (VHCs) are medical devices that improve the efficiency of inhalation therapy when using pressurized metered-dose inhalers (pMDIs) by modifying the aerodynamic particle size distribution of the aerosol inhaled by the patient. The flow of the emitted aerosol is multiphase and is influenced by many factors. In this context, computational fluid dynamics is a valuable tool to assess, understand and evaluate the potential and performance of VHCs. The objective of this work was to perform a sensitivity analysis to determine how various submodels or parameters (relevant in the MDI-VHCs system) impact the simulation outcome. The results showed that typical aerosol parameters, such as spray angle and spray velocity, do not affect the air phase and particle retention results. On the other hand, a change in the air flowrate, associated with inspiratory flow, generates only significant changes in the air results. The simulation results obtained were found independent of the turbulent models used. On the other hand, an increase in the time scale constant 𝐶𝐿 generates a linear increase in the percentage of retained particles, so it is suggested to modify this parameter for a better agreement with experimental results.