Fluid-structure interaction analysis of air flow in pulmonary alveoli during normal breathing in healthy humans

Abstract

Abstract. In this work, the human lung alveoli are idealized by a three dimensional honeycomb like geometry and a uid-structure analysis is performed to study the normal breathing mechanics. In contrast to previous works in which the inlet ow rate is prede ned, in this model, we have applied a negative pressure on the outside surface of the alveolus which causes air to ow in and out of the alveolus. The integration of the experimental curve of breathing ow rate was used to approximate the shape of the external applied pressure. Our Fluid-Structure Interaction (FSI) model has an advantage over other literature since it addresses both the uid dynamics and solid mechanics, simultaneously. The ow patterns con rmed that there is no circulation in the terminal alveolus. We have applied three distinct material models { linear isotropic elastic, hyperelastic, and viscoelastic { in order to simulate the mechanical behavior of alveolar wall tissue using ADINA software. The hysteresis behavior of the alveolar tissue was well predicted by a compliance diagram of the viscoelastic model while this behavior is not observed in the linear elastic and hyperelastic model. The stress and strain distribution is also obtained and is found to be non-uniform.

Submicron particle deposition in pulmonary alveoli during cyclic breathing

“…The maximum value for local stretch is about 1.2 occurring at t = 1:4, which is in agreement with the X-ray microscopy performed by Raush et al [22]. We have presented more results about alveolus mechanics elsewhere [23].…”

Surface tension effects on flow dynamics and alveolar mechanics in the acinar region of human lung

“…Results revealed that high surface tension values contributed to hysteresis of lung tissue with minor changes in airflow rate, volume-pressure relationship, and alveolar resistance. Monjezi and Saidi (2016) incorporated surface tension into a honeycomb-like alveolar geometry to assess its ramifications on alveolar deformations (stretches) and stresses. They adjusted the Mooney Rivlin model's parameter constants to capture the surface tension effect.…”