This work investigates the turbulent ow and particles deposition in wavy duct ows. The v2f turbulence model was used for simulating the turbulent ow through the wavy channel. The instantaneous turbulence uctuating velocities were simulated using the Kraichnan Gaussian random eld model. For tracking particles in the uid ow, the particle equation of motion was solved numerically. The drag, Sa man lift, Brownian, and gravity forces acting on a suspended particle were included in the particle equation of motion. The e ects of duct wave amplitude and wavelength on deposition of particles of di erent sizes were studied. A range of waves with di erent amplitudes and wavelengths was simulated. The particle tracking approach was validated for turbulent ow in a at horizontal channel, where good agreement with previous studies was found. The presented results showed that the duct wavy walls signi cantly increased the particle deposition rate.
As surrogates to human beings, rats are used occasionally to study the therapeutic impact of inhaled pulmonary drug particles in microscale. To speculate human responses from rat studies, scale-up factors are widely used to extrapolate particle lung deposition from rat to human. However, available scale-up methods are highly simplified and not accurate, because they directly use the human-to-rat ratios of body weights (RBW) or lung surface areas (RSA) as the scale-up factor. To find a precise scale-up strategy, an experimentally validated Computational Fluid-Particle Dynamics (CFPD) was employed to simulate the transport and deposition of microparticles in both human and rate respiratory systems, which encompasses the pulmonary routes from mouth/nose to airways up to Generation 17 (G17) for human and G23 for the rat. Microparticles with the same range of Stk/Fr were injected into both models with the airflow at resting conditions. Numerical results indicate that particles (with the size ranging from 1 to 13 μm for humans and 0.6 to 6 μm for rat) have similar deposition pattern (DP) and deposition fraction (DF) in both models, which are resulted from both inertial impaction and gravitational sedimentation effects. A novel correlation is proposed to predict DFs in both human and rat respiratory systems as a function of the ratio of Stokes number to Froude number (Stk/Fr). Using the correlation as the novel scale-up tool, inter-species extrapolations can be precisely done on predicting particle depositions in human respiratory systems based on the deposition data in rats obtained from animal studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.