Inactivated Parainfluenza Virus Type 3 Stock

Various industrial applications such as medical/pharmaceutical sprays, heating, ventilation and air conditioning systems, and other solid/liquid atomization processes benefit from the characterization of flow and deposition mechanisms of solid/liquid aerosols. This work aimed to experimentally study the transport of solid and liquid aerosol particles which represented aerosolized fission products in a nuclear reactor. We measured the flow field, free-stream concentration, and surface deposition of solid/liquid aerosols flowing in a horizontal square channel with Reynolds number of 750-7, 000. Particle image velocimetry (PIV) was applied to acquire the flow field characteristics such as mean velocity fields and turbulent kinetic energy. The effects of Reynolds number and particle diameter were investigated by studying the particle deposition and penetration of two micron-sized particle types. The experimental results of particle deposition velocity agreed well with the correlations published previously and with the associated numerical results. For the Reynolds numbers tested in this study, solid and liquid particle deposition was found to be governed by gravitational sedimentation. Increasing the Reynolds number for a given particle diameter increased the particle relaxation time and penetration efficiency but decreased the particle deposition velocity. Decreasing the particle diameter for a given Reynolds number increased the effect of gravitation sedimentation. By altering the surface properties with the addition of a carbon nanotube coating, the penetration was shown to decrease for the same flow conditions when compared with a smooth surface. Secondary flow vortices located in the corners, unique to turbulent flow in a square channel, were experimentally shown to increase particle deposition in the corners. Copyright (c) 2020 American Association for Aerosol Research

We examine the behaviour of turbulent boundary layers over surfaces composed of spanwise-alternating smooth and rough strips, where the width of the strips varies such that , where is the boundary-layer thickness averaged over one spanwise wavelength of the heterogeneity. The experiments are configured to examine the influences of spanwise variation in wall shear stress over a large range. Hot-wire anemometry and particle image velocimetry (PIV) reveal that the half-wavelength governs the diameter and strength of the resulting mean secondary flows and hence the observed isovels of the mean streamwise velocity. Three possible cases are observed: limiting cases (either or ), where the secondary flows are confined near the wall or near the roughness change, and intermediate cases (), where the secondary flows are space filling and at their strongest. These secondary flows, however, exhibit a time-dependent behaviour which might be masked by time averaging. Further analysis of the energy spectrogram and fluctuating flow fields obtained from PIV show that the secondary flows meander in a similar manner to that of large-scale structures occurring naturally in turbulence over smooth walls. The meandering of the secondary flows is a function of and is most prominent when .