Parainfluenza 1 (strain sendai)

This work investigates experimentally the effects of grid-generated turbulence on the evaporation of thin oil films subjected to laminar, transitional, and turbulent boundary layers. Particle image velocimetry (PIV) is used to characterize flow development within a rectangular duct (20 mm x 40 mm) with a length of 1 m (similar to 40D(h)). The inlet turbulence intensity is manipulated using wire meshes, and experiments are performed for Reynolds numbers based on the duct hydraulic diameter of 10,650, 17,750, and 35,500. Mass transfer measurements are conducted under the characterized boundary layers for oil films with initial thicknesses of 50 mu m at a constant substrate temperature of 150 degrees C. The Reynolds number is shown to have a significant impact on the evaporation rate, whereas varying near-wall turbulence intensity is shown to have little effect for the parameters investigated in this study. This implies that mean wall shear and transport within the viscous sublayer are the predominant parameters governing the convection-limited mass transfer considered in this investigation.

Droplet heat transfer in between parallelly located superhydrophobic plates is examined. The thermal field inside the droplet is predicted by adopting the experimental conditions. The influence of plates spacing (heights) on the thermal response of the droplet fluid is investigated. Particle injection velocimetry (PIV) is used to validate the velocity predictions. We demonstrated that predictions of flow velocity are in agreement with those of the PIV results. The heating of the droplet in the absence of the top plate gives four circulation cells in the droplet. Once the top superhydrophobic plate is introduced, the flow structure alters, and the number of the circulating structures reduces to two. Lowering the height of the plates increases the droplet Laplace pressure while modifying the fluid flow and thermal behavior. The Bond number is lower than one for all the cases considered; hence, demonstrating that the Marangoni force affects the formation of the circulation cells. The cells redistribute the heated fluid in the droplet interior, which is clearly apparent for the plates with small heights. Temperature enhancement in the droplet bottom section is attributed to the flow current formed due to heat diffusion. The Nusselt number corresponding to the bottom plate increases as the plate heights reduces; however, the opposite is true for that corresponding to the top plate.