E. Nino, R. Fasanella, R.M. Di Tommaso
Building and Environment,Volume 46, Issue 11, November 2011
In several technical applications, it is convenient to carry out physical separation between two neighboring zones with different physical characteristics (such as temperature or contaminant concentration), using a two dimensional gaseous jet, often called air curtain. In this paper, a submerged rectangular air jet, simulating an air curtain, has been investigated in order to infer the capability to reduce the transfer of dusty air between a “clean” zone and a contaminated environment (dusty zone). The investigated jet was generated by means of a rectangular nozzle with a discharge area of 0.02 square meters, while the dust has been simulated using atomized distilled water in a cloud of small droplets, sprayed transversally against the air curtain. Experiments have been performed running the air curtain at Reynolds Number(Re) ranging from 4500 to 25,500 while the Sauter Mean Diameter (SMD) of atomized water was equal to 6 microns. The water spray has been characterized using a TSI single component fiber optics Phase Döppler Particle Analyzer (PDPA), and the air curtain has been investigated by means of a Particle Image Velocimetry (PIV) technique. The amount, size distribution and velocity of the droplet cloud able to cross the air curtain was measured, obtaining as the main result, the dependence of the amount of droplets passing the barrier as a function of the Re of the air curtain. For a Re as high as 25,500, the curtain is able to interrupt the amount of surviving droplets, i.e. all the dust is rejected.
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