Increasing the Rate of Pollutants Capture by Local Exhaust Due to the Use of External Swirling Jet. Part 2. Results of Numerical and Experimental Studies.

To capture pollutants in various buildings and structures, it is necessary to use local exhaust systems. It is proposed to increase one of the criteria for the local exhaust efficiency, i.e. the rate of pollutants capture, due to the impact of a swirling annular jet and the occurrence of a reverse air flow. In order to do that, a circular exhaust was placed coaxially in an outer cylindrical casing, in which the air flow was swirled due to the tangential supply of two supply jets into the casing, resulting in a vortex dome, which contributed to an increase in the efficiency of such a vortex exhaust. The change in the axial air velocity at a distance from the vortex exhaust was experimentally and numerically studied for 11 structures, in each of which 4 different ratios of exhaust and supply air flow rates were set. In the studied applications of the proposed exhaust systems, the velocity increases significantly at a certain range of distances from them. A combination of design and mode parameters that contribute to the highest capture rate by vortex exhaust has been determined. The results obtained can be used to design efficient exhaust systems to capture pollutants. [ABSTRACT FROM AUTHOR]