Push-pull ventilation system: a CFD approach for the performance analysis

In this paper the results of a CFD investigation for a push-pull local ventilation system are presented. The velocity field and the capture efficiency prediction are investigated for different system arrangements. The analysis is carried out for systems respectively with and without fluiddynamic obstacle in the working plane and for dust pollutants with particle diameters ranging from 1.0 to 100 pm and emission velocities between 1.0 and 7.0 m/s. The analysis, carried out using the commercial code FLUENT, shows that the system performances are dependent on operating conditions and are influenced by the presence of the above-mentioned obstacle on the working plane. In the case of working plane emission without obstacle the system capture efficiency is in general very low never exceeding 25%. Higher efficiencies are instead achieved for particle emission from a vessel placed in the system's working plane centre. In this case even unitary peak efficiencies are reached for particular operating conditions.