The effect of the introduction of an exit tube on the separation efficiency in a cyclone

Abstract

-The paper shows the analysis of the effect of introduction of an exit tube into the cylindrical part of a cyclone on the flow velocity, pressure losses and, above all, the separation efficiency. We made measurements and carried out CFD simulations for three levels of the exit tube introduction. The ratios of the depth of the exit tube introduction to the cyclone diameter (Hp/D) were 0.4, 0.475 and 0.89 at three velocity settings of 8 m.s -1 , 13 m.s -1 and 15 m.s -1 . The Reynolds Stress Model (RSM), which was compatible with the experimental results, was used for numerical solutions. The efficiency of cyclone separation was explored on a sample of oak sawdust. The efficiency of cyclone separation increased with the geometric size of the particles, the inlet velocity and a deeper introduction of the exit tube.

The effects of dust extraction on multi-cyclone and non-woven fabric panel filter performance in the air filters used in special vehicles

“…At dust concentration level s = 1 g/m 3 , specific to the vehicles used on testing grounds, the engines of those tanks draw in a stream of dust at 0.94 g/s and 1.67 g/s, respectively. Two-stage air filters in a multi-cyclone -porous panel filter configuration (usually made of paper filter element or non-woven fabric filter element) are used to remove the dust mass, with particle size <100 µm [2,4, 10], from the inlet air stream. The concept of using two-stage filters consists in initial separation of large dust particles in an inertial filter (multi-cyclone) and leaving small dust particles (d z < 15÷30 µm) in the air stream and separating small air particles (above d z = 2÷5 µm) in the panel air filter - Fig.…”

“…Atmospheric air drawn in by the internal combustion engines of motor vehicles contains large quantities of impurities, which can be classified as gaseous impurities (organic and inorganic) and particulate impurities [2,4,5,6]. Dust is a dispersed phase of a two-phase system including particulate matter suspended in a gaseous dispersion phase, i.e.…”

“…15% of both size fractions of the particulate matter [5,27]. The particulate matter from motor transport (road transport) have the following sources [2,5,9]: mineral dust (road dust, with silicon dioxide as a main com-• ponent) lifted from the road surface due to the movement of motor vehicles or wind, exhaust gases from motor vehicle engines (dust, carbon black, • lead compounds, heavy hydrocarbons, particulate matter and gases), particulate matter from sliding pairs of motor vehicles, i.e.…”

“…">ForewordProviding a dust-free inlet air to the internal combustion engines of motor vehicles and machines, and thus reducing wear and improving component life, always was and still is a major operational and design issue, in particular for vehicles operating in heavy-duty terrain and high dust concentration conditions (about 1 g/m 3 ) [2, 10, 12, 18,20, 30]. It generally applies to special vehicles, including military vehicles with high-power diesel engines with a maximum air demand Q Sil over 1 kg/s, e.g.…”

“…The cyclones used in motor vehicles reach up to 96% separation efficiency [2,4,14]. During the 8-hour operation of T-72 tank engine in testing ground conditions, the air filter multi-cyclone may retain over 25 kg of dust.…”