This paper discusses PM₁₀ (particle matter with a diameter less than 10 μm) grade collection efficiencies of a laboratory electrostatic precipitator (ESP) in terms of the electric field, corona discharge power, and gas flow patterns by means of the particle image velocimetry(PIV)and the electrical low pressure impactor (ELPI) technique. The wire-plate ESP has a plate-plate distance of 200 mm, together with a single or two high-voltage electrodes. Moxa-moxibustion smoke is used as the tracer for evaluation of the gas flow and particle grade collection efficiency. Experiments, performed in air with a total gas flow rate of 85 m³/h and initial particle mass concentration of around 33 mg/m³, show that with increasing the field strength or corona discharge power, the flow changes from regular vortexes around the corona wire to multi-vortexes inter-reacting each other. As a result, optimizing the distribution of corona discharge ion wind is the key to increase PM₁₀ collection efficiencies and reduce the power consumption. In terms of the particle number concentration and the applied electric field or corona discharge power, two ESP performance regions can be distinguished: Below 3 kV/cm, the grade collection efficiency increases with the rise of field strength or ESP index; it tends to saturate or drop when the field becomes higher than 3 kV/cm.

electrostatic precipitation  /  particle image velocimetry  /  PM_2.5  /  PM₁₀