Development of a Multi-Stage Axial Flow Cyclone

Figures & data

TABLE 1 Dimensions of the impaction inlet and each cyclone stage of the prototype

Stage	Impaction inlet	Stage	#1	#2	#3	#4	#5
Nominal d50	10 μ m	Nominal d50	1 μ m	500 nm	250 nm	100 nm	40 nm
Impacting Length (L)	1.106 cm	Pitch (P)	0.675 cm	0.437	0.357	0.278	0.278
Dust Bin Hole (d)	1.106 cm	Channel Depth (T)	0.814 cm	0.457	0.378	0.378	0.378
		BodyDia.(D)*	4.169 cm	4.169	2.899	2.899	2.899
		Body Length (H)	7.620 cm	7.620	5.842	5.842	5.842
		Outlet Length (OL)	4.970 cm	4.970	3.810	3.810	3.810
		Outlet Dia.(De)	0.953 cm	0.953	0.635	0.635	0.635

FIG. 1 (a) Schematic diagram of the overall system of the prototype. (b) Schematic diagram of an axial flow cyclone stage (Stages #1–5). (c) Schematic diagram of the impaction inlet.

FIG. 2 Schematic diagram of experimental setup for the calibration of the impaction inlet and individual cyclone stages.

TABLE 2 Experimental setups for the individual calibration of the impaction inlet and cyclone stages

Stage	Impaction inlet	#1	#2	#3	#4	#5
Aerosol Generator	PGS1	PGS2		PGS3		PGS4
Sizing or Counting Apparatus	Aerodynamic Particle Sizer		SMPS	Faraday Cage with Electrometer

FIG. 3 Particle collection efficiency curves for the 4th cyclone stage under two different pressure conditions (i.e., 319 torr and 274 torr) at 20 lpm. (a) aerodynamic size as the abscissa; (b) square root of StK number as the abscissa.

TABLE 3 Experimental cutoff particle sizes of the impaction inlet and cyclone stages (Note that two orifice plates were installed in the assembled cyclone prototype to regulate the upstream pressures of Stages 4 and 5: one is between Stages 3 and 4 and the other between Stages 4 and 5)

Stage	Nominal d50	Test flowrate*	Upstream pressure	Downstream pressure	Re#	Experimental d50
Impaction Inlet	10 μ rn	50 lpm	760 torr	760 torr	3046	11.3 μ rn
#1-1	1 μ m	50 lpm	760 torr	760 torr	41499	1 μ m
#1-2	1 μ m	20 lpm	760 torr	760 torr	16600	1.87 μ m
#2	500 nm	50 lpm	760 torr	760 torr	114241	550 nm
#3	250 nm	50 lpm	760 torr	578 torr	117488	290 nm
#4-1	100 nm	20 lpm	319 torr	228 torr	60423	229 nm
#4-2	100 nm	20 lpm	274 torr	175 torr	60423	161 nm
#5	40 nm	1 lpm	21.8 torr	6.7 torr	3021	40.9 nm

FIG. 4 Measured collection efficiency curves of the impaction inlet and individual cyclone stages of the prototype.

FIG. 5 Collection efficiency curves as a function of the particle Stokes number for all the axial flow cyclone stages of the prototype.

FIG. 6 Dimensionless cutoff size (StK ₅₀ ^0.5) vs. flow Reynolds number for all axial flow cyclone stages.

FIG. 7 Overall flow operation scheme of the prototype and the corresponding cutoff sizes for the impaction inlet and cyclone stages.