Particulate Matter Detachment from a Magnetizable Single Fiber Applying Magnetic Forces in Ambient Air

Abstract

The potential utilization of magnetic effects in gas particle separation is a current subject of research. This paper demonstrates for the first time that a single magnetizable filter fiber can be deflected by a magnetically induced excitation for a selected combination of parameters, resulting in the removal of deposited particle structures with high detachment levels. A correlation between the magnetic flux density and achieved acceleration to overcome the adhesive forces/strength of the particle structure was determined. The degree of detachment after each regeneration was calculated by comparing the projection area before and after detachment using high-speed images. At a magnetic flux density of B = 38.5 mT, accelerations of maximum a = 105 m·s−2 are achieved, depending on the axial position along the single fiber. The degrees of regeneration achieved at these parameters depend on the amount of fiber loading and on the fiber orientation in the gravitational field. The horizontal orientation of the fiber leads to an increased reattachment of precedingly detached particle structures after deflection compared to a vertical orientation. High particle loading on the fiber results in enhanced detachment by inertia. Under the most favorable process conditions investigated, detachment levels of > 90% are achieved.

Experimental Investigations of the Detachment of Different Particle Structures from a Magnetizable Fiber in the Gas Phase

“…As shown in a previous study [26], the particle morphology (structure) and the particle loading stage (height of the structure) are crucial for the efficiency of particle detachment. The resulting morphology depends on the prevailing transport mechanism (diffusion, interception, inertia) of the particles to the fiber during deposition [27,28].…”

“…In this experiment, the guide width was always w = 0.5 mm. The impact of the guidance on the fiber movement is negligible, which was investigated in a previous study [26].…”

“…The steel has a density of ρ = 7700 kg•m −3 and Young's modulus of E = 2.2 × 10 11 Pa. When the axis of the fiber is oriented perpendicular to the external field, the magnetization of the fiber increases linearly in the range of the field strengths used (H = 0-30,000 A•m −1 ) [26,29]. The same fiber material was already applied in previous studies [26,27].…”

“…Figure 1 presents the same setup applied in a previous study [26] for the particle deposition and detachment.…”

“…Since the fiber is only fixed on one side and has a loose end, it is not possible to position it exactly perpendicular to the magnetic field. The initial angle of the fiber to the field lines varies in the range of α = 87.4-89.5 • , which was determined in [26].…”