Effect of particle size distribution on the performance of electrodynamic screens C. E. Johnson, P. K. Srirama, R. Sharma, K. Pruessner, J. Zhang, and M. K. Mazumder Applied Science Department University of Arkansas at Little Rock Little Rock, Arkansas; USA Email: mkmazumder@ualr.edu Abstract— Electrodynamic screens (EDS) consist of rows of parallel electrodes deposited on a dielectric substrate covered by a thin insulating coating. The EDS electrodes are connected to a single or multi-phase AC high voltage source to generate an alternating electric field between the electrodes. Such screens have been shown to remove accumulated dust when an alternating voltage is applied. The effect of dust particle size distribution (PSD) on the dust removal efficiency (DRE) of the EDS was analyzed for its application to lunar and Mars missions. Samples of JSC Mars-1 dust simulant were classified into two different particle size distributions. The PSD difference was measured using an Electronic Single Particle Relaxation Time (ESPART) Analyzer. The classified powder was then used to test the performance of electrodynamic screens with two different electrode geometries. The DRE for powder with a count median diameter (CMD) of 5.8 µm was 77.3%, where as for a CMD of 5.2 µm the DRE was 47.1%. Keywords; Dust abatement, electrodynamic, AC electro-kinetic I. INTRODUCTION Mars has a hostile environment for the operation of both stationary and mobile equipment. The layers of fine dust deposited on the surface of Mars gradually reduce the power output of solar panels, which are typically the primary source of power for Mars and lunar missions. Electrodynamic screens (EDS’s) could be used to remove accumulated dust and/or prevent dust accumulation [1]. The EDS has already been tested under low pressure conditions [2] and the dust removal efficiency (DRE) was found to be higher than 80%. An EDS made from the transparent conducting material indium-tin-oxide (ITO), was developed to remove collected dust [3]. This transparent EDS system [4] could be used to extend the life of solar panels for future rover missions to Mars or the Moon. Solar power arrays are currently oversized to offset the effects of dust accumulation. The use of screened solar panels would allow a reduction in the total surface area of solar panels required for a given mission lifetime. This would result in an overall weight reduction in the power supply system and prolong operation. Electrodynamic screening requires no moving parts, uses low output power supplies which can be engineered for reliable operation, and reduces overall mass required for power systems. The experimental data show a dust removal efficiency (DRE, see equation 1) in the range of 85% for charged JSC Mars-1 dust simulant when excited by single phase AC. Multi-phase AC drive can achieve higher DRE levels [3]. Based on data collected by the Opportunity rover from the atmosphere of Mars, the mean diameter of the suspended dust is approximately 3 µm [5]. Our research plan is to test the performance of EDS based dust abatement systems using JSC Mars-1 dust simulant at or near 3 µm mean diameter. Due to the increased adhesion forces for fine particles [6] it is important to test dust removal systems using the appropriate powder PSD. Our next goal is to optimize EDS electrode width and spacing for the appropriate dust particle size distribution (PSD), dust electrostatic charge, operating voltage, excitation waveform shape, and the initial powder loading (surface density). The goal of this research project was to study the effects of PSD on screen performance. To analyze the role of PSD we tested two EDS systems using printed circuit board (PCB) screens using two classified JSC Mars-1 dust simulants and measured the DRE. The early work on electrodynamic traveling-wave systems was done by Masuda et al. [7], Melcher [8], and by Moesner et al. [9, 10]. Previous work related to clearing JSC Mars-1 simulant dust with EDS systems has already established the most effective voltage, waveform, and frequency for the clearing of collected dust [1], has demonstrated the operation of screens at low pressure conditions, in a CO 2 environment [2], and has done initial modeling and analysis for integrating screens into future Mars missions [11]. There is also an application of this technology for microconveyors used for nano-fabrication systems [12]. EDS technology is frequently referred to as AC electro-kinetic in the more recent literature. Jet Propulsion Laboratory (Sponsors) IAS 2005 341 0-7803-9208-6/05/$20.00 © 2005 IEEE