scholarly journals Design and Test of a Multi-Axis Acoustic-Levitation Device for Non-Contact Dust Removal from Precision Instruments

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Yudi Niu ◽  
Yifan Pu ◽  
Xiaoqi Che ◽  
Mei Wang
Keyword(s):  
Dust Removal ◽  
Dust Particles ◽  
Acoustic Levitation ◽  
Particle Properties ◽  
Modeling Simulation ◽  
Voltage Output ◽  
Demonstration Experiment ◽  
Industrial Solution ◽  
Light Absorbance ◽  
Industrial Problem

To resolve the issues of the conventional dust removing method, such as electrostatic suspension and direct wiping with special lens paper, which can cause damage to precision instruments and their dependence on specific dust particle properties, we present a novel acoustic-levitation device design which incorporates an initial design of a multi-axis levitation device by Marzo. A. with our enhancement model based on the variation of transducers numbers and their spacing to achieve the dust removing efficiency and feasibility in real dust removal process. In this work, modeling simulation in COMSOL Multiphysics and light absorbance experiment are performed to evaluate the distribution of acoustic fields, trajectory of dust particles, and dust removing efficiency. With the manufactured device based on our design, the varying factors are characterized that may influence the removing efficiency when output voltage generated onto motor driven board is altered. Experiment shows 27.5 V is the most efficient voltage output with highest dust removal proportion in actual removing operations. The study demonstrates our design can achieve higher dust removing efficiency comparing to conventional methods. Whereas our design serves the purpose to solve a practical industrial problem, this paper also shows how it can be taken into the classroom as an demonstration experiment, providing an animated way to visualize the nodes and antinodes by the levitation position of particles, which help the students to not only understand the physical properties of standing waves, but also the connection from a classroom lab to an industrial solution.

Optical Modeling of Reflectivity Loss Caused by Dust Deposition on CSP Mirrors and Restoration of Energy Yield by Electrodynamic Dust Removal

2014 ◽  
Author(s):  
Jeremy Stark ◽  
Julius Yellowhair ◽  
John N. Hudelson ◽  
Mark Horenstein ◽  
Malay Mazumder
Keyword(s):  
Power Plants ◽  
Specular Reflection ◽  
Mie Scattering ◽  
Dust Removal ◽  
Dust Particles ◽  
Energy Yield ◽  
Dust Deposition ◽  
Optical Modeling ◽  
Specular Reflectivity ◽  
Semi Arid

For large scale CSP power plants, vast areas of land are needed in deserts and semi-arid climates where uninterrupted solar irradiance is most abundant. These power facilities use large arrays of mirrors to reflect and concentrate sunlight onto collectors, however, dust deposition on the optical surfaces causes obscuration of sunlight, resulting in large energy-yield losses in solar plants. This problem is compounded by the lack of natural clean water resources for conventional cleaning of solar mirrors, often with reflective surface areas of large installations exceeding a million square meters. To investigate the application of transparent electrodynamic screens (EDS) for efficient and cost effective dust removal from solar mirrors, both optical modeling and experimental verifications were performed. Prototype EDS-integrated mirrors were constructed by depositing a set of parallel transparent electrodes into the sun-facing surface of solar mirrors and coating electrodes with thin transparent dielectric film. Activation of the electrodes with a three-phase voltage creates an electrodynamic field that charges and repels dust electrostatically by Coulomb force and sweeps away particles by a traveling electrodynamic wave. We report here brief discussions on (1) rate of deposition and the properties of dust with respect to their size distribution and chemical composition in semi-arid areas of the southwest US and Mojave Desert and their adhesion to solar mirrors, (2) optical models of: (a) specular reflection losses caused by scattering and absorption by dust particles deposited on the surface based on Mie scattering theory, and (b) reflection loss by the integration of EDS on the mirror surface, computed by FRED ray-tracing model. The objective is to maintain specular reflectivity of 90% or higher by frequent removal of dust by EDS. Our studies show that the incorporation of transparent EDS would cause an initial loss of 3% but would be able to maintain specular reflectivity more than 90% to meet the industrial requirement for CSP plants. Specular reflection measurements taken inside a climate controlled environmental chamber show that EDS integration can restore specular reflectivity and would be able to prevent major degradation of the optical surface caused by the deposition of dust.

Simulation of dust-air flow near a rotating disk cylinder suction unit

2019 ◽  
pp. 70-74
Author(s):  
A. B. Goltsov ◽  
K. I. Logachev ◽  
O. A. Averkova ◽  
V. A. Tkachenko
Keyword(s):  
Computer Model ◽  
Lateral Surface ◽  
Cylindrical Surface ◽  
Air Flow ◽  
Rotating Disk ◽  
Rotating Cylinder ◽  
Dust Removal ◽  
Dust Particles ◽  
Operating Parameters

A dust-air flow near a vertically located rotating cylinder with a suction unit located on the lateral surface was investigated. A computer model of this suction unit was developed, the effect of disks mounted on a cylindrical surface on the intake air flow and on the capture of dust particles in the suction unit, as well as the design and operating parameters of the proposed disk cylindrical suction (DCC), which reduce the dust loss. The influence of the size and number of discs, aspiration air flow on dust removal has been established. This design of a rotating disk cylinder suction unit can be used in aspiration shelters with the function of a dust-collecting chamber. Ill. 6. Ref. 15.

scholarly journals Efficiency of the deposition mode ice nucleation on mineral dust particles

2006 ◽  
Vol 6 (1) ◽  
pp. 1539-1577 ◽  
Author(s):  
O. Möhler ◽  
P. R. Field ◽  
P. Connolly ◽  
S. Benz ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Dust Particle ◽  
Formation Rate ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Saturation Ratio ◽  
Particle Properties ◽  
Aerosol Chamber ◽  
Aerosol Fraction ◽  
Takla Makan Desert ◽  
Deposition Mode

Abstract. The deposition mode ice nucleation efficiency of various dust aerosols was investigated at cirrus cloud temperatures between 196 K and 223 K using the aerosol chamber facility AIDA (Aerosol Interaction and Dynamics in the Atmosphere). Arizona test dust (ATD) as a reference material and two dust samples from the Takla Makan desert in Asia (AD1) and Sahara (SD2) were used for the experiments at simulated cloud conditions. The dust particle sizes were almost lognormally distributed with mode diameters between 0.3 µm and 0.5 µm and geometric standard deviations between 1.6 and 1.9. Deposition ice nucleation was most efficient on ATD particles with ice-active particle fractions of about 0.6 and 0.8 at an ice saturation ratio Si<1.15 and temperatures of 223 K and 209 K, respectively. No significant change of the ice nucleation efficiency was found in up to three subsequent cycles of ice activation and evaporation with the same ATD aerosol. The desert dust samples SD2 and AD1 showed a significantly lower fraction of active deposition nuclei, about 0.25 at 223 K and Si<1.35. For all samples the ice activated aerosol fraction could be approximated by an exponential equation as function of Si. This formulation of ice activation spectra may be used to calculate the formation rate of ice crystals in models, if the number concentration of dust particles is known. More experimental work is needed to quantify the variability of the ice activation spectra as function of the temperature and dust particle properties.

scholarly journals Environmental dust removal from inclined hydrophobic glass surface: avalanche influence on dynamics of dust particles

RSC Advances ◽  
2018 ◽  
Vol 8 (59) ◽  
pp. 33775-33785 ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Abdullah Al-Sharafi ◽  
Haider Ali ◽  
Nasser Al-Aqeeli ◽  
Hussain Al-Qahtani ◽  
...  
Keyword(s):  
Glass Surface ◽  
Dust Removal ◽  
Dust Particles ◽  
Transparent Glass ◽  
Optically Transparent ◽  
Glass Surfaces

The removal of environmental dust particles from optically transparent glass surfaces is considered, and the dynamics of the dust particles on the inclined hydrophobic glass surface is examined.

scholarly journals Stretchable Hydrophobic Surfaces and Self-Cleaning Applications

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bekir Sami Yilbas ◽  
Ghassan Hassan ◽  
Hussain Al-Qahtani ◽  
Naser Al-Aqeeli ◽  
Abdullah Al-Sharafi ◽  
...  
Keyword(s):  
Contact Angle ◽  
Water Droplet ◽  
Dust Removal ◽  
Dust Particles ◽  
Mass Ratio ◽  
Water Droplets ◽  
Surface Wetting ◽  
Hydrophobic Surfaces ◽  
Removal Mechanisms ◽  
Nano Size

Abstract Hydrophobizing of stretchable elastomer surfaces is considered and the reversible behavior of the resulting surface wetting state is examined after stretching and relaxing the hydrophobized samples. The environmental dust are analyzed in terms of elemental constitutes and size, and the dust pinning on the hydrophobized surface is measured. The dust removal mechanisms, by the water droplets on the hydrophobized surface, are investigated. We demonstrated that deposition of functionalized nano-size silica units on the elastomer surface gives rise to hydrophobicity with 135° ± 3° contact angle and low hysteresis of 3° ± 1°. Stretching hydrophobized elastomer surface by 50% (length) reduces the contact angle to 122° ± 3° and enhances the hysteresis to 6° ± 1°. However, relaxing the stretched sample causes exchanging surface wetting state reversibly. Water droplet rolling and sliding can clean the dusty hydrophobized surface almost 95% (mass ratio of the dust particles removed). Droplet puddling causes striations like structures along the droplet path and close examination of the few residues of the dust reveals that the droplet takes away considerably large amount of dust from surface.

scholarly journals Efficiency of the deposition mode ice nucleation on mineral dust particles

2006 ◽  
Vol 6 (10) ◽  
pp. 3007-3021 ◽  
Author(s):  
O. Möhler ◽  
P. R. Field ◽  
P. Connolly ◽  
S. Benz ◽  
H. Saathoff ◽  
...  
Keyword(s):  
Dust Particle ◽  
Formation Rate ◽  
Ice Nucleation ◽  
Dust Particles ◽  
Particle Properties ◽  
Mineral Particles ◽  
Aerosol Fraction ◽  
Homogeneous Freezing ◽  
Takla Makan Desert ◽  
Deposition Mode

Abstract. The deposition mode ice nucleation efficiency of various dust aerosols was investigated at cirrus cloud temperatures between 196 and 223 K using the aerosol and cloud chamber facility AIDA (Aerosol Interaction and Dynamics in the Atmosphere). Arizona test dust (ATD) as a reference material and two dust samples from the Takla Makan desert in Asia (AD1) and the Sahara (SD2) were used for the experiments at simulated cloud conditions. The dust particle sizes were almost lognormally distributed with mode diameters between 0.3 and 0.5 μm and geometric standard deviations between 1.6 and 1.9. Deposition ice nucleation was most efficient on ATD particles with ice-active particle fractions of about 0.6 and 0.8 at an ice saturation ratio Si<1.15 and temperatures of 223 and 209 K, respectively. No significant change of the ice nucleation efficiency was found in up to three subsequent cycles of ice activation and evaporation with the same ATD aerosol. This indicates that the phenomenon of preactivation does not apply to ATD particles. The desert dust samples SD2 and AD1 showed a significantly lower fraction of active deposition nuclei, about 0.25 at 223 K and Si<1.35. For all samples the ice activated aerosol fraction could be approximated by an exponential equation as function of Si. This indicates that deposition ice nucleation on mineral particles may not be treated in the same stochastic sense as homogeneous freezing. The suggested formulation of ice activation spectra may be used to calculate the formation rate of ice crystals in models, if the number concentration of dust particles is known. More experimental work is needed to quantify the variability of the ice activation spectra as function of the temperature and dust particle properties.

scholarly journals Synergistic removal of dust using the wet flue gas desulfurization systems

2019 ◽  
Vol 6 (7) ◽  
pp. 181696 ◽  
Author(s):  
Qirong Wu ◽  
Min Gu ◽  
Yungui Du ◽  
Hanxiao Zeng
Keyword(s):  
Removal Efficiency ◽  
Flue Gas ◽  
Power Plants ◽  
Flue Gas Desulfurization ◽  
Dust Removal ◽  
Dust Particles ◽  
Experimental Conditions ◽  
Collision Model ◽  
Sieve Tray ◽  
Spray Scrubber

Coal is still a major energy source, mostly used in power plants. However, the coal combustion emits harmful SO 2 and fly ash. Wet flue gas desulfurization (WFGD) technology is extensively used to control SO 2 emissions in power plants. However, only limited studies have investigated the synergistic dust removal by the WFGD system. Spray scrubbers and sieve-tray spray scrubbers are often used in WFGD systems to improve the SO 2 removal efficiency. In this study, the synergistic dust removal of WFGD systems for a spray scrubber and a sieve-tray spray scrubber was investigated using the experimental and modelling approaches, respectively. For the spray scrubber, the influence of parameters, including dust particle diameters and inlet concentrations of dust particles, and the flow rates of flue gas and slurry of limestone/gypsum on the dust removal efficiency, was investigated. For the sieve-tray spray scrubber, the influence of parameters such as the pore diameter and porosity of sieve trays on the dust removal efficiency was examined. The study found that the dust removal efficiency in the sieve-tray spray scrubber was approximately 1.1–10.6% higher than that of the spray scrubber for the same experimental conditions. Based on the parameters investigated and geometric parameters of a scrubber, a novel droplets swarm model for dust removal efficiency was developed from the single droplet model. The enhanced dust removal efficiency of sieve tray was expressed by introducing a strength coefficient to an inertial collision model. The dust removal efficiency model for the sieve-tray spray scrubber was developed by combining the droplets swarm model for the spray scrubber with the modified inertial collision model for the sieve tray. The results simulated using both models are consistent with the experimental data obtained.

UV/VIS Characterization and FT-IR Analysis of Harmattan Dust across Sub-Sahara Region of Africa

2021 ◽  
Vol 14 (1) ◽  
pp. 1-17
Keyword(s):  
Dust Particles ◽  
Hydroxyl Group ◽  
Trade Wind ◽  
North East ◽  
Out Of Plane ◽  
Ft Ir ◽  
Ir Analysis ◽  
Suspended Dust ◽  
Uv Visible ◽  
Light Absorbance

Abstract: The suspended dust particles that blow across Nigeria as a result of north-east trade wind emanating from the Sahara desert annually are locally referred to as Harmattan. Suspended dust samples were collected across ten different stations in Nigeria; namely: Maiduguri (11º49'N, 13º09'E), Potiskum (11º43'N, 11º02'E), Bauchi (10º17'N, 09º 48'E), Jos (9º55'N, 8º55'E), Lafia (08º49'N, 07º50'E), Abuja (09º09'N, 07º11'E), Minna (9º36'N, 06º35'E), Ilorin (8º36'N, 4º 35'E), Oyo (8º12'N, 3º42'E) and Iwo (7º63'N, 4º19'E) and analyzed using Fourier Transform Infrared (FT-IR) and UV-Visible spectroscopy. The quantitative, qualitative and optical characterization analyses were carried out on all the samples collected across all the stations considered, in order to obtain the functional groups and some elements present in the samples. The FT-IR spectra peaks show that the transmittance waveband from 3337.8 cm-1 to 3291.2 cm-1 corresponds to the Hydroxyl group, H-bonded OH stretch in plane and out of plane bonds for all the stations considered. These bonds represent the presence of transition metals and unsaturated bonds found in the samples, which include K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Mo, As, Zr, Pb, V, Sr, Cr and Ce. The samples collected across all stations have maximum UV absorbance peaks at around 210 nm waveband and weak visible light absorbance peaks (orange – red spectra) around 620 nm and 700 nm. The study concluded that the transmittance waveband, the waveband absorbance peaks and the elemental composition of the dust samples analyzed vary from station to station. This study will however recommend that further study be made for the purpose of environmental awareness. Keywords: Harmattan, Particles, FT-IR, UV, Dust.

Resonance methods for the characterization of dust particles in plasmas

2016 ◽  
Vol 82 (3) ◽  
Author(s):  
Hendrik Jung ◽  
Franko Greiner ◽  
Oguz Han Asnaz ◽  
Jan Carstensen ◽  
Alexander Piel
Keyword(s):  
Dynamic Response ◽  
Resonance Method ◽  
Precision Measurements ◽  
Dust Particles ◽  
Laboratory Plasma ◽  
Particle Properties ◽  
External Perturbations ◽  
Technical Requirements

The fundamentals of the ‘resonance method’ are presented. The method relies on evaluating the dynamic response of one or more dust particles in the sheath of a laboratory plasma to small external perturbations. It allows one to make in situ high-precision measurements of particle properties. It is shown that the particle mass and charge and the strength of the interaction between two particles can be measured. Technical requirements, limitations and application examples are presented and discussed.

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