Dust Deposition Mechanisms Research Articles

Prediction of thermal boundary layer thickness and bidirectional effect of dust deposition on the output of photovoltaic modules

Photovoltaic power generation was one of the fastest-growing and most promising forms of solar energy utilization, and dust deposition had an important effect on the output capacity of photovoltaic modules. However, the law and mechanism of dust deposition influence the output performance of the PV modules was still not perfect and deep enough at present. In this paper, the prediction model of the thermal boundary layer thickness (δT) was constructed, and the influence laws of dust deposition on the total attenuation rate (rt) of the top surface and the average temperature (TW) of the backplane surface were explored. Besides, the bidirectional effect of dust deposition on the output performance was researched. The results show that the main components of the dust on the top surface of the PV modules were the quartz or aluminosilicate transported remotely by atmospheric circulation and deposited. The δT at any position of the photovoltaic module decreased with the increase of parallel wind speed (v∥) by the law of −0.49800 power function, and convective heat transfer coefficient (h) changed positively with Re by the law of 0.48752 power function. In the total solar irradiance (G) decreases period and dust deposition amount (A) was 2.024201 g/m2, the influence rate of dust deposition (r) had a maximum value of 0.015363. The dust deposition attenuation rate (rdA) and the temperature gain rate (rtE) all changed positively with A by power function law, and the increase rate of rtE and rdA eventually tends to 0 and infinity, respectively. The theoretical dust removal point of the rooftop PV modules in Hohhot Urban was 5.82661 g/m2.

Experimental Study of Particle Transport and Deposition Distribution over Complex Terrains Based on Spherical Alumina

The transport and deposition of atmospheric particulate matter have attracted significant attention recently due to the increasing frequency of extreme disaster events, such as dust storms, volcanic eruptions, and extensive forest fires. The size distribution of the transported material and the conditions of the land–air interface are dominant factors in comprehending the detrimental potential of atmospheric particulate matter. However, it is still a challenge to understand the mechanism of dust deposition, especially over complex terrain. In an effort to investigate the deposition characteristics of particles over complex terrain, a series of experiments were conducted in a multifunctional environmental wind tunnel. The results show that the wind speed directly above the top of the mild slope model is significantly greater than that in the steep slope model, which indicates that a steep slope has a greater blocking effect on wind fields. At low wind speeds, the average wind speed at the top of the mild slope model is 17.8% higher than that at the top of the steep slope model, and at high wind speeds the average wind speed at the top of the mild slope model is 8.6% higher than that at the top of the steep slope model. The influence trend of the steep slope model and the combination model is basically the same, with both decreasing first and then increasing with the direction of wind velocity. The amount of surface deposition is greatly affected by the location of the feeding point and the microscale characteristics of the surface. In the steep slope model, the deposition is mainly distributed on the windward side, while the leeward side has a small amount of deposition. In the mild slope model, particles are deposited not only on the windward side, but also on the leeward side. The average rate of decline in deposition flux in the steep slope model is 88.4% and 75.1% in the mild slope model. The use of the combination model reduces the particle concentration at the back end compared with the single model. In three different models, the deposition on the windward side was shown to be significantly greater than that on the leeward side of the model. Our work increases understanding of the deposition of coarse dust particles over complex terrain and provides basic data for improving the accuracy of large-region particle transport and deposition simulations.

Experimental and theoretical study on effect of dust deposition on frosting characteristics of fin surface

Since dust accumulates on the fin surface of the outdoor heat exchanger all year round, frost formation inevitably occurs on the fin surface with dust deposition when an air source heat pump is used for heating in winter. However, the effect of dust deposition on frosting characteristics of fin surface has not been clarified. Therefore, visualization experiments were carried out in this paper to study the frosting characteristics on bare and superhydrophobic fin surfaces under different dust deposition levels. Meanwhile, the influence mechanism of dust deposition on frost formation was analyzed theoretically based on phase transition dynamics. The experimental results showed that when the dust deposition on the superhydrophobic fin surface was less than 0.2 g, the dust deposition promoted crystal growth at the initial stage of frost formation, while the frost formation was inhibited when the dust deposition was more than 0.4 g. In the case of bare fin surface, dust deposition always inhibited the frost formation. As the dust deposition mass on the fin surface increased, the thickness and density of the frost layer decreased on both bare and superhydrophobic fin surfaces. In addition, it was worth noting that with the increase of dust deposition, the super hydrophobicity of the superhydrophobic surface was gradually lost. This is not conducive to the practical application of superhydrophobic anti-frosting technology.

Research on dust deposition of PV modules based on three-dimensional numerical simulation and its application in installation parameter optimization

Dust deposition on the surface of photovoltaic (PV) modules leads to a decrease in photoelectric conversion efficiency and output power. To identify the dust deposition factors and laws, scholars have conducted numerous field experiments or numerical simulations. However, few scholars have studied the mechanism of dust deposition with three-dimensional (3D) simulation models. The parameters affecting dust deposition vary in different geographical regions, which limits the applicability of research findings on dust deposition to specific geographical areas. To address these issues, this paper first proposes dust adsorption conditions on the surface of PV modules. Based on the main dust deposition factors, a 3D simulation model for dust deposition is established, and the accuracy and effectiveness of the adsorption conditions and simulation model are verified. Then, with a combined approach of orthogonal experiments and 3D simulation analysis, the main dust deposition factors and laws are analyzed. Finally, regional clustering is conducted by dust deposition factors, and the simulation results are applied to the regional optimization of installation parameters. The case study results show that the PV modules have a maximum power generation of 231.91 kWh with an optimal installation angle of 17° and an installation height of 0.5 m in the I category region.

Estimation of the desert dust balance and its relationship with environmental factors in the southern Baja California Peninsula

The emission, transport, and deposition of desert dust are influenced by environmental factors evaluated mainly as a function of precipitation, air temperature, and wind. The present study estimates the desert dust balance and its relationship with environmental factors for the period 1981–2020 in the Baja California Sur region, Mexico. Monthly data on wind, air temperature, precipitation, dust emission and deposition from in situ measurements, reanalysis, satellite estimates and a numerical parameterization scheme are used. First, the in-situ time series were reconstructed with a non-linear principal component analysis based on an autoassociative neural network. We then evaluated the performance of the satellite estimates and the reanalysis data using the matching technique, after which we quantified the dust emission in three source zones. To estimate the state of the climate, we obtained the annual cycle of monthly climatologies, and yearly averages. The effect of climate on the dust budget is estimated by means of non-parametric associations between the variables of interest. Finally, we estimate climate trends using Pettitt, Modified Man-Kendall and Theil-Sen tests. The results show that the data sets used represent the mean and variability of in situ measurements. There are three seasons with transitional periods for precipitation and air temperature. The wind shows a longitudinal west–east gradient. Its maximum intensity is from April to September. Northern zone was dominated by highest emissions. Dry deposition mechanism was the most representative. Emissions and dry deposition are controlled by wind intensity and precipitation, while precipitation controls wet deposition. The Pettitt test showed that abrupt changes in the time series coincide with periods where positive sunspot anomalies converge with negative PDO and SOI anomalies. Finally, trend analyses identified a temporal broadening of the dry season, warmer winters, and summers with increases of ~ 0.02 °C, predominantly increasing trends in dust emissions and wind intensity, and a progressive decrease in dust deposition mechanisms.

Construction of an occupational-dust hazard testing platform: An experimental study on the deposition mechanisms

This study aimed to understand the influence of dust concentrations and environmental exposure on the mechanism of dust deposition in the human body following inhalation. Using a self-developed occupational dust hazard testing platform, the particle size and mass of dust in the environment and the dust inhaled by a bionic throat were measured under different conditions. The experimental results showed that an increase in dust concentration in the experimental area resulted in an increase in the size of the dust particles, particularly the absolute value of small-sized dust particles. The range of variation of the particle size of dust inhaled by the bionic throat was less than 25%, and the mass of dust inhaled exhibited a positive linear trend. When the dust concentration was fixed, an increase in the dust exposure time resulted in a gradual decrease in the dust particle size. When the dust exposure time reached 60 s, the particle size of the dust inhaled by the bionic throat remained constant, and the mass of the dust inhaled exhibited an increasing linear trend. With an increase in altitude, the dust concentrations in the experimental area gradually increased, whereas the dust particle size gradually decreased. The mass of dust inhaled by the bionic throat was represented by a quadratic power function. The results provide effective theoretical support for the prevention and control of dust originating from coal mines.

Study on the formation and evolution mechanism of dust deposition on solar photovoltaic panels

Study on the formation and evolution mechanism of dust deposition on solar photovoltaic panels

Review on dust deposition and cleaning methods for solar PV modules

Dust accumulation significantly affects the solar PV(Photovoltaic) performance, resulting in a considerable decrease in output power, which can be reduced by 40% with the dust of 4 g/m2. Understanding the dust deposition characteristics of PV modules can provide theoretical support for selecting dust cleaning methods and formulating cleaning strategies. This paper introduced the factors affecting dust accumulation and presented the research status of dust deposition mechanisms. Moreover, the dust cleaning methods were discussed and compared. In future research, a comprehensive particle deposition model including surface energy and other factors could be established to explore the dust accumulation mechanism. Additionally, investigating the particle deposition condition to determine the deposition of particles is beneficial to understanding the dust accumulation characteristics and predicting the dust accumulation amount. Compared with mechanical cleaning methods, the cleaning effect of electrostatic (cleaning efficiency can reach 90%), coating, and acoustic wave methods is superior. If the three methods can be combined, using an electrostatic or coating method to remove small particles and acoustic waves to remove large particles is a promising approach.

Mathematical justification of the mechanism of dust deposition by electrofilters for improving working conditions of poultry farm workers

The aim of the research is to reduce the concentration of dust in poultry houses by means of dust deposition by means of electrostatic precipitators. The objectives of the study include ensuring the improvement of working conditions for workers in poultry farms by reducing the dust content of the air; analysis of methods of air purification from industrial dust in poultry buildings; proposing the most effective way to clean the air from industrial dust in poultry buildings based on the analysis of existing methods and technical means. Analysis of the existing methods and technical means for cleaning the air environment of production facilities in poultry farming revealed that the most effective devices for reducing dust levels are electrostatic precipitators based on the action of corona discharge. But currently patented electrostatic precipitators have a limited scope. This is due to the fact that electrostatic precipitators provide high efficiency of dust removal with significant overall dimensions of these devices. The technical solution to this problem is the use of cylindrical multisection electrostatic precipitators, in which all corona and collecting electrodes have the shape of a cylinder and are arranged radially, alternately following one after the other. As practical results have shown, this design cleans significant volumes of air in a better quality, without the need for reconstruction of technological equipment, expansion of production areas and freeing up additional space.

Experimental measurement and Numerical Simulation of Particle Deposition on super–hydrophobic surface

Airborne dust deposition on a large number of energy devices would cause serious efficiency and lifetime reduction, such as solar photovoltaic panels, heat exchanger surfaces and fan blades. Mechanicalor manual cleaning using water is still the main method of mitigating dust deposition damage on theserelated energy equipment, which is commonly expensive and frequent. As a kind of self-cleaningmaterial,super–hydrophobic coating may become a new effective way to mitigating the dust deposition issue. Super–hydrophobic coatings with low surface energy and unique micro-nano secondary structure can significantly reduce dust deposition rate. However, mechanism of dust deposition on super-hydrophobic surfaces remains unclear. Thus it is difficult to develop high performance self-cleaning coating. This paper aims to investigate dust deposition behaviors and mechanisms on super-hydrophobic surface by experimental measurement and numerical simulation. Lattice Boltzmann Method-Discrete Particle Method (LBM–DPM) will be developed to predict dust particle deposition process including settling, collision adhesion and rebound behaviors. The mechanisms and interactions between coating surface energy, particle characteristics, particle incident velocity and particle adhesion or rebound behavior will be studied carefully. The findings and results may be useful to guide the development of high performance self-cleaning super– hydrophobic coating.

IMPROVING THE EFFICIENCY OF COLLECTING CHAMBERS FOR CAPTURE OF METALLURGICAL DUST

The main scientifi c and practical results improve the efficiency of the cameras for recycling of metallurgical dust through the development and introduction of the units of new generation capable to improve environmental protection and working conditions and to reduce the loss of useful product. The article describes analysis and evaluation of technologies and means of improving the efficiency of dust collection chambers. A theoretical study of the mechanism of dust deposition in the collecting chamber and the results of laboratory studies of its effi ciency with fi ber curtains and inertial deposition of the aerosol on the fi ber curtain are considered. The authors have proposed the new mechanism for dust deposition in the collection chamber and the infl uence of the electric charge on the particle and fi ber deposition effi ciency of dust in the camera. The expressions for the degree of inertia and diff usion deposition of dust particles in the thin cylindrical fi ber and regular system of vertical fi bers were determined.

Research on the Dust Deposition and Corrosion Problems in Heating Surface at the Rear of Oil-Fired Boiler

Abstract. Aim at the problems of acid corrosion and dust blocking in heating surface at the rear of heating surface for oil-fired boiler, which comes from industrial production practice, a analysis in detail is carried on the reason of the acid corrosion formation and the mechanism of dust deposition, base on that are some preliminary solutions put forward according to the work practice. It can be proved to have a good effect on the safety and energy saving during the use and maintenance process of the oil-fired boiler and it can also provide a reference to the enrichment and perfection about the correlation theory of the oil-fired boiler.

Dust Deposition in Granular Bed Filters: Theories and Experiments

The paper reviews the status of granular bed dust filtration theory and its experimental verification. First, works on fluid flow around a single sphere and their relevance to filtration theory are reviewed and solutions of flows in packed and fludized beds of granules are presented. Solutions for creeping flows, potential flows, intermediate and high Reynolds number flows are discussed in relation to filtration theory. Then the various dust deposition mechanisms and their development are presented. Theories based on inertia, diffusion, and other mechanisms are reviewed. Some of the latest theories combining the different effects are described. Experimental data from the literature are presented and compared with various theoretical models.