Editorial

3 pages, 190 KiB

Open AccessEditorial

Special Issue “Recent Developments on Functional Coatings for Industrial Applications, Volume II”

by Luigi Calabrese and Edoardo Proverbio

Coatings 2023, 13(3), 593; https://doi.org/10.3390/coatings13030593 - 10 Mar 2023

Viewed by 819

“Recent Developments on Functional Coatings for Industrial Applications, Volume II” addresses the provision of further insights into new and emerging research assets concerning the design, manufacturing, characterization and optimization of functional coatings for industrial applications. The aim of this Issue is to further [...] Read more.

“Recent Developments on Functional Coatings for Industrial Applications, Volume II” addresses the provision of further insights into new and emerging research assets concerning the design, manufacturing, characterization and optimization of functional coatings for industrial applications. The aim of this Issue is to further contribute to the improvement of knowledge on functional coatings synthesis, characterization and tailoring, emphasizing its emerging industrial applicability in several industrial fields. The multidisciplinary nature of the theme represents a further stimulus aimed at enhancing the applicative importance and the technological versatility of the engineering design of functional surfaces. A multidisciplinary approach will act as a further stimulus in encouraging researchers to exploit suitably the applicative relevance and adaptability of functional coating and surface engineering design and tailoring. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

Research

Jump to: Editorial

14 pages, 7634 KiB

Open AccessArticle

The Icing Characteristics of a 1.5 MW Wind Turbine Blade and Its Influence on the Blade Mechanical Properties

by Yexue Han, Zhen Lei, Yuxiao Dong, Qinghui Wang, Hailin Li and Fang Feng

Coatings 2024, 14(2), 242; https://doi.org/10.3390/coatings14020242 - 19 Feb 2024

Viewed by 707

Abstract

Ice accumulation significantly impacts the mechanical properties of wind turbine blades, affecting power output and reducing unit lifespan. This study explores the icing characteristics and their effects on a 1.5 megawatt (MW) wind turbine blade’s mechanical properties under various conditions, including wind speeds [...] Read more.

Ice accumulation significantly impacts the mechanical properties of wind turbine blades, affecting power output and reducing unit lifespan. This study explores the icing characteristics and their effects on a 1.5 megawatt (MW) wind turbine blade’s mechanical properties under various conditions, including wind speeds of 5 m per second (m/s) and 10 m per second, temperatures of −5 degrees centigrade (°C) and −10 degrees centigrade, and different liquid water contents, by using icing wind tunnel tests and structural statics analysis. The research reveals that ice predominantly forms in an irregular pattern on the leading edge of the blade. It is easy to produce corner ice and ice skating when the icing temperature and wind speed are higher, and the icing surface is rougher. When the other conditions remain unchanged, the decrease in temperature, an increase in wind speed, or a rise in liquid water content all lead to an increase in the average thickness of icing and the volume of icing at the leading edge, with the effect of the wind speed on the two being 147.8% and 147.9%, the effect of the liquid water content on the two being 39.9% and 53.5%, and the effect of the temperature on the two being 24.6% and 13.2%. The study finds that the blade tip experiences the maximum displacement in both iced and non-iced states, although the positions of peak equivalent stress and strain vary. The above study will also provide references for the design of new wind turbine blades and the anti-icing maintenance of wind turbine generator sets. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Figure 1

13 pages, 4006 KiB

Open AccessArticle

The Influence of Angle of Attack on the Icing Distribution Characteristics of DU97 Blade Airfoil Surface for Wind Turbines

by Chuanxi Wang, Weirong Lin, Xuefeng Lin, Tong Wu, Zhe Meng, Anmin Cai, Zhi Xu, Yan Li and Fang Feng

Coatings 2024, 14(2), 160; https://doi.org/10.3390/coatings14020160 - 25 Jan 2024

Cited by 1 | Viewed by 657

Abstract

This study explores the influence of angle of attack (AOA) on the icing distribution characteristics of asymmetric blade airfoil (DU97) surfaces for wind turbines under icing conditions by numerical simulation. The findings demonstrate a consistence between the simulated ice shapes and experimental data. [...] Read more.

This study explores the influence of angle of attack (AOA) on the icing distribution characteristics of asymmetric blade airfoil (DU97) surfaces for wind turbines under icing conditions by numerical simulation. The findings demonstrate a consistence between the simulated ice shapes and experimental data. The ice thickness distribution on the lower surface of the leading edge exhibits a trend of first rising and then declining along the chord direction while showing a gradually decreasing trend on the upper surface. The ice distribution range on the upper surface of the trailing edge is broader than that on the lower surface. The peak ice thickness at the trailing edge rises significantly as AOA increases from 5° to 10°, and at the leading edge raises dramatically at droplet sizes of 30–40 μm and wind speeds of 5–10 m/s. The peak ice thickness is more significantly influenced by AOA than by ambient temperature due to the combined effect of airflow characteristics induced by AOA and latent heat (phase change) and sensible heat (thermal convection and thermal radiation) caused by ambient temperature. The findings offer valuable insights into the flow and heat transfer physics, and can operate as references for wind turbine anti/de-icing technology. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Figure 1

18 pages, 8425 KiB

Open AccessArticle

An Experimental Study on Blade Surface De-Icing Characteristics for Wind Turbines in Rime Ice Condition by Electro-Thermal Heating

by Xiaojuan Li, Haodong Chi, Yan Li, Zhi Xu, Wenfeng Guo and Fang Feng

Coatings 2024, 14(1), 94; https://doi.org/10.3390/coatings14010094 - 10 Jan 2024

Viewed by 960

Abstract

Wind turbines in cold and humid regions face significant icing challenges. Heating is considered an efficient strategy to prevent ice accretion over the turbine’s blade surface. An ice protection system is required to minimize freezing of the runback water at the back of [...] Read more.

Wind turbines in cold and humid regions face significant icing challenges. Heating is considered an efficient strategy to prevent ice accretion over the turbine’s blade surface. An ice protection system is required to minimize freezing of the runback water at the back of the blade and the melting state of the ice on the blade; the law of re-freezing of the runback water is necessary for the design of wind turbine de-icing systems. In this paper, a wind tunnel test was conducted to investigate the de-icing process of a static heated blade under various rime icing conditions. Ice shapes of different thicknesses were obtained by spraying water at 5 m/s, 10 m/s, and 15 m/s. The spray system was turned off and different heating fluxes were applied to heat the blade. The de-icing state and total energy consumption were explored. When de-icing occurred in a short freezing time, the ice layer became thin, and runback water flowed out (pattern I). With an increase in freezing time at a low wind speed, the melting ice induced by the dominant action of inertial force moved backward due to the reduction in adhesion between the ice and blade surface (pattern II). As wind speed increased, it exhibited various de-icing states, including refreezing at the trailing edge (pattern III) and ice shedding (pattern IV). The total energy consumption of ice melting decreased as the heat flux increased and the ice melting time shortened. At 5 m/s, when the heat flux was q = 14 kW/m², the energy consumption at E_A at t_δ = 1 min, 5 min, and 7 min were 0.33 kJ, 0.55 kJ, and 0.61 kJ, respectively. At 10 m/s, when the heat flux was q = 14 kW/m², the energy consumption at E_A at t_δ = 1 min, 3 min, and 5 min were 0.77 kJ, 0.81 kJ, and 0.80 kJ, respectively. Excessive heat flow density increased the risk of the return water freezing; thus, the reference de-icing heat fluxes of 5 m/s and 10 m/s were 10 kW/m² and 12 kW/m², respectively. This paper provides an effective reference for wind turbine de-icing. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Graphical abstract

9 pages, 6642 KiB

Open AccessArticle

Properties of Superhydrophobic and Acid–Alkali-Resistant Polyester Fabric Produced Using Plasma Processing

by Bing Zhao, Liyun Xu, Panpan Lin, Hua Zhang, Xiangyu He, Tao Ji and Yu Zhang

Coatings 2023, 13(12), 2007; https://doi.org/10.3390/coatings13122007 - 26 Nov 2023

Viewed by 975

Abstract

During the processes of production, storage, transportation and use of hazardous chemicals, acid–alkali corrosive liquid spatter and leakage would cause serious casualties. In order to protect the lives and health of staff, the surface of fabrics should be treated to obtain hydrophobicity and [...] Read more.

During the processes of production, storage, transportation and use of hazardous chemicals, acid–alkali corrosive liquid spatter and leakage would cause serious casualties. In order to protect the lives and health of staff, the surface of fabrics should be treated to obtain hydrophobicity and acid–alkali resistance. In this paper, polyester fabric was used as the base cloth, and polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) micro-powder were used as the functional materials to fabricate waterproof and breathable fabric with good acid–alkali resistance using a method of plasma pretreatment-impregnation- and plasma-induced crosslinking. The effects of PDMS, PTFE powder and plasma-induced crosslinking on the surface and physical and chemical properties of fabric were investigated. It was found that the use of PDMS and PTFE powder had little effect on the mechanical and wearing comfort properties. However, it could significantly improve the acid–alkali resistance, as the liquid repellent rate of the treated fabric surface was higher than 80%, and the penetration index was lower than 2%. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Figure 1

17 pages, 9247 KiB

Open AccessArticle

Wear Evolution on PVD Coated Cutting Tool Flank and Rake Explained Considering Stress, Strain and Strain-Rate Dependent Material Properties

by Antonios Bouzakis, Georgios Skordaris, Emmanouil Bouzakis, Konstantinos-Dionysios Bouzakis and Dimitrios Tsakalidis

Coatings 2023, 13(12), 1982; https://doi.org/10.3390/coatings13121982 - 22 Nov 2023

Viewed by 575

Abstract

Impact loads developed on a tool cutting edge when milling into a workpiece material are prevailing metrics for explaining coating fatigue failure and the subsequent tool-wear evolution. For predicting related stress and strain fields in the compound coating-substrate, stress, strain, and strain-rate, dependent [...] Read more.

Impact loads developed on a tool cutting edge when milling into a workpiece material are prevailing metrics for explaining coating fatigue failure and the subsequent tool-wear evolution. For predicting related stress and strain fields in the compound coating-substrate, stress, strain, and strain-rate, dependent material properties are required. The attainment of such data is briefly described in the paper. Considering these data, the occurring strains in the cutting edge at various entry impact durations, i.e., strain rates, were calculated and compared with fatigue-critical strains. In this way, the wear phenomena causing the coating failure on the flank and rake during milling were clarified. The attained results were also correlated to corresponding ones in turning, where the dynamic loads of the cutting edge are comparably negligible. The conducted investigations showed that the fatigue-critical strains strongly diminish, when the relevant strain rates increase; thus, leading to a remarkable tool-life reduction. This happens, because the increase of the strain-rate restricts the time for the dislocations movements; thus, regions with stress concentrations occur, deteriorating the material ductility, increasing its brittleness, and diminishing the fatigue critical strains. In cutting operations, where the coating fatigue is the main wear factor, the tool-life can be predicted considering these phenomena. In the paper, relevant experimental analytical procedures are introduced. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Graphical abstract

20 pages, 6379 KiB

Open AccessArticle

Effects and Consequences of an Alkali-Induced Cathodic Environment on Coating Aging

by Krystel Pélissier, Erwan Diler, Manuel Dossot, Cédric Carteret, Jean Vittonato, François Castillon, Sylvain Fontaine, Thierry Kerzerho, Nicolas Larché and Patrice Lucas

Coatings 2023, 13(11), 1949; https://doi.org/10.3390/coatings13111949 - 15 Nov 2023

Viewed by 871

Abstract

The use of organic coatings in conjunction with cathodic protection (CP) for buried structures is the usual method for protecting steel against corrosion. When the organic coating loses its protective ability, regardless of the reason, the CP becomes the active protection, leading to [...] Read more.

The use of organic coatings in conjunction with cathodic protection (CP) for buried structures is the usual method for protecting steel against corrosion. When the organic coating loses its protective ability, regardless of the reason, the CP becomes the active protection, leading to a specific local environment. This environment can be characterized by high alkalinity, which can be detrimental for the coated structure, either by weakening the steel–coating interface or by the chemical aging of the coating. Thus, the coating must be compatible with CP and able to sustain aging under an alkaline environment. In this study, the susceptibility to alkaline aging and its consequences in regards to coating performance have been investigated for two commercial coatings used for buried structures—fusion bonded epoxy (FBE) and liquid epoxy (LE)—in free membrane and coated steel configurations. The results showed a clear impact of alkaline aging on the studied LE, leading to a significant reduction in coating resistance and ultimately, failure of the steel–coating interface, whereas the studied FBE remained stable. The presented results relate to a precise formulation of LE and FBE; however, the proposed chemical method appears to be relevant and shows the necessity of considering such specific aging results for coating specifications and improvements. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Figure 1

16 pages, 5150 KiB

Open AccessArticle

Fabrication and Characterization of TiO₂ Coatings on 304 Stainless-Steel Substrate for Efficient Oil/Water Separation

by Jose Sico, Benjamin Tang, Dayana Flores, Roy Mouawad, Rheyana Punsalan, Yong X. Gan and Mingheng Li

Coatings 2023, 13(11), 1920; https://doi.org/10.3390/coatings13111920 - 09 Nov 2023

Viewed by 1175

Abstract

Oil spill accidents have been a prevalent threat to the environment. To aid in clean-up efforts, a stainless-steel filter with a hydrophilic and oleophobic coating was fabricated for efficient and affordable oil/water separation. Two solutions were used to deposit the coatings. One was [...] Read more.

Oil spill accidents have been a prevalent threat to the environment. To aid in clean-up efforts, a stainless-steel filter with a hydrophilic and oleophobic coating was fabricated for efficient and affordable oil/water separation. Two solutions were used to deposit the coatings. One was sourced from a titanium (IV) isopropoxide (TTIP) precursor dissolved into 1-butanol and the other through the mixing of titanium dioxide nanopowder with glacial acetic acid. The solutions were applied to 304 stainless-steel mesh filters of varying aperture sizes ranging from 30 microns to 240 microns. The coating was applied through a multiphase deposition method followed by sintering at 450 °C. The filter performance was evaluated by contact angle measurement and a filtration test using a mixture of motor oil and water, while the surface morphology and structure of the coatings were characterized by SEM-EDS and XRD. The mesh with smaller aperture size showed oil retention improvement of up to 99%. The TiO₂ nanopowder coating, with a 92% oil retention efficiency, outperformed the coating via the TTIP precursor. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Figure 1

13 pages, 3639 KiB

Open AccessArticle

Simulation Evaluation of a Novel Ice-Melting Sprinkling Technique for Blade

by Gang Lei, Guohao Li and Fang Feng

Coatings 2023, 13(10), 1752; https://doi.org/10.3390/coatings13101752 - 10 Oct 2023

Viewed by 738

Abstract

The blades of some airborne equipment are prone to icing under supercooled cloud conditions. In this paper, we propose an anti-deicing spray method to prevent blades from icing at low temperatures. Using computational fluid dynamics modeling and orthogonal experimental methods, we investigated the [...] Read more.

The blades of some airborne equipment are prone to icing under supercooled cloud conditions. In this paper, we propose an anti-deicing spray method to prevent blades from icing at low temperatures. Using computational fluid dynamics modeling and orthogonal experimental methods, we investigated the effects of the blade angle of attack, inlet wind speed, and nozzle mass flow rate on the thickness and coverage of the liquid layer of spray material and examined the use of deflectors in this study. We found the magnitude and change rule of the influence of the previously mentioned parameters on the liquid film thickness and coverage of sprayed material to be the nozzle mass flow rate is greater than the blade angle of attack and greater than the inlet wind speed. Under the optimal combination of conditions of α = 30°, u₀ = 6 m/s, and Q = 0.003 kg/s, the liquid film thickness was maximized, and the liquid film thickness was 0.037 mm; under the optimal combination of conditions of α = 60°, u₀ = 6 m/s, and Q = 0.003 kg/s, the liquid film coverage was maximized, and the liquid film coverage was 99.81%. The anti-deicer spraying method proposed herein for use on blades is effective when considered from a number of perspectives. It provides an innovative and feasible solution to the wind turbine blade freezing problem. However, the method must be explored and modified to maximize its chances of general application, and other factors must also be considered to fully optimize the sprinkler de-icing technique to improve the performance and reliability of blades. Full article

(This article belongs to the Special Issue Recent Developments on Functional Coatings for Industrial Applications, Volume II)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Recent Developments on Functional Coatings for Industrial Applications, Volume II

Share This Special Issue

Special Issue Editors

Special Issue Information

Related Special Issue

Published Papers (9 papers)

Editorial

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI