Biomass energy, as a reliable renewable energy source, has gained more and more attention. However, microstructure degradation and corrosion fatigue damage of heat pipes hinder its further application. In this paper, high temperature corrosion fatigue characteristics of 12Cr1MoV steel under a mixed alkali metal chloride salt environment and mixed sulfate salt environment were investigated. Fatigue tests with different total strain amplitudes were performed. Results show that the effect of total strain amplitude on the cyclic stress response of the alloy is approximately the same under three different deformation conditions. With the increase of the cyclic numbers, the alloyed steel mainly exhibited cyclic hardening during loading. The fatigue properties in air environment were the best, which is most obvious when the total strain amplitude is ±0.3%. The fatigue life of samples in mixed alkali metal salts is the shortest. Furthermore, the fatigue fracture morphology of the alloyed steel in different environments were also deeply analyzed. This experimental study attempts to provide a theoretical reference for solving the problem of rapid failure of heat pipes in biomass boilers, and to establish a scientific basis for the material selection and safety operation.

As a surface functional material, super-hydrophobic coating has great application potential in wind turbine blade anti-icing, self-cleaning and drag reduction. In this study, ZnO and SiO 2 multi-scale superhydrophobic coatings with mechanical flexibility were prepared by embedding modified ZnO and SiO 2 nanoparticles in PDMS. The prepared coating has a higher static water contact angle (CA is 153°) and a lower rolling angle (SA is 3.3°), showing excellent super-hydrophobicity. Because of its excellent superhydrophobic ability and micro-nano structure, the coating has good anti-icing ability. Under the conditions of −10 C and 60% relative humidity, the coating can delay the freezing time by 1511S, which is 10.7 times slower than the normal freezing time. More importantly, due to the mechanical properties provided by SiO 2 and the synergistic effect of micro-nano particles, the coating has excellent mechanical durability. After 10 wear tests, the contact angle of the coating is still as high as 141°and the rolling angle is 6.8°. This research provides a theoretical reference for the preparation of a mechanically stable coating with a simple preparation process, as well as a basic research on the anti-icing behavior of the coating.

Aiming at the problem of wind turbine blades' icing, a carbon nanotube composite photothermal coating with both active deicing and passive anti-icing properties was prepared by the spin-coating method. The results indicate that the lubricating coating doped with carbon nanotubes can effectively delay freezing time and reduce ice adhesion strength. The spin-coated 6-layer coating can achieve the best photothermal conversion performance and consume relatively few nanomaterials to maximize the capture of energy in near-infrared light. Under the irradiation of near-infrared light (808 nm), the surface temperature of the coating can reach 97.1°C, which has good photothermal conversion performance. The antifrosting ability of carbon nanotube nanocomposite photothermal coating is related to the content of lubricating oil, and the defrosting performance is related to the content of carbon nanotubes in the coating. Adopting the lubrication-photothermal synergistic deicing method can greatly shorten the deicing time, which is compared with only using photothermal deicing from 392 s to 51 s.

No abstract

No abstract