Dai Tao,Wu Zhanwu,Wang Zihan,Cui Sheng,Wu Xiaodong,Zhu Xiaofei
Fiber-reinforced aerogels with excellent properties such as low density and low thermal conductivity are potential thermal insulation materials. The slurry method and the embedding sintering method were used to fabricate MoSi 2 -aluminoborosilicate glass coatings on the surface of a carbon fiber-reinforced C-Al 2 O 3 aerogel composite under a low-oxygen atmosphere. The microstructure and phase composition of the coatings with different MoSi 2 contents before and after static oxidation were investigated. The resulting composite exhibited excellent radiating properties and outstanding oxidation resistance. The total emissivity of the as-prepared coatings was above 0.8185 in the wavelength range of 300–2500 nm. The sample with 40 wt% MoSi 2 in the outer coating had superior thermal endurance with a weight loss of only 0.54% after isothermal oxidation at 1200 °C for 180 min. This can be attributed to the optimum viscosity of the binder, which would relieve thermal stress defects and block oxygen diffusion. To further evaluate the thermal protection performance of the coatings, the heat transfer characteristics were simulated using the Fluent software package.
Graphical abstract
Sebastiano Tomassetti,Alessia Aquilanti,Pio Francesco Muciaccia,Gianluca Coccia,Christoph Mankel,Eduardus A.B. Koenders,Giovanni Di Nicola
The increasing use of renewable energy sources has highlighted the importance of energy storages, and in particular of latent heat thermal energy storages (LHTESs). Among the phase change materials (PCMs) that can be used in such systems, sugar alcohols (SAs) are considered potential substances that may lead to interesting applications in the LHTES sector. In this work, a detailed literature review analysis of six SAs (xylitol, sorbitol, erythritol, mannitol, inositol, dulcitol), their thermophysical properties, their thermal stability and their main LHTES applications is presented for the first time. The thermophysical properties under discussion include melting and crystallization temperatures , latent heats of melting and crystallization, specific heat, thermal conductivity , density and dynamic viscosity . Thermal stability was evaluated by taking into account studies of thermal endurance, degradation temperature and cycling stability. Differential scanning calorimetry (DSC), T -history, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were considered as measurement techniques. Applications include the use of SAs in solar collectors and cookers, heat exchangers , porous materials, absorption cooling systems, mobilized thermal energy storages (M-TESs). New measurements of phase transition properties and degradation temperature for the studied SAs were also carried out by the authors of the present study. A good agreement between the proposed data and the literature values was found. The analysis reveals that some SAs may be considered suitable for low-to-medium temperature LHTES applications, provided that their drawbacks are adequately evaluated and addressed. To this purpose, the study also highlights the most critical aspects that should be considered when developing both fundamental research and engineering applications related to SAs.
危险品化学品经营许可证（带存储）