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Coal spontaneous combustion (CSC) is one of the main disasters in the process of coal mining. In this paper, the important role of high-latent heat phase change material CH3COONa·3H2O (SAT) in controlling CSC was studied and compared with common inhibitors (NaCl, CaCl2, ascorbic acid (VC)). The thermal performance characteristics of SAT were revealed by the C80 micromanometer, and the effects of different inhibitors on the thermal behavior of Shengli lignite were analyzed and compared. Furthermore, the gas–solid coaxial fixed bed measurement system was used in conjunction with the Pfeiffer online mass spectrometer, to design the natural temperature rise experiment of coal after the heating interruption in the same programmed temperature rise interval, investigating the effects of different inhibitors on the temperature and gas production in the process of coal oxidation. The results show that the heat absorption effect of SAT is more significant than common inhibitors, which not only improves the heat absorption rate of the samples but also increases the total heat absorption of the sample by 236.6 J·g−1 compared with the raw coal. In the programmed temperature rise experiment, the maximum temperature point of the SAT-inhibited coal sample is reduced by 15.5% compared with raw coal, the time to reach the maximum temperature point is delayed by 20.5%, and the SAT inhibitor effectively inhibits the production of CO and CO2 gases. The method described in this paper provides a new idea for the prevention and control of CSC. [ABSTRACT FROM AUTHOR]

This paper proposes a new correlation to evaluate the heat transfer coefficient between a vertical wall containing a phase change material (PCM) and air in a square enclosure. This correlation was determined in order to simulate the transient process during PCM discharge and its effect on the heat transfer inside the cavity without using complex CFD models. A 2D CFD model based on the resolution of Navier–Stokes and energy equations inside the air and the PCM was previously validated. It was used to generate numerical data in order to build the proposed heat transfer correlation. The new correlation is Nu = 0.186 · Ra 0.28 θ 0.271 Ste 0.022 valid for: 10 5 ≤ Ra ≤ 4.310 7 , 0.05 ≤ θ ≤ 1 and 0.05 ≤ ste ≤ 0.6 . The accuracy of the proposed correlation versus the correlations established without phase change is analysed through a simplified model considering only the PCM layer and replacing the air cavity by a flux condition with an appropriate heat transfer coefficient. The relative error being lower than 1%, the new correlation shows a better agreement with the CFD results than existing correlations. [ABSTRACT FROM AUTHOR]

The low thermal conductivity and liquid-phase leakage of phase change materials seriously hinder their large-scale applications. Porous materials have been identified as an effective way to address the leakage and provide a thermally conductive network. Therefore, we designed an expanded graphite-based multifunctional composite phase change thermal storage materials for personal thermal management and antimicrobial in medical protection. Expanded graphite (EG) was used as the matrix, silver nanowires (Ag NWs) as the functional enhancement materials, and n-octadecane (OD) as the thermal storage materials. OD and Ag NWs were adsorbed in the porous structure of EG by vacuum-assisted impregnation. Finally, EG/Ag NWs/OD were combined with non-woven fabrics (N) by one-step hot pressing method to obtain EG/Ag NWs/OD-N composite with excellent comprehensive performance. With the mass ratio of EG to Ag NWs of 13:7, EG/Ag NWs/OD-N exhibited a thermal conductivity of 2.0130 W m−1 K−1, which was improved by 1070.3% compared with pure OD. EG/Ag NWs/OD-N has a melting enthalpy of 137.85 J·g−1 and a crystallization enthalpy of 128.97 J·g−1. In addition, EG/Ag NWs/OD-N display great antibacterial properties, thermal cycling stability, shape stability, and cycling persistence and showed excellent temperature control in protective clothing applications, offering great potential for large-scale applications. [ABSTRACT FROM AUTHOR]