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Graphical abstract Highlights • A novel method for determining thermophysical properties of PCM is proposed. • Multiple properties can be obtained simultaneously in one test. • The measured results agree well with the data reported in the literature. • The method is simple, low cost and has high measurement speed. Abstract In this paper, a novel method for determining the main thermophysical properties of phase change materials (PCM) is proposed, which can be called as “T-melting CHF” method. The melting point, fusion latent heat, thermal conductivity, and specific heat capacity in both solid and liquid phase of PCM, can all be obtained simultaneously by only one test. The theoretical fundamentals lying behind are introduced, the measurement apparatus and measurement principles are presented, and corresponding restrictive conditions for high accuracy measurement are provided. Theoretically, the thermophysical properties can be accurately measured by the proposed method if the test module can be perfectly insulated. However, heat loss inevitably exists in practical measurement, it will significantly influence the measuring accuracy, hence a correction method is proposed to improve this situation. A typical low melting point metal (gallium) and a typical organic PCM (n-eicosane) were tested to verify the feasibility and accuracy of the method. The experimental results agree well with the reference data reported in the literature. Compared with conventional measurement techniques, the method proposed here has advantages such as simple structure, low cost and high measurement speed; more importantly, it is able to measure multiple properties simultaneously. [ABSTRACT FROM AUTHOR]

A double distribution function lattice Boltzmann method (LBM) with multirelaxation time is implemented to simulate the Rayleigh-Benard convection melting of a typical low-melting-point metal in a rectangular cavity. Typical cases frequently encountered in practice with constant heat flux/constant temperature boundary conditions are parametrically investigated, with corresponding dimensionless results outlined; the influence of inclination angle of the cavity is also clarified. The computational speed of the current LBM would reach about 40 times faster than that of conventional finite volume method as performed by commercial software Fluent. The obtained results would be valuable for guiding practical thermal design. [ABSTRACT FROM AUTHOR]

In this paper, low melting point metal (LMPM), eutectic alloy Bi 31.6 In 48.8 Sn 19.6 ( E -BiInSn), was adopted as phase change material for potential thermal management applications. First, E -BiInSn was prepared and its main thermophysical properties were characterized. Then, transient thermal performances of E -BiInSn based heat sinks with internal crossed fins were tested, in comparison with that of organic PCM (octadecanol) which has close melting point. Three types of heat sink structures which have different number of internal fins were studied. Three heating conditions were applied, namely 80 W (2.2 W/cm 2 ), 200 W (5.6 W/cm 2 ) and 320 W (8.9 W/cm 2 ). For all of the cases, E -BiInSn exhibited much superior thermal performance than that of octadecanol. Furthermore, cyclic test of the E -BiInSn heat sink was carried out, which showed good repeatability and stability, and without supercooling. Finally, a simplified 3D conjugate numerical model was developed to simulate the melting process of LMPM heat sink, which showed good agreement with the experimental results. This simplified model would be much useful in practical thermal design and optimization of LMPM heat sink, for that it would significantly save the computational time consumption. [ABSTRACT FROM AUTHOR]

Low melting point metals (LMPMs) are a new kind of phase change materials (PCMs) which exhibit excellent heat extraction capability due to their high thermal conductivity. Such a characteristic renders it distinctive melting mode which hardly exists in conventional paraffin PCMs. In this paper, comprehensive numerical investigation is carried out to reveal the melting process of LMPMs. First, comparative simulations of typical paraffin eicosane and typical LMPM gallium is conducted. Then, dimensionless analysis is performed based on a series of parametric studies and corresponding dimensionless correlations are given under both constant wall temperature condition and constant heat flux condition. Further, the critical dimensionless values within which the correlations are applicable are suggested. Finally, a preliminary exploration is performed to illustrate the influence of natural convection under relatively high Ra number condition. This study can serve as a valuable reference for future practical thermal design of LMPMs based thermal management systems and thermal energy storage systems. [ABSTRACT FROM AUTHOR]

• A novel integrated cooling modality was introduced and investigated. • The calculation model of fluid-solid heat transfer process coped with phase change in the packed bed was established. • The thermal management ability of composite heat sink under typical conditions has been revealed. • The influences of different stacking patterns and operating parameters on the heat transfer enhancement in the packed bed were analyzed. This paper is dedicated to investigate the integrated cooling modality that the spherical low melting point metal (LMPM) macrocapsules were introduced and filled as phase change material (PCM) into a convective cooling heat sink. The fluid-solid heat transfer process coupled with phase change in the packed bed was numerically calculated based on the local thermal non-equilibrium theory and the effective specific heat capacity model which were validated in advance by conceptual experiments. The thermal management ability of composite heat sink packed with spherical LMPM-PCM macrocapsules under typical operating conditions has been revealed. In addition, the influences of different stacking patterns of LMPM particles, particle diameter and inlet velocity on the heat transfer enhancement in the packed bed were comprehensively investigated, respectively. It is found that compared with convective cooling heat sink alone, the composite heat sink filled with LMPM-PCM macrocapsules presents excellent thermal management performance. The temperature increment of heat source in the pulse heat load is reduced by 73.4%, which fully demonstrates the advantages of filling spherical particles. Besides, the Orthoclinal Stacking method achieves the largest volumetric heat transfer coefficient among different stacking patterns of equal-diameter spherical LMPM-PCM macrocapsules. What is more, the plateau duration of the solidification is gradually shortened with the decreasing diameter of the spherical LMPM-PCM macrocapsules and the increasing inlet velocity, which is advantageous for the system to quickly rehabilitate to normal operating temperatures during the de-pulse stage. Overall, this novel integrated cooling modality is proven to be a powerful and practical way to sustain extreme thermal management challenge. [ABSTRACT FROM AUTHOR]