Spiral fins play a significant role in enhancing heat transfer in phase-change energy storage devices. Four types of spiral fins with different compression ratios were used to analyze the effect of the number of fins on the solidification of phase change materials. First, the solidification process of the phase change material in the spiral fin energy storage tank with different compression ratios was numerically simulated, and the temperature distribution and change in the phase change interface in the four energy storage tanks with time were discussed. Second, the liquid phase fraction, average temperature, total heat release, solidification time, and average heat release rate were analyzed. The results indicate that the design of spiral fins with an appropriate compression ratio can effectively promote the solidification of phase-change materials in energy storage devices, reduce the phenomenon of vertical stratification at lower temperatures, and optimize the heat release performance of phase-change energy storage tanks. Compared with the standars energy storage tank, the average heat release rate of paraffin wax in the energy storage tank with a compression ratio of 3 increases from 86.7 J/s to 93.9 J/s, representing an increase of 8.7%. The complete solidification time is reduced by 6.6%. When the compression ratio is 5 and 7, the average heat release rate decreases to 84.7 J/s and 63.8 J/s, representing a decrease of 2.3% and 26.4%, respectively. The complete solidification time increases by 18% and 38.7%, respectively. For a constant volume of PCM, the energy storage tanks with 8, 10, and 12 fins completes the heat release as a whole, and the heat release effect of the energy storage tank with 14 fins is not as good as that of the tank with 6 fins, indicating that more spiral turns are not always better. As the compression ratio and number of fins increase, the solidification rate initially increases and then decreases, while the time required for complete solidification decreases before increasing again.
Key words
phase change materials /
heat transfer performance /
compression ratio /
spiral fins /
number of fins
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