Nitrate molten salt-based nanofluid flow and heat transfer characteristics in twisted tube

doi:10.19799/j.cnki.2095-4239.2022.0356

Abstract

Abstract:

In concentrating solar power plant, molten salt is widely used for heat transfer and energy storage medium. It is found that the thermophysical properties of molten salt can be improved by adding nanoparticles to molten salt. In this paper, numerical simulation was used to analyze the flow and heat transfer characteristics of molten salt nanofluids in twisted tubes with different structures. The results show that the convective heat transfer coefficient and pressure drop of molten salt nanofluids in twisted tubes increase with the increase in the ratio of the long axis to short axis, and decrease with the increasing of the pitch. When Re = 10000—35000, the convective heat transfer coefficient of molten salt nanofluids in twisted tubes is 34.6% higher than that in smooth tube, and the maximum pressure drop is 141.3%. The empirical correlations of the nusselt number and resistance coefficient of molten salt nanofluids in twisted tubes are fitted. Through the comprehensive performance and field synergy analysis, it is found that when Re = 30000, the ratio of the long and short axis a/b = 2, and the pitch S = 300 mm. The maximum enhanced heat transfer factor is 1.16, and the synergy angle at the top of the long axis of the twisted tube is the smallest.

Key words: molten salt based nanofluids, twisted tube, heat transfer, number simulation

CLC Number:

TK 02

Cancan ZHANG, Songtao HAN, Yuting WU, Yuanwei LU, Junnan NIU. Nitrate molten salt-based nanofluid flow and heat transfer characteristics in twisted tube[J]. Energy Storage Science and Technology, 2022, 11(11): 3641-3648.

Figures/Tables 13

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