Numerical study on heat transfer characteristics of molten salt in annular channel with wire coil

Abstract In order to develop a heat transfer enhancement technique for molten salt heat exchanger, Fluent simulation is carried out to investigate the molten salt flow and heat transfer performances in annular channels with wire coil. Two experimental set-ups were built to measure the temperature distribution of the test section, and the maximum relative deviation between the simulated temperature and experimental one is 3.27%. The effects of the wire width and helical pitch on heat transfer and flow characteristics, and the mechanism of heat transfer enhancement in wire coil inserted annular channels are discussed in the light of numerical results. It is found that adding coiled wire inserts in an annular channel can enhance the heat transfer performance by up to eight times as compared to a smooth annular channel, at a cost of higher flow resistance. The thermal performance factor is evaluated, which is greater than 3.7 at a constant pumping power. Finally, the heat transfer and friction factor correlations for annular channels with wire coil are proposed.