Optimization of heat removal modes for heat exchanger in molten salt single storage tank

doi:10.11949/j.issn.0438-1157.20180712

Abstract

Abstract:

Low cost heat charge and discharge can be realized by immersion arrangement of a helically coiled heat exchanger in molten salt single storage tank. Heat removal modes of the helically coiled heat exchanger will directly affect the heat discharge process of the storage system. Simulations were performed for two heat removal modes which include upper-lower path and lower-upper path. For different heat removal modes in the heat discharge process, the law of heat discharge performance of the molten salt single storage tank is given, and the change of flow field of molten salt side is analyzed. The results show that upper-lower path for the helically coiled heat exchanger can improve the transient out temperature, transient heat transfer rate and heat discharge efficiency. The research results provide a theoretical basis for the design of the molten salt single tank heat storage and discharge system.

Key words: immersed heat exchanger, heat removal mode, heat discharge process, molten salt single tank, convection, heat transfer, flow

摘要：

盘管释热换热器浸没式布置在熔盐单罐蓄热器内可实现低成本的蓄放热。盘管换热器取热方式会直接影响系统的释热性能。通过数值模拟研究了换热器取热方式对单罐蓄热系统释热性能规律的影响，同时分析了释热过程中熔盐侧流场变化。结果表明，换热器上进下出的取热方式能够提高盘管换热器的出口温度、单罐释热功率及释热效率，研究结果为熔盐单罐蓄放热系统设计提供了理论依据。

关键词: 浸没式换热器, 取热方式, 释热过程, 熔盐单罐, 对流, 传热, 流动

CLC Number:

Suli SHI, Yuanwei LU, Qiang YU, Yuting WU. Optimization of heat removal modes for heat exchanger in molten salt single storage tank[J]. CIESC Journal, 2019, 70(3): 857-864.

施素丽, 鹿院卫, 于强, 吴玉庭. 熔盐单罐释热过程换热器取热方式优选[J]. 化工学报, 2019, 70(3): 857-864.

Figures/Tables 10

Fig.1 Schematic diagram of model principle

Fig.2 Subdomains for molten salt domain

Fig.3 Detailed views of grids

Fig.4 Data comparison between numerical simulation and experiment

Fig.5 Comparison of transient outlet temperature under different heat removal mode

Fig.6 Comparison of transient heat transfer rate under different heat removal mode

Fig.7 Comparison of heat discharge efficiency under different heat removal mode

Fig.8 Molten salt temperature inside storage tank (V inlet = 25 m/s)

Fig.9 Temperature contours of single storage tank/K

Fig.10 Velocity of molten salt around heat exchanger

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