Study on the Effect of Inclination Angle on the Natural Convection of Molten Salt in Heat Pipe Cooled Molten Salt Reactor Core
-
摘要: 热管熔盐堆堆芯倾角对堆芯温度分布和局部热点具有重要影响。为获得堆芯在不同倾角下内部熔盐的自然对流换热特性、优化堆芯设计和提高系统安全性,对堆芯进行三维建模,通过Fluent软件进行数值模拟,对横置和竖置放置2种情况下堆芯内熔盐自然对流的温度场和流场进行了分析,同时讨论了堆芯倾角变化对堆芯温度场及局部热点的影响。研究结果表明:局部热点始终出现在堆芯上部,相对于竖置,横置时堆芯温度场及流场更加不稳定。当倾角在5°~10°范围内,局部热点温度最高,竖置时热点温度最低。模拟结果揭示了堆芯内熔盐的自然对流特性,并为热管熔盐堆热工方面的概念设计提供了一定参考。Abstract: The inclination angle of heat pipe-cooled molten salt reactor (MSR) core has an important influence on the core temperature distribution and local hot spots. In order to obtain the natural convection heat transfer characteristics of molten salt in the core at different inclination angles, optimize the core design and improve the system safety, the three-dimensional modeling of the core is carried out, and the temperature field and flow field of the natural convection of molten salt in the core are analyzed for both horizontal and vertical placement by numerical simulation with the software Fluent. At the same time, the influence of core inclination angle change on the core temperature field and local hot spots is discussed. The results show that the local hot spots always appear in the upper part of the core, and the temperature field and flow field of the core are more unstable when the core is placed horizontally than vertically. When the inclination angle is in the range of 5°-10°, the local hot spot temperature is the highest, and the hot spot temperature is the lowest when the core is vertical. The simulation results show the natural convection characteristics of molten salt in the core, and provide a reference for the thermal design of the heat pipe-cooled MSR.
-
Key words:
- Heat pipe-cooled MSR /
- Inclination angle /
- Natural convection /
- Heat transfer
-
表 1 热管熔盐堆堆芯参数表
Table 1. Main Parameters of Heat Pipe-cooled MSR Core
参数 数值 堆芯热功率/kW 30 堆芯高度/mm 620 堆芯直径/mm 350 热管数量/根 37 热管中心距/mm 48.73 热管直径/mm 32 热管长度/mm 620 表 2 熔盐的物性性质
Table 2. Physical Properties of Molten Salt
物性参数 数值 熔盐成分 72.5LiF-27.5UF4 熔点/K 858 密度/(kg·m−3) 6105−1.272Tsalt 比热容/(J·kg−1·K−1) 1000 动力粘度/(Pa·s) 0.07696·exp[(4976/Tsalt)/1000] 热导率/(W·m−1·K−1) 1.1 -
[1] WANG X, ZHANG Q, ZHUANG K, et al. Neutron physics of the liquid‐fuel heat‐pipe reactor concept with molten salt fuel—Static calculations[J]. International Journal of Energy Research, 2019, 43(14): 7852-7865. [2] LIU M H, ZHANG D L, WANG C L, et al. Experimental study on heat transfer performance between fluoride salt and heat pipes in the new conceptual passive residual heat removal system of molten salt reactor[J]. Nuclear Engineering and Design, 2018, 339: 215-224. doi: 10.1016/j.nucengdes.2018.09.015 [3] PETRUCCI M, FAGHRI A. Multiple evaporator and condenser loop thermosyphon system for passive cooling of liquid-fuel molten salt nuclear reactors[J]. Nuclear Engineering and Design, 2020, 370: 110936. doi: 10.1016/j.nucengdes.2020.110936 [4] 于世和,孙强,赵恒,等. 火星熔盐堆堆芯概念设计[J]. 核技术,2020, 43(5): 67-72. doi: 10.11889/j.0253-3219.2020.hjs.43.050603 [5] CUI D Y, DAI Y, CAI X Z, et al. Preconceptual nuclear design of a 50 kWth heat pipe cooled micro molten salt reactor (micro-MSR)[J]. Progress in Nuclear Energy, 2021, 134: 103670. doi: 10.1016/j.pnucene.2021.103670 [6] 胡光,崔德阳,卢林远,等. 1MWth火星表面热管熔盐堆堆芯初步中子学设计[J]. 核技术,2021, 44(12): 97-106. doi: 10.11889/j.0253-3219.2021.hjs.44.120603 [7] 余红星,马誉高,张卓华,等. 热管冷却反应堆的兴起和发展[J]. 核动力工程,2019, 40(4): 1-8. doi: 10.13832/j.jnpe.2019.04.0001 [8] 李华琪,江新标,陈立新,等. 空间堆热管输热能力分析[J]. 原子能科学技术,2015, 49(1): 89-95. doi: 10.7538/yzk.2015.49.01.0089 [9] TENG W F, WANG X Y, ZHU Y Z. Experimental investigations on start-up and thermal performance of sodium heat pipe under swing conditions[J]. International Journal of Heat and Mass Transfer, 2020, 152: 119505. doi: 10.1016/j.ijheatmasstransfer.2020.119505 [10] JANZ G J, GARDNER G L, KREBS U, et al. Molten salts: volume 4, part 1, fluorides and mixtures electrical conductance, density, viscosity, and surface tension data[J]. Journal of Physical and Chemical Reference Data, 1974, 3(1): 1-115. doi: 10.1063/1.3253134 [11] CHEN X W, ZOU Y, CHEN Z H, et al. Effect of core configuration on natural convection and heat transfer in heat pipe cooled micro-MSRs[J]. Nuclear Engineering and Design, 2022, 395: 111839. doi: 10.1016/j.nucengdes.2022.111839 [12] PEROVIĆ B D, KLIMENTA J L, TASIĆ D S, et al. Modeling the effect of the inclination angle on natural convection from a flat plate: the case of a photovoltaic module[J]. Thermal Science, 2017, 21(2): 925-938. doi: 10.2298/TSCI140821059P [13] NIAZI S, BENI M N. Numerical study of the effect of a nanofluid with nanoparticles of nonuniform size on natural convection in an inclined enclosure[J]. Nanoscience and Technology:An International Journal, 2017, 8(4): 261-308. doi: 10.1615/NanoSciTechnolIntJ.v8.i4.10 [14] LU S H, ZHU J Q, GAO D Y, et al. Lattice Boltzmann simulation for natural convection of supercritical CO2 in an inclined square cavity[J]. International Journal of Numerical Methods for Heat & Fluid Flow, 2020, 30(7): 3635-3652. doi: 10.1108/HFF-08-2019-0641 [15] ELBAKHSHAWANGY H F. Effect of tilting angle on natural convection heat transfer from a cylinder suspended in stagnant water[J]. Arab Journal of Nuclear Sciences and Applications, 2020, 53(2): 56-67. doi: 10.21608/ajnsa.2020.15243.1244 [16] ROY K, DAS B, DUTTA S. Natural convective heat transfer from an inclined isothermal fin array[C]// Advances in Mechanical Engineering. Singapore: Select Proceedings of ICRIDME 2018. Springer Singapore, 2020: 1055-1068. [17] ASHJAEE M, YOUSEFI T. Experimental study of free convection heat transfer from horizontal isothermal cylinders arranged in vertical and inclined arrays[J]. Heat Transfer Engineering, 2007, 28(5): 460-471. doi: 10.1080/01457630601165822 [18] 贾笃雨. 高温熔盐在圆管表面自然对流换热的数值研究[D]. 天津: 河北工业大学, 2016. [19] REYMOND O, MURRAY D B, O’DONOVAN T S. Natural convection heat transfer from two horizontal cylinders[J]. Experimental Thermal and Fluid Science, 2008, 32(8): 1702-1709. doi: 10.1016/j.expthermflusci.2008.06.005 [20] WANG C L, QIN H, ZHANG D L, et al. Numerical investigation of natural convection characteristics of a heat pipe-cooled passive residual heat removal system for molten salt reactors[J]. Nuclear Science and Techniques, 2020, 31(7): 87-95. doi: 10.1007/s41365-020-00780-z [21] YODER G L JR, HEATHERLY D W, WILLIAMS D F, et al. Liquid fluoride salt experimentation using a small natural circulation cell: ORNL/TM-2014/56[R]. Oak Ridge: Oak Ridge National Lab, 2014. [22] 杨世铭, 陶文铨. 传热学[M]. 第四版. 北京: 高等教育出版社, 2006: 267-269. [23] YODER G L JR. Examination of liquid fluoride salt heat transfer[C]//Proceedings of the ICAPP 2014. Charlotte, 2014: 6-9 [24] TSUBOUCHI T, MASUDA H. Heat transfer by natural convection from horizontal cylinders at low Rayleigh numbers[R]. Tohoku: Tohoku University, 1967, 19: 205-219 [25] CHURCHILL S W, CHU H H S. Correlating equations for laminar and turbulent free convection from a horizontal cylinder[J]. International Journal of Heat and Mass Transfer, 1975, 18(9): 1049-1053. doi: 10.1016/0017-9310(75)90222-7