CFD Sensitivity Study of Stirling High Temperature Components Based on Heat Pipe Heat Transfer
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摘要: 热管-斯特林耦合结构是热管堆系统中热管传热管束与斯特林发电机的几何和传热接口,负责将热管传递过来的堆芯热量传递给斯特林发电机内部的氦气工质。本文采用计算流体动力学(CFD)方法对热管-斯特林耦合结构的传热过程进行了计算分析,研究了多种冷、热边界对有效传热量、总传热温差等特征参数以及孔道表面温度分布的影响规律。研究结果表明,氦气侧换热能力对传热过程有一定影响,提高对流换热系数或降低氦气温度有利于进一步提高有效传热量。相比之下,热管侧边界条件对传热过程的影响更大,有可能在耦合结构的起始位置造成很大的温度梯度,使总传热温差明显变大,进而影响热管传热安全。因此,需要增强热管向斯特林高温部件的传热能力,并将最大热流密度限制在150 kW/m2以下,以确保热管堆系统运行过程中的热工安全。
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关键词:
- 边界敏感性 /
- 计算流体动力学(CFD)计算 /
- 斯特林传热单元 /
- 热管堆
Abstract: The heat pipe-Stirling coupling structure refers to the geometric and heat transfer interface between heat pipe bundles and the Stirling generator in the heat-pipe nuclear reactor system, responsible for transferring core heat from the heat pipes to the helium working fluid inside the Stirling engine. This study employs the computational fluid dynamics (CFD) method to numerically analyze the heat transfer process in the heat pipe-Stirling coupling structure, investigating the influence of various cold and hot boundary conditions on characteristic parameters such as effective heat transfer capacity, total temperature difference, and temperature distribution on the channel surface. The results show that the heat transfer capacity of helium side has a certain influence on the heat transfer process, and increasing the convective heat transfer coefficient or decreasing the helium temperature is beneficial to further improve the effective heat transfer. In contrast, the boundary conditions on the heat pipe side have a greater influence on the heat transfer process, which may cause a large temperature gradient at the initial position of the coupling structure and obviously increase the total heat transfer temperature difference, thus affecting the heat transfer safety of the heat pipe. Therefore, it is necessary to improve the heat transfer capability from heat pipes to Stirling high-temperature components while limiting the maximum heat flux density below 150 kW/m² to ensure thermal safety during heat pipe reactor system operation. -
表 1 冷端边界的敏感性计算工况
Table 1. Sensitivity Calculation of Cold-side Boundary
工况 边界条件 孔道
壁温/℃氦气
温度/℃对流换热系数/
(W·m−2·K−1)1-0 等壁温边界 850 700 4000 1-1 等壁温边界 850 600 4000 1-2 等壁温边界 850 650 4000 1-3 等壁温边界 850 750 4000 1-4 等壁温边界 850 800 4000 2-1 等壁温边界 850 700 2000 2-2 等壁温边界 850 700 3000 2-3 等壁温边界 850 700 5000 2-4 等壁温边界 850 700 6000 表 2 多种冷端边界条件下的CFD计算结果
Table 2. CFD Simulation Results under Different Cold-side Boundaries
工况 传热功率与偏差 传热温差 总传热功率/kW 最大单孔传热功率/kW 最小单孔传热功率/kW 孔道传热功率偏差/% 总温差/℃ 固体导热温差/℃ 氦气换热温差/℃ 1-0 225.0 6.14 5.05 9.7 150 81.8 68.2 1-1 375.0 10.20 8.41 9.7 250 136.2 113.8 1-2 300.0 8.19 6.73 9.7 200 109.0 91.0 1-3 150.0 4.10 3.36 9.7 100 54.5 45.5 1-4 75.0 2.05 1.68 9.7 50 27.2 22.8 2-1 150.8 4.07 3.56 6.8 150 58.5 91.5 2-2 192.7 5.24 4.41 8.6 150 72.0 78.0 2-3 251.0 6.87 5.55 10.6 150 89.1 60.9 2-4 272.6 7.48 5.96 11.2 150 94.9 55.1 表 3 热端边界的敏感性计算工况
Table 3. Sensitivity Calculation of Hot-side Boundary
工况 边界条件 孔道
壁温/℃热流密度/
(kW·m−2)氦气
温度/℃对流换热系数/
(W·m−2·K−1)1-0 等壁温边界 850 700 4000 3-1 等壁温边界 750 700 4000 3-2 等壁温边界 800 700 4000 3-3 等壁温边界 900 700 4000 3-4 等壁温边界 950 700 4000 4-1 等热流边界 150 700 4000 4-2 等热流边界 200 700 4000 4-3 等热流边界 250 700 4000 4-4 等热流边界 300 700 4000 4-5 等热流边界 350 700 4000 表 4 多种热端边界条件下的CFD计算结果
Table 4. CFD Simulation Results under Different Hot-side Boundaries
工况 传热功率与偏差 传热温差 总传热功率/kW 最大单孔传热功率/kW 最小单孔传热功率/kW 孔道传热功率偏差/% 总温差/℃ 固体导热温差/℃ 氦气换热温差/℃ 1-0 225.0 6.14 5.05 9.7 150.0 81.8 68.2 3-1 75.0 2.05 1.68 9.7 50.0 27.2 22.8 3-2 150.0 4.10 3.36 9.7 100.0 54.5 45.5 3-3 300.0 8.19 6.73 9.7 200.0 109.0 91.0 3-4 375.0 10.20 8.41 9.7 250.0 136.2 113.8 4-1 91.5 2.48 1.99 10.5 114.7 86.9 27.8 4-2 122.1 3.30 2.66 10.5 152.9 115.9 37.0 4-3 152.6 4.13 3.32 10.5 191.2 144.9 46.3 4-4 183.1 4.95 3.99 10.5 229.4 173.8 55.6 4-5 213.6 5.78 4.65 10.5 267.6 202.8 64.8 -
[1] WALKER G, SENFT J R. Free Piston Stirling Engines[M]. Springer, Berlin, 1985, 128-144. [2] SLABY J G. Overview of NASA Lewis research center free-piston Stirling engine activities[C]//19th Intersociety Energy Conversion Engineering Conference. San Francisco: U. S. Department of Energy, 1984. [3] SLABY J G. Overview of free-piston Stirling SP-100 activities at the NASA Lewis research center[C]//3rd International Stirling Engine Conference. Rome: U. S. Department of Energy, 1986. [4] GIBSON M A, POSTON D I, MCCLURE P, et al. Kilopower reactor using Stirling technology (KRUSTY) nuclear ground test results and lessons learned: NASA/TM—2018-219941[R]. Cleveland: National Aeronautics and Space Administration, Glenn Research Center, 2018. [5] POSTON D I, MCCLURE P R, DIXON D D, et al. Experimental demonstration of a heat pipe–Stirling engine nuclear reactor[J]. Nuclear Technology, 2014, 188(3): 229-237. doi: 10.13182/NT13-71 [6] GIBSON M A, POSTON D I, MCCLURE P R, et al. Heat transport and power conversion of the Kilopower reactor test[J]. Nuclear Technology, 2020, 206(S1): 31-42. [7] 骆成栋,罗雨微,杨伟杰,等. 美国空间核动力斯特林电源系统技术发展分析[J]. 国际太空,2021(6): 44-48. doi: 10.3969/j.issn.1009-2366.2021.06.011 [8] 张蓉,闫春杰,罗新奎,等. 不同温比下自由活塞斯特林发电机的数值研究[J]. 低温工程,2024(5): 79-86. doi: 10.3969/j.issn.1000-6516.2024.05.010 [9] 李雪岭,李冰淇,刘洋,等. 月球碟式斯特林光热发电系统性能分析[J]. 工程热物理学报,2024, 45(12): 3603-3610. [10] 常德鹏,孙岩雷,王珏,等. 双作用斯特林热机内部气体微团运行机理数值研究[J]. 太阳能学报,2024, 45(6): 389-395. [11] 周远,罗二仓. 热声热机技术的研究进展[J]. 机械工程学报,2009, 45(3): 14-26. [12] 毕天骄,吴张华,余国瑶,等. 热声发动机核心单元热功转换性能的研究[J]. 工程热物理学报,2017, 38(12): 2542-2547. [13] 游尔胜,张廷,张友佳,等. 斯特林动力转换技术在微型核装置中的应用分析[J]. 科学技术创新,2023(9): 58-62. doi: 10.3969/j.issn.1673-1328.2023.09.016 [14] 游尔胜,张廷,幸奠川,等. 斯特林动力转换系统性能及应用技术研究[J]. 核动力工程,2024, 45(5): 269-276. [15] SCHREIBER J G. Summary of Stirling convertor testing at GRC[C]//4th International Energy Conversion Engineering Conference and Exhibit (IECEC). San Diego: AIAA, 2006. [16] BRIGGS M H, GENG S M, PEARSON J B, et al. Summary of test results from a 1 kWe-class free-piston Stirling power convertor integrated with a pumped NaK loop: NASA/TM—2010-216934[R]. Cleveland: National Aeronautics and Space Administration, Glenn Research Center, 2010. -