Analytical method on heat conduction performance of anisotropic pin fins
-
摘要:
构建了描述各向异性材料针形翅片导热问题的数学模型,通过无量纲化分析获得了影响翅片传热过程的无量纲准则数。采用分离变量、泰勒展开、积分平均等方法对微分方程进行解析求解,获得了翅片效率、翅片表面总传热速率等参数的解析计算方法,并采用CFD数值结果验证计算精度。根据所提解析方法,分析了各向异性材料导热主轴的方向对翅片传热性能的影响规律。结果表明:在径向毕渥数取0.05~10、轴向毕渥数取0.005~10、交叉项毕渥数0.2~10、翅片长径比取2~20范围内,本研究所得公式的翅片效率计算偏差与数值方法相比不超过1.06%;由于温度分布具有周向对称性,因此当导热主轴在
rO φ 和φ Oz 平面偏转时使主导热系数较大的导热主轴沿r 向和z 向有利于提升翅片的传热能力;当导热主轴在rOz 平面偏转时,在给定边界条件、材料物性和翅片长径比的条件下,可以计算得到最佳的主轴偏转角度使翅片的传热能力最强,与α =0相比,传热速率的最佳强化效果可达2.97倍,为各向异性针形翅片的工程设计提供理论支撑。Abstract:A mathematical model was constructed to describe the heat conduction problem of anisotropic pin fins. Through dimensionless analyses, the dimensionless criterion numbers were obtained, which affected the heat transfer process of the fins. Variable separation method, Taylor expansion, and integral averaging were applied to solve the differential equation. Analytical correlations for fin efficiency and heat transfer rate were derived and numerically verified. Based on the proposed analytical solutions, the influence of the direction of the heat conductivity principal axis on anisotropic pin fins was analyzed. The results showed that within the range of radial
Bi was 0.05—10, axialBi was 0.005—10, crossBi was 0.2—10, and length to diameter ratio of fin was 2—20, the relative error of fin efficiency from the proposed correlation was less than 1.06% compared with the numerical results. Due to the circumferential symmetry of the temperature field, when the heat conductivity principal axis was deflected in therO φ andφ Oz planes, it was beneficial to enhance the fins’ heat transfer performance by making the axis, which had a higher principal heat conductivity coefficient along ther andz directions. However, when the axis was deflected in therOz plane, the optimal deflection angle can be calculated to maximize the heat transfer performance of the fins under given boundary conditions, material properties, and length to diameter ratio. And the maximum heat transfer rate was 2.97 times that ofα =0. The results provide a theoretical support for the design of anisotropic pin fins in application.-
Key words:
- anisotropic materials /
- pin fin /
- heat conduction /
- analytical solution /
- fin efficiency
-
表 1 各向异性针形翅片的无量纲参数
Table 1. Dimensionless numbers of anisotropic pin fins
参数 定义 无量纲过余温度 $\bar \theta $ $\dfrac{{T - {T_{\text{f}}}}}{{{T_{\text{w}}} - {T_{\text{f}}}}}$ 无量纲r坐标 $\bar r$ r/R ${\lambda _{rr}}$对应的毕渥数 Birr hR/λrr ${\lambda _{zz}}$对应的毕渥数 Bizz hR/λzz 无量纲z坐标 $\bar {\textit{z}}$ z/H 翅片长径比 βr H/R ${\lambda _{rz}}$对应的毕渥数 Birz hR/λrz 表 2 数值验证工况
Table 2. Operating conditions for numerical validation
工况 Birr Bizz Birz βr 1 0.05~10 0.005 ∞ 10 2 0.05 0.005~10 ∞ 10 3 0.05 0.005 0.02~10 10 4 0.05 0.005 ∞ 2~20 -
[1] 杜昆, 陈麒好, 孟宪龙, 等. 陶瓷基复合材料在航空发动机热端部件应用及热分析研究进展[J]. 推进技术, 2022, 43(2): 210380. DU Kun, CHEN Qihao, MENG Xianlong, et al. Advancement in application and thermal analysis of ceramic matrix composites in aeroengine hot components[J]. Journal of Propulsion Technology, 2022, 43(2): 210380. (in ChineseDU Kun, CHEN Qihao, MENG Xianlong, et al. Advancement in application and thermal analysis of ceramic matrix composites in aeroengine hot components[J]. Journal of Propulsion Technology, 2022, 43(2): 210380. (in Chinese) [2] BEHRENS E. Thermal conductivities of composite materials[J]. Journal of Composite Materials, 1968, 2(1): 2-17. doi: 10.1177/002199836800200101 [3] 周洲, 刘闯, 朱学忠, 等. 航空第二动力系统技术综述[J]. 航空动力学报, 2024, 39(8): 20220561. ZHOU Zhou, LIU Chuang, ZHU Xuezhong, et al. Review on aircraft secondary power system[J]. Journal of Aerospace Power, 2024, 39(8): 20220561. (in ChineseZHOU Zhou, LIU Chuang, ZHU Xuezhong, et al. Review on aircraft secondary power system[J]. Journal of Aerospace Power, 2024, 39(8): 20220561. (in Chinese) [4] 江华, 毛军逵, 屠泽灿, 等. 基于微结构识别的单向复合材料导热系数预估[J]. 航空动力学报, 2016, 31(11): 2641-2651. JIANG Hua, MAO Junkui, TU Zecan, et al. Thermal conductivity prediction of unidirectional composites based on microstructure identification[J]. Journal of Aerospace Power, 2016, 31(11): 2641-2651. (in ChineseJIANG Hua, MAO Junkui, TU Zecan, et al. Thermal conductivity prediction of unidirectional composites based on microstructure identification[J]. Journal of Aerospace Power, 2016, 31(11): 2641-2651. (in Chinese) [5] 李典森, 卢子兴, 刘振国, 等. 三维五向编织复合材料导热性能的有限元分析[J]. 航空动力学报, 2008, 23(8): 1455-1460. LI Diansen, LU Zixing, LIU Zhenguo, et al. Finite element analysis of thermal conductivity of three dimensional and five directional braided composites[J]. Journal of Aerospace Power, 2008, 23(8): 1455-1460. (in ChineseLI Diansen, LU Zixing, LIU Zhenguo, et al. Finite element analysis of thermal conductivity of three dimensional and five directional braided composites[J]. Journal of Aerospace Power, 2008, 23(8): 1455-1460. (in Chinese) [6] 陆思达, 高希光, 宋迎东. 基于有限元法的平纹编织C/SiC复合材料等效导热系数预测方法[J]. 航空动力学报, 2014, 29(7): 1574-1582. LU Sida, GAO Xiguang, SONG Yingdong. Prediction method on equivalent thermal conductivity coefficient of plain braided C/SiC composites material based on finite element method[J]. Journal of Aerospace Power, 2014, 29(7): 1574-1582. (in ChineseLU Sida, GAO Xiguang, SONG Yingdong. Prediction method on equivalent thermal conductivity coefficient of plain braided C/SiC composites material based on finite element method[J]. Journal of Aerospace Power, 2014, 29(7): 1574-1582. (in Chinese) [7] ASLIB I, HAMZA H, HANCHI N, et al. Numerical study of transient and steady-state anisotropic cylindrical pin fin thermal behavior[J]. Journal of Thermal Science and Engineering Applications, 2019, 11(3): 031007. doi: 10.1115/1.4042056 [8] AKULA R, BALAJI C. Thermal management of 18650 Li-ion battery using novel fins-PCM-EG composite heat sinks[J]. Applied Energy, 2022, 316: 119048. doi: 10.1016/j.apenergy.2022.119048 [9] 侯亚东, 单勇, 李江宁, 等. 各向异性复合材料平板气膜冷却特性实验和数值研究[J]. 航空动力学报, 2017, 32(10): 2384-2393. HOU Yadong, SHAN Yong, LI Jiangning, et al. Experimental and numerical studies on the film cooling characteristics of anisotropic composite plates[J]. Journal of Aerospace Power, 2017, 32(10): 2384-2393. (in ChineseHOU Yadong, SHAN Yong, LI Jiangning, et al. Experimental and numerical studies on the film cooling characteristics of anisotropic composite plates[J]. Journal of Aerospace Power, 2017, 32(10): 2384-2393. (in Chinese) [10] 屠泽灿, 毛军逵, 徐瑞, 等. 各向异性陶瓷基复合材料涡轮叶片概率性热分析方法[J]. 航空动力学报, 2017, 32(10): 2427-2437. TU Zecan, MAO Junkui, XU Rui, et al. Probabilistic thermal analysis of ceramic matrix composite turbine vane with anisotropic thermal conductivity[J]. Journal of Aerospace Power, 2017, 32(10): 2427-2437. (in ChineseTU Zecan, MAO Junkui, XU Rui, et al. Probabilistic thermal analysis of ceramic matrix composite turbine vane with anisotropic thermal conductivity[J]. Journal of Aerospace Power, 2017, 32(10): 2427-2437. (in Chinese) [11] 于国强, 隋正卿, 陈正扬, 等. 类椭圆形 CMC 火焰筒多斜孔冷却性能数值分析[J]. 航空动力学报, 2025, 40(1): 20230084. YU Guoqiang, SUI Zhengqing, CHEN Zhengyang, et al. Numerical analysis on cooling performance of quasi-elliptic multi inclined holes in CMC combustion liner[J]. Journal of Aerospace Power, 2025, 40(1): 20230084. (in ChineseYU Guoqiang, SUI Zhengqing, CHEN Zhengyang, et al. Numerical analysis on cooling performance of quasi-elliptic multi inclined holes in CMC combustion liner[J]. Journal of Aerospace Power, 2025, 40(1): 20230084. (in Chinese) [12] POWERS J M. On the necessity of positive semi-definite conductivity and Onsager reciprocity in modeling heat conduction in anisotropic media[J]. Journal of Heat Transfer, 2004, 126(5): 670-675. doi: 10.1115/1.1798913 [13] LUNA-ABAD J P, ALHAMA F. Design and optimization of composite rectangular fins using the relative inverse thermal admittance[J]. Journal of Heat Transfer, 2013, 135(8): 084504. doi: 10.1115/1.4024016 [14] ZUBAIR S M, ARIF A F M, SHARQAWY M H. Thermal analysis and optimization of orthotropic pin fins: a closed-form analytical solution[J]. Journal of Heat Transfer, 2010, 132(3): 031301. doi: 10.1115/1.4000059 [15] BAHADUR R, BAR-COHEN A. Orthotropic thermal conductivity effect on cylindrical pin fin heat transfer[J]. International Journal of Heat and Mass Transfer, 2007, 50(5/6): 1155-1162. [16] HSIEH M H, MA C C. Analytical investigations for heat conduction problems in anisotropic thin-layer media with embedded heat sources[J]. International Journal of Heat and Mass Transfer, 2002, 45(20): 4117-4132. doi: 10.1016/S0017-9310(02)00136-9 [17] CHANG Y P, TSOU R C H. Heat conduction in an anisotropic medium homogeneous in cylindrical regions—steady state[J]. Journal of Heat Transfer, 1977, 99(1): 132-134. doi: 10.1115/1.3450636 [18] NOROUZI M, RAHMANI H, BIRJANDI A K, et al. A general exact analytical solution for anisotropic non-axisymmetric heat conduction in composite cylindrical shells[J]. International Journal of Heat and Mass Transfer, 2016, 93: 41-56. doi: 10.1016/j.ijheatmasstransfer.2015.09.072 [19] KAYHANI M H, NOROUZI M, AMIRI DELOUEI A. A general analytical solution for heat conduction in cylindrical multilayer composite laminates[J]. International Journal of Thermal Sciences, 2012, 52: 73-82. doi: 10.1016/j.ijthermalsci.2011.09.002 [20] HILL R. Elastic properties of reinforced solids: some theoretical principles[J]. Journal of the Mechanics and Physics of Solids, 1963, 11(5): 357-372. doi: 10.1016/0022-5096(63)90036-X -

下载: