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| 陶瓷基复合材料端壁气膜冷却特性实验数值研究 |
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杜昆1,2,3,4，陈麒好1,3,4，孟宪龙1,2,3，李华容1,3,4，仝麒琬1，王力泉1，梁庭睿1，刘存良1,3,4
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1.西北工业大学 动力与能源学院，陕西 西安 710072;2.西北工业大学 太仓长三角研究院，江苏 太仓 215400;3.西北工业大学 陕西省航空动力系统热科学重点实验室，陕西 西安 710129;4.西北工业大学 西北工业大学-喀山国立技术大学先进航空发动机热结构国际联合实验室，陕西 西安 710129
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| 摘要: |
| 为了解决陶瓷基复合材料（CMC）各向异性导热特点而带来的温度场分布变化问题，基于热固耦合数值模拟手段并采用等效导热系数法将CMC端壁导热系数等效为X，Y，Z三个方向的宏观等效导热系数，研究了主传热方向与次传热方向导热系数比（R），主传热方向与主流方向夹角（γ）与端壁冷效分布之间的关系。当端壁导热系数呈现各项异性特征时，端壁表面冷却带朝着主传热方向发生扭曲，R越大扭曲现象越明显。γ=0°时展向平均冷效峰值相比γ=90°要低15%～16%，而下游中心线冷却效率峰值则要高出11.1%～26.2%。对于无气膜覆盖的冷气出口上游区域，冷却带对主传热方向以及导热系数比的变化更为敏感。采用交错多排圆柱孔端壁结构进行了实验，对比了高温合金和CMC材料的综合冷效分布情况。在吹风比M=3～5情况下，CMC端壁的整体综合冷却效率比高温合金端壁低4.32%～5.10%，这主要是厚度方向导热系数的不同导致的。实验结果与理论模化公式结果符合良好，验证了模化公式的准确性。 |
| 关键词: 陶瓷基复合材料 各向异性导热系数 前倾扇形孔 多排孔端壁 综合冷却效率 热固耦合 |
| DOI：10.13675/j.cnki.tjjs.210440 |
| 分类号:V231.1 |
| 基金项目:国家自然科学基金（52006178）；国家科技重大专项基金（Y2019-VIII-0007-0168）；中央高校基本科研业务费专项资金（3102018zy019；3102020OMS701）。 |
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| Numerical and Experimental Study of Ceramic Matrix Composite on Endwall Film Cooling Performance |
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DU Kun1,2,3,4, CHEN Qi-hao1,3,4, MENG Xian-long1,2,3, LI Hua-rong1,3,4, TONG Qi-wan1, WANG Li-quan1, LIANG Ting-rui1, LIU Cun-liang1,3,4
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1.School of Power and Energy，Northwestern Polytechnical University，Xi’an 710072，China;2.Yangtze River Delta Research Institute，Northwestern Polytechnical University，Taicang 215400，China;3.Shaanxi Key Laboratory of Aeronautical Power System Thermal Science，Northwestern Polytechnical University， Xi’an 710129，China;4.NPU-KAI International Joint Laboratory of Advanced Aero-Engine Thermal Structure， Northwestern Polytechnical University，Xi’an 710129，China
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| Abstract: |
| In order to solve the problem of temperature distribution caused by anisotropic thermal conductivities of ceramic matrix composites （CMC）， the thermal conductivity of CMC endwall is set along X， Y and Z directions using the equivalent macroscopic thermal conductivity method based on the conjugate heat transfer simulation in this paper. The influence of thermal conductivity ratio （R） which refers to the ratio of main thermal conduction and the secondary thermal conduction and the angle （γ） between two thermal conduction directions on the endwall overall cooling efficiency distribution was studied. The cooling stripe twists towards the main heat transfer direction when the thermal conductivity of the endwall presents anisotropy characteristics. And this distortion became more obvious with the increasing of R. The maximum laterally averaged cooling effectiveness when γ=0° is 15%~16% lower than that of γ=90°， while the maximum downstream centerline overall cooling effectiveness is 11.1%~26.2% higher. The cooling stripe appears to be more sensitive to the main heat transfer direction and the thermal conductivity ratio at the upstream region without film coverage. Experiments were implemented with multi rows staggered cylindrical film hole endwall structure to compare the overall cooling effectiveness of superalloy and CMC. When the blowing ratio M varies within 3 to 5， the overall cooling effectiveness of CMC endwall is 4.32%~5.10% lower than the superalloy endwall. This gap is mainly caused by thermal conductivity difference along thickness direction. The experimental results agree well with the theoretical analogy principles， therefore which verifies the accuracy of the analogy principles. |
| Key words: Ceramic matrix composites Anisotropic thermal conductivity Laidback fan-shaped hole Multi rows film hole endwall Overall cooling effectiveness Conjugate heat transfer |
