C/SiC复合材料的人工孔发汗冷却性能分析及优化研究  

Analysis and optimization of transpiration cooling performance for C/SiC composites with artificial holes

作　　者：俞逸斯 李明佳 杜燊 戴嘉鹏 徐航[2] YU Yisi;LI Mingjia;DU Shen;DAI Jiapeng;XU Hang(Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education,School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China;School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]西安交通大学能源与动力工程学院,热流科学与工程教育部重点实验室,西安710049 [2]北京理工大学机械工程学院,北京100081

出　　处：《空气动力学学报》2024年第6期88-95,I0002,共9页Acta Aerodynamica Sinica

摘　　要：C/SiC复合材料在热防护领域中应用广泛,但受制备工艺、成本等方面的限制,具有低孔隙率、小孔径的特征,在发汗冷却过程中这些微小孔隙难以支撑足够的冷却剂供应量且易发生堵塞,限制了冷却的进行。针对此问题,本文研究通过增加人工孔来改善C/SiC复合材料发汗冷却性能的可行性。建立了人工孔表征单元结构及等效模型,获得了打孔后复合材料内冷却工质的流量比及等效渗透率的变化情况,探究了打孔方式与工质流量对复合材料等效体换热系数的影响规律,并拟合了打孔后复合材料等效体换热系数经验公式。结果表明:渗透特性方面,冷却工质的主要流量分布于人工孔中;对于渗透率为1×10^(-16) m^(2)的低渗透率材料,打孔后复合材料自身工艺孔中的流量占比小于0.1%,其中的工质流动可忽略;在换热特性方面,可通过调节打孔方式改善复合材料的换热性能,相同渗透率下调节打孔方式可使体换热系数提升154%。Constrained by the constraints of the C/SiC composites fabrication process,as well as cost and other factors,these composites exhibit attributes of low porosity and small pore sizes.The minute pores pose challenges in facilitating sufficient coolant supply and are susceptible to clogging.The feasibility of enhancing the transpiration cooling properties of C/SiC composites through the addition of artificial holes was analyzed.The structure and equivalent model of the artificial hole characterization unit were established.Flow ratios and effective permeability within the perforated composite were acquired.The effect of perforation method and mass flow rate on the effective heat transfer coefficient of composites was investigated.An empirical equation describing the variation of the heat transfer coefficient after perforation was fitted.Results show that for permeability characteristics,the dominant flow of cooling fluid occurs in the designed holes.In low-permeability materials with a permeability of 1×10^(-16) m^(2),the proportion of fluid flow of the composites’process hole drops to less than 0.1%after perforation,thereby rendering the flow of working material in this process hole negligible.Concerning heat transfer,adjusting perforation techniques can enhance composite material heat transfer efficiency.With the same permeability,altering perforation can boost body heat transfer coefficient by up to 154%.

关 键 词：C/SIC复合材料 热防护 传热传质 发汗冷却 人工孔 数值模拟 

分 类 号：V445[航空宇航科学与技术—飞行器设计]