【作者】 王星；

【导师】 王玉璋；

【作者基本信息】 上海交通大学 ， 动力工程及工程热物理， 2014， 硕士

【摘要】 我国在实现经济和社会的可持续发展中正面临能源问题的重大挑战，以燃机为核心的发电系统具有高效、清洁、环保、低排放的优点，目前对于解决能源与环境问题具有明显的优势。热障涂层在燃机热端部件的热防护上具有巨大的应用价值，有利于提高燃气透平入口温度，提高燃机的循环效率与功率输出，降低单位功率燃气消耗，延长透平使用寿命，对于提高燃机运行的综合性能具有重要意义。热障涂层的应用为地面重型燃机高效、安全、可靠运行提供重要的保障，对于提升以燃机为核心的发电系统的能源转换效率，以及改善优化我国现有的能源结构有重要影响，具有重要的实际应用价值，值得深入研究。本文将对影响YSZ热障涂层隔热性能所涉及到的涂层的内部孔隙率以及层状与柱状微结构两个关键问题开展深入研究。为了对具有不同内部结构的涂层隔热性能进行研究，本文结合多孔介质的数值构造方法，获得了涂层的不同内部结构模型，并提出了建立在一定假设条件下的传热分析模型，开发了基于涂层骨架结构的有限差分方法与热格子波尔兹曼方法的模拟程序，对热障涂层的隔热性能以及涂层内能量传输过程进行研究。通过将模拟结果与理论可求解算例进行对比验证了程序的有效性。基于此程序，计算了涂层孔隙率、温度、孔隙大小、涂层的层状与柱状微结构对有效导热系数的影响，结果发现：孔径大小对涂层隔热性能影响不明显；涂层的导热系数随孔隙率的增加而降低；内部微结构对涂层有效导热系数具有重要影响；低孔隙率层状结构具有优异的隔热性能。同时本文还分析了影响涂层传热各环节中，不同因素对涂层隔热温度的影响规律。同时，本文以热障涂层电镜扫描图片为基础，建立真实的涂层结构模型，研究涂层内的传热过程。对由APS工艺获得的均匀结构涂层，在1150℃高温下经过不同时间烧结后，其结构以及孔隙率进行了统计分析，进而获得了涂层热导率随时间的变化关系。该项研究为涂层隔热性能的研究提供了新方法与思路，同时为优化涂层结构设计，提高其隔热性能提供参考依据。更多还原

【Abstract】 Energy issues have become top discussion of our country to maintainthe sustainable development of the economic and social. The power systemwith gas turbine as the core engine has the characters of high efficiency,clean, low emissions; it has shown great advantages of solving the energyand environment problem. Thermal barrier coatings (TBCs) have showngreat value in thermal protection of the high temperature region of the gasturbine, it can help to increase the inlet temperature of the turbine which isbeneficial for improving the cycle efficiency and the output power,decreasing the gas consumption of unit power, prolonging its service lifeand is of great importance in improving the comprehensive performance ofthe turbine. TBCs have shown application value in maintaining the turbineworking safely, efficiently, reliably; it can help to improve the energytransfer efficiency of the gas turbine and optimize the current energystructure of our country, it’s necessary to have further study of it. Theequivalent thermal conductivity of TBCs is highly related with two factors:the internal porosity and the inner structure of the coating, this paper willconduct an intensive research of the above focuses.We have established a simplified physical model to have an in-depthstudy of the thermal insulation ability and the heat transfer process of thecoating. Firstly, the coating models had different inner structure wereconstructed with a numerical method. Secondly, the thermal latticeBoltzmann method and the finite difference method were used to programthe simulation software. We verified the effectiveness of the software bycomparing the simulation results with theory solutions of a simplified case. The influence of the porosity, the pore diameter and the different innerstructure to the effective thermal conductivity of the coatings werecalculated by our software. The results also show: the influence of the porediameter to the thermal conductivity is not obvious; the inner micro-structures make a great difference to the thermal conductivity; the effectivethermal conductivity of the coatings decreases with the increase of theporosity obviously. The layered coatings with low porosity show excellentthermal insulation ability. This paper also analyzes the influence ofdifferent factors in the heat transfer process to the specified insulationtemperature.We also established a heat transfer research model which was based onthe real scanning electron microscopy picture of the coatings, the heattransfer in the different structure was studied. The coatings were producedby the APS technology while the inner structure is the uniform one, andthey were sintered at high temperature of1150℃for different time. Bywriting a program which was used to simulate the temperature field ofthose models, we can easily get the changing relationship of thermalconductivity with the sintered time. These studies provide a new way tohave the numerical research of effective thermal conductivity of the TBCs,it also provide reference for the optimization of the coatings structure.更多还原