航空发动机燃烧室出口温度场和燃气组分分布的在线监测技术研究

A scientific instrument will be designed by fusing a tunable diode laser absorbtion spectroscopy (TDLAS)-based tomography system and an electrical capacitance tomography (ECT) system. The instrument can be used to monitor the temperature field and gas component distribution at the aero-engine combustor exit in an on-line manner. This can not only provide with valid data and references for aero-engine combustor design, but also provide with a reliable scheme to monitor the health status of the aero-engine, which helps to prolong the service life and improve the reliability of the aero-engine. Firstly, the temperature field, gas concentration distribution at the aero-engine combustor exit are calculated by means of computational fluid dynamics simulation. The correlation between the temperature field and gas component distribution at the aero-engine combustor exit will be studied and a correlation model will be established between them. A TDLAS-based tomography system will be constructed to measure the temperature field, gas concentration distribution at the aero-engine combustor exit in an on-line manner. The measurement data in the experiment are then used to validate and modify the simulation model for combustion and the correlation model between the temperature field and the gas concentration distribution at the aero-engine combustor exit. Secondly, the temperature field and the gas concentration distribution are employed as the constraints in the multi-physical field simulations to calculate the permittivity distribution at the combustor exit. Experimental data obtained from the ECT are used for model verification and modification. Thirdly, by the aid of the verified and modified models, both simulation and experimental data from the TDLAS tomography system and the ECT system will be fused to study and establish the relationship between the permittivity distribution and the temperature field and gas component distribution at the combustor exit. The relationship will then be used to explore the feasibility of using the images obtained from ECT to reconstruct the temperature field and gas component distribution in the combustor exit area.

研制基于可调谐二极管激光吸收光谱（TDLAS）层析成像系统和电容层析成像（ECT）系统相融合的科学仪器，用于航空发动机燃烧室出口温度场和燃气组分分布的在线监测研究，可为航空发动机燃烧室的优化设计及健康状况的诊断提供实测数据和有效参考依据。首先，本项目通过计算流体力学仿真计算燃烧室出口区域的温度场和燃气组分分布，研究实际工况条件下两者的相关性并建立二者之间的关联模型；研制TDLAS层析成像系统，实现发动机燃烧室出口温度场和燃气组分分布的在线监测，并验证完善燃烧过程仿真模型及所建立的关联模型。其次，将温度场、燃气组分分布作为约束条件，结合多物理场仿真，计算燃烧室出口区域的介电常数分布，并通过ECT实测数据进行实验修正。再次，借助修正后模型，将TDLAS层析成像和ECT的仿真和实测数据相融合，研究介电常数分布和温度场、燃气组分分布的关系，从而探索采用ECT重建图像恢复温度场与燃气组分分布的能力。

本项目针对航空发动机燃烧室出口温度和燃气组分分布在线监测的难题，将可调谐二极管激光吸收光谱技术和电容层析成像技术相结合，重建了燃烧室出口温度、燃气组分和介电常数分布。.基于可调谐二极管激光吸收光谱技术的层析成像系统具有响应速度快、数据准确、可对多个分布参数同时成像等优点，该技术适用于高温燃气组分和温度分布的在线测量。电容层析成像技术可在采用非侵入式测量手段获得断面上介电常数的二维分布灰度图像，清晰、准确、直观地展现被测物体内部的结构特征。本项目将两种技术有机融合，为航空发动机燃烧室出口的燃气组分及温度分布的监测提供一种崭新的在线监测手段。.项目执行过程中，项目组成员首先对航空发动机燃烧室模型旋流燃烧器和串联凹腔燃烧室进行仿真研究，为传感器设计提供了依据；对燃烧实验平台的常见研究对象——平焰燃烧炉及本生灯进行了数值模拟，与实验室内的测量结果相互验证。而后，设计并研制了激光吸收光谱技术的控制电路、采集系统和片上数据采集系统，结合燃气组分的吸收谱线特性，实现了吸收率线型函数的片上拟合。在旋流火焰燃烧平台上实验验证并研究了激光吸收光谱技术应用于温度和燃气组分分布的层析成像重建理论及方法。设计并研制了高速数字式电容层析成像系统，通过监测本生灯点火和熄火过程中的介电常数变化验证了系统性能。基于对温度、阻抗分布和激光吸收光谱的研究，设计了激光吸收光谱层析成像与电容层析成像融合传感器，并同时获得了火焰的温度和介电常数分布图像。.受项目支持，项目组成员共发表学术论文28篇，其中SCI索引论文20篇，发展了激光吸收光谱和电容层析成像技术，丰富了航空发动机燃烧室出口的温度和燃气组分分布检测理论，具有重要的学术意义及应用价值。项目已授权发明专利29项，发明并研制的激光吸收光谱层析成像与电容层析成像融合传感系统将进一步推进研究航空发动机内部的燃烧机理研究。