【作者】 李林；

【导师】 陈德华； 张志刚；

【作者基本信息】 电子科技大学 ， 电子信息（专业学位）， 2025， 硕士

【摘要】 超燃冲压发动机作为高超声速飞行的核心推进系统,其燃烧室内火焰温度的精确测量对于超声速燃烧特性研究和发动机热防护设计至关重要。然而,燃烧室内部流场复杂,受高温、高压、高速流动以及湍流混合、激波/附面层相互作用影响,燃烧区域高度非均匀。此外,燃料在燃烧室内驻留时间仅为毫秒级,恶劣的条件和极短的观测时间对测温技术的环境适应性和响应速度提出严苛要求。传统接触式测温方法干扰流场且响应迟滞,而基于激光光谱的测温手段成本高昂,限制了其工程应用。针对上述问题,本文提出一种基于比色测温原理的瞬态火焰温度场摄影测量方法。主要研究内容包括:1.设计并搭建基于CMOS高速摄影的非接触式温度测量系统,采用高精度黑体炉进行标定,构建灰度-温度响应模型,并利用高斯二乘法拟合比色测温多项式。标定实验结果表明,该系统在1073 K-2573 K范围内的最大绝对误差为25.41 K,最大相对误差为1.87%,能够有效满足超燃冲压发动机燃烧室火焰测温精度需求。2.针对复杂背景下火焰区域提取问题,构建了一种融合多特征的火焰混合分割模型。该模型利用多通道颜色特征实现火焰主体提取与抑制干扰,并通过带约束条件的并联融合策略平衡漏分割率与误分割率。随后,结合区域生长算法精细提取火焰轮廓并去除红烟干扰,最终采用形态学操作填充掩膜孔洞并优化边界。实验表明,该方法在复杂火焰场景中具备较高的分割准确性和稳定性。3.基于超燃冲压发动机自由射流试验平台,模拟氢燃料超燃冲压发动机在马赫数10、动压30 kPa条件下的飞行状态,开展了燃烧室火焰温度测量实验。将高速相机捕获的燃烧图像处理后利用拟合多项式重建火焰二维温度场。通过对短时爆燃与持续稳定燃烧两种典型工况的温度场对比分析发现,短时爆燃场景下温度场波动剧烈,存在明显的非均匀性与温度分层;持续稳定燃烧时则表现为整体温度分布较为均匀且具有明显的时间连续性。此外,进一步获取了稳定燃烧过程最高温度、平均温度与高温质心位置的时序演变特征,并通过概率统计刻画主燃区的空间稳定性。研究结果验证了基于比色测温原理的非接触式摄影测温技术在超燃冲压发动机燃烧室温度测量中的可行性,并为超声速燃烧火焰温度场诊断提供了一种高性价比、高时空分辨率的测量手段。更多还原

【Abstract】 As a critical propulsion system for hypersonic flight,scramjet engines necessitate precise flame temperature measurement within their combustion chambers to facilitate research on supersonic combustion characteristics and thermal protection design.However,the complex internal flow field of the combustion chamber—characterized by high temperature,high pressure,high-velocity flows,turbulent mixing,and shock wave/boundary layer interactions—results in highly heterogeneous combustion regions.Additionally,the residence time of fuel within the combustion chamber is only on the order of milliseconds,placing stringent requirements on the environmental adaptability and response speed of temperature measurement techniques.Traditional contact-based methods interfere with the flow field and exhibit delayed responses,whereas laser-based spectral techniques,despite their accuracy,incur high costs that limit their practical engineering applications.To address these challenges,a transient flame temperature field measurement methodology based on colorimetric pyrometry was proposed.The primary research contents include:1.Design and construction of a non-contact temperature measurement system utilizing high-speed CMOS photography.The system was calibrated using a high-precision blackbody furnace to establish a grayscale-temperature response model,from which a polynomial for colorimetric pyrometry was derived using Gaussian least-squares fitting.Calibration results indicated a maximum absolute error of 25.41 K and a maximum relative error of 1.87%within the temperature range of 1073 K to 2573 K,effectively meeting the temperature measurement accuracy requirements for scramjet engine combustion chambers.2.To address flame region extraction under complex backgrounds,a hybrid flame segmentation model integrating multiple features was developed.The model employs multi-channel color features to extract flame regions while suppressing interference,utilizing a constrained parallel fusion strategy to balance under-segmentation and over-segmentation.Subsequently,a region-growing algorithm refined flame contours and eliminated interference from red smoke.Finally,morphological operations filled mask holes and optimized boundaries.Experimental results demonstrated that this method achieved high segmentation accuracy and stability in complex flame scenarios.3.Based on the free-jet experimental platform for scramjet engines,flame temperature measurements in the combustion chamber were conducted under simulated flight conditions of a hydrogen-fueled scramjet engine at Mach 10 and a dynamic pressure of 30 kPa.Flame images captured by the high-speed camera were processed,and the two-dimensional temperature field was reconstructed using the fitted polynomial.Comparative analysis between short-duration deflagration and sustained stable combustion revealed pronounced temperature fluctuations and heterogeneity under short-duration conditions,whereas stable combustion exhibited a relatively uniform and temporally continuous temperature distribution.Additionally,temporal evolution characteristics of maximum temperature,average temperature,and high-temperature centroid location during stable combustion were further analyzed,and spatial stability of the primary combustion zone was statistically characterized.The results validated the feasibility of non-contact photographic temperature measurement technology based on colorimetric pyrometry for scramjet combustion chamber applications,providing a cost-effective measurement method with high temporal and spatial resolution for diagnosing supersonic combustion flame temperature fields.更多还原