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类型 基础研究 预答辩日期 2018-01-08
开始(开题)日期 2016-03-24 论文结束日期 2017-11-13
地点 礼西楼会议室 论文选题来源 973、863项目     论文字数 8.3 (万字)
题目 基于光场成像的火焰三维温度场测量方法研究
主题词 光场成像,发光火焰,三维温度场,微透镜阵列,燃烧
摘要 燃烧广泛存在于日常生活和钢铁、冶金、电站、航空航天等工业生产过程。燃烧火焰三维温度场的重建研究,为探究燃烧化学的本质、调整燃烧方式、优化燃烧过程以及控制燃烧污染物生成等提供重要数据支撑,具有重要的科学意义和应用价值。针对现有火焰温度测量系统复杂、调试繁琐等问题以及相应测量装置在辐射信息采样与重建方面的不足,本文提出了基于光场成像技术的火焰三维温度场测量方法,开展了系统的理论与实验研究。 提出了火焰辐射光场成像光线追迹方法,介绍了火焰内部辐射传输过程及光线辐射强度的计算方法,耦合光场成像与火焰辐射传输模型,建立了火焰辐射光场成像数学模型。计算了不同类型光场相机和不同火焰物性参数下的火焰辐射光场图像,提出了火焰辐射光场图像有效像素和像素利用率的概念,以衡量图像探测器采集火焰辐射信息的能力,计算分析了火焰不同深度处的重聚焦图像。结果表明,光场成像系统能够采集火焰不同方向、不同位置的三维辐射信息。在火焰有限的体积范围内,火焰内部不同深度处的重聚焦图像之间差异较小。 提出了基于光场成像的火焰三维温度场重建策略与方法。介绍了线性优化算法LSQR(Least Squares via QR factorization,最小二乘QR分解)和NNLS(非负最小二乘,Non-negative Least Squares)以及非线性优化算法Levenberg-Marquardt的基本原理与算法,求解了光场成像火焰三维温度场重建中的辐射传输方程。在此基础上,针对辐射传输方程中吸收系数未知的问题,提出了NNLS-LMBC混合算法,同时重构火焰的温度及吸收系数。设置了四种不同温度和吸收系数分布的火焰,计算了不同条件下的火焰光场图像,进行了光场成像火焰三维温度场重建数值模拟。结果表明:四种情况下,LMBC-NNLS混合算法可实现火焰温度及吸收系数同时重构,重建结果的相对误差小于0.1,表明LMBC-NNLS混合算法具有较高的可靠性和精度。 以单个像素为采样单元,提出了采样域(SR,Sampling Region)、单位采样角(SAPU,Sampling Angle Per Unit)和采样角(SA,Sampling Angle)的概念,以衡量单个像素火焰辐射光场采样的单方向性。定义了采样光线的概念,比较了不同微透镜与探测面距离及不同类型的微透镜阵列(单焦距微透镜阵列和多焦距微透镜阵列)的采样光线在火焰内部的空间分布,分析了不同参数下火焰光场图像及火焰三维温度场重建结果。结果表明:相比于光场相机2.0,光场相机1.0火焰辐射采样光线空间位置分布不均匀,不利于火焰温度重建。相比于多焦距微透镜阵,单焦距微透镜阵列采样光线空间位置分布更均匀,因而,其火焰三维温度场重建结果优于多焦距微透镜阵列。 研制了基于光场成像的火焰三维温度场测量系统,评价了系统组件的基本性能。提出了聚焦光场相机几何参数标定新方法,建立了基于光场图像的聚焦光场相机标定模型,利用Levenberg-Marquardt算法求解了相机几何参数,进一步结合光场相机F数匹配特性获得了标定参数,并与全聚焦图像的标定结果进行了比较验证。开展了光场相机图像探测器辐射强度标定实验研究。几何标定结果的重投影误差小于7个像素,证明了提出的聚焦光场相机标定方法的可行性。 开展了光场成像火焰三维温度测量方法实验评价及实际应用研究。设计加工了同流燃烧器(Co-flow Burner),利用光场成像火焰三维温度场测量系统,采集了火焰光场图像,根据光场成像火焰三维温度场重建算法,重建了乙烯层流扩散火焰的三维温度分布,将重建结果与热电偶测量结果进行了对比评价。分析了测量结果的误差来源,评价了测量系统的精确度。结果表明:与热电偶温度测量结果吻合较好,两种测量结果最大相差150.9 K,表明了光场成像火焰三维温度场重建方法的可行性和可靠性。并进行了流化床生物质颗粒燃烧火焰的三维温度场测量实际应用研究。结果表明,光场成像火焰温度测量系统能够进行流化床生物质颗粒燃烧火焰温度及吸收系数同时重建,为煤粉/生物质颗粒燃烧可视化实验提供了新的测试方法和实验手段。
英文题目 Three-dimensional temperature measurement of flame based on light field imaging
英文主题词 Light field imaging, Luminous flame, Three-dimensional temperature field, Microlens array, Combustion
英文摘要 Combustion is widely applied in daily activities and industries such as steel, metallurgy, power plants, and aerospace. The investigation of the three-dimensional temperature (3D) field reconstruction of flames would support many studies such as the investigation of the nature of combustion chemistry, adjusting the combustion mode, optimizing the combustion process, and controlling combustion pollutants, and therefore, it is significant and valuable in science and practical applications. Existing flame-temperature measurement methods and systems are complex in terms of system setup and installation, and also limited in terms of 3D radiation sampling and reconstruction. Therefore, 3D temperature measurement methods for the flames are proposed based on the light field imaging technique in this study. A systematic investigation is carried out theoretically and experimentally. Tracing methods for the radiation emitted from flames based on light field imaging are proposed. The principles of calculating the radiative transfer process inside the flame and the intensity of radiative rays are introduced. The technique of light field imaging and radiative transfer model are combined to develop the mathematical model of radiative light field imaging. Light field images of flames are calculated for different types of light field cameras and different radiative properties of flames. The concepts of effective pixels and utilization rate of pixels are proposed for the light field images of flames to evaluate the capacity of radiation sampling. The refocused images of flames at different depths are also calculated and compared. The simulation results indicate that the light field camera can be applied to sample the 3D radiation information of the flame. A slight difference can be observed among the refocused images at different depths inside the flame, which is due to the limited volume of the flame. The strategy and method to reconstruct the 3D flame temperature field based on the light field imaging is proposed. Linear optimization algorithms of LSQR (least squares via QR factorization, LSQR) and NNLS (non-negative least squares) and non-linear optimization algorithms of Levenberg-Marquardt are described to solve radiative transfer equations in the 3D flame temperature field reconstruction bead on the light field imaging. On this basis, a hybrid algorithm of LMBC (Levenberg-Marquardt method with Boundary Constraint) and NNLS is proposed for the unknown absorption coefficient in radiative transfer equations. The LMBC-NNLS algorithm is applied to reconstruct the temperature and absorption coefficient of the flame simultaneously. In numerical simulations, four cases of different distributions of temperature and absorption coefficient are set. For the four cases, the light field images of the flames are calculated and the 3D flame temperatures are reconstructed. The results indicate that the LMBC-NNLS algorithm is applicable to the simultaneous reconstruction of the temperature and absorption coefficient. The relative errors of the four cases are all less than 0.1. The LMBC-NNLS algorithm is accurate and reliable. A single pixel is considered as one sampling unit. On this basis, the concepts of sampling region (SR), sampling angle per unit (SAPU), and sampling angle (SA) are proposed to evaluate the directional accuracy of the radiation sampling. The concept of the sampling ray is defined. The distributions of the sampling rays for different distances between the microlens array and photosensor and different microlens arrays (single focal length and multiple focal lengths) are compared inside the flame. The light field flame images and reconstruction results of different parameters are analyzed and compared. Compared to light field camera 2.0, the distributions of sampling rays of light field camera 1.0 are less homogeneous and therefore are disadvantageous to the temperature reconstruction of flames. Compared to the microlens array with multiple focal lengths, the distributions of sampling rays are more homogeneous, and therefore, the reconstruction results are better for the microlens array with a single focal length. The measurement system of the 3D flame temperature field bead on light field imaging is developed. The basic performance of the elements in the measurement system is evaluated. A novel calibration method for the focused light field camera is proposed. The calibration model is developed based on the light field images. The specific parameters to be calibrated are further calculated according to the characteristic of the matching F-numbers. The calibration results are compared and validated using total focused images. The experiments for intensity calibration are investigated and the errors of the intensity calibration are calculated. The reprojection errors of the geometric calibration are below 7 pixels. The method to calibrate the focused light field camera is feasible. The experimental evaluation and practical application of the 3D flame temperature field reconstruction bead on light field imaging are carried out. A co-flow burner and combustion system are designed and fabricated. The measurement system of 3D flame temperature field bead on light field imaging is utilized to capture the light field images of flames. The 3D distributions of the temperature and absorption coefficients of ethylene flames are reconstructed using the proposed hybrid LMBC-NNLS algorithm. The reconstruction results using the LMBC-NNLS algorithm and thermocouple results are compared. A good agreement is observed between the two results, and the maximum difference is 150.9 K. The accuracy and reliability of the method to reconstruct the 3D flame temperature field bead on light field imaging are validated. The main error sources of the reconstruction results are analyzed to evaluate the accuracy. The practical application of the 3D temperature field reconstruction of biomass flames on a fluidized bed is investigated. The results demonstrate that the measurement system bead on the light field imaging can be utilized for the temperature field reconstruction of biomass flames. Novel investigation methods were provided for visualization experiments on the combustion of biomass or coal particles.
学术讨论
主办单位时间地点报告人报告主题
东南大学 2016年9月15日 南京东南大学四牌楼校区礼西楼会议室 王胜南 静电对AC-Based ECT的影响
东南大学 2016年12月15日 南京东南大学四牌楼校区礼西楼会议室 赵文超 基于光场相机的火焰分层成像
东南大学 2015年4月18日 南京东南大学四牌楼校区礼西楼会议室 孙俊阳 一种基于光场图像的聚焦光场
哈尔滨工业大学 2014年12月30日 哈尔滨市哈尔滨工业大学动力楼515 时红艳 光场成像与四维光场重建
东南大学 2014年11月12日 南京东南大学四牌楼校区礼西楼会议室 孙俊 基于光场成像技术的火焰三维温度场测量技术的研究
东南大学 2016年3月2日 南京东南大学四牌楼校区礼西楼会议室 孙俊 基于光场相机的火焰辐射场采样分析
东南大学 2016年10月02日 南京东南大学四牌楼校区礼西楼会议室 孙俊 多焦距微透镜阵列光场成像火焰三维温度场测量
东南大学 2017年10月25日 南京东南大学四牌楼校区礼西楼会议室 孙俊 多光场相机双峰火焰三维温度场重建研究及留学交流总结
美国西北大学计算成像实验室 2017年4月25日 美国伊利诺伊州,Evanston,西北大学,科技楼323 孙俊 3-D Temperature Reconstruction of the Flame Using a Single Light Field Camera
东南大学 2015年10月16日 南京东南大学四牌楼校区礼西楼会议室 刘煜东 两代光场相机的建模与分析
     
学术会议
会议名称时间地点本人报告本人报告题目
第9届国际多相流测试技术会议 2015年9月22至26日 日本北海道札幌北海道大学 3-D Flame Temperature Field Measurement Using a Single Lightfield Camera
2016年IEEE国际仪器与测量技术大会 2016年5月23至26日 台北国际会议中心 Geometric Calibration of Focused Light Field Camera For 3-D Flame Temperature Measurement
2015工程热物理年会多相流分会 2015年11月13至15日 南京华东饭店D 楼 基于单光场相机的火焰三维温度场测量方法研究
2016工程热物理年会多相流分会 2016年11月12至14日 广州珠江饭店 多焦距微透镜阵列光场成像火焰三维温度场测量
     
代表作
论文名称
Three-dimensional temperature field measurement of flame using a single light field camera
A novel calibration method of focused light field camera for 3-D reconstruction of flame temperature
Geometric Calibration of Focused Light Field Camera For 3-D Flame Temperature Measurement
多焦距微透镜阵列光场成像火焰三维温度场测量
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
毛军逵 正高 教授 博导 南京航空航天大学
韩省思 正高 教授 博导 南京航空航天大学
吕剑虹 正高 教授 博导 东南大学
盛昌栋 正高 教授 博导 东南大学
段伦博 副高 副教授 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
王沛 其他 工程师 东南大学