烟尘浓度光散射测量技术研究

发布时间：2019-02-11 20:02

【摘要】：燃烧过程中产生的大量烟尘排放,是导致大气环境污染的主要原因,实现烟尘排放的准确监测对环境保护与管理有重要意义。然而,现有的烟尘浓度测量技术因其内在的缺陷,往往难以运用于恶劣的工程应用环境。光散射法作为一种高精度、非侵入的实时在线测量方法,发展十分迅速。本文主要研究了一种无需预知粒径的烟尘浓度光散射积分测量技术,通过大量实验验证了其可行性,并系统分析了测量系统的精确度、误差来源和浓度适用范围。首先介绍了光散射理论,验证了Mie理论与Fraunhofer理论的近似性,在此基础上推导了无需预知粒径的散射积分法。然后根据空间滤波理论和高斯光束的聚焦、准直理论,建立了基于光散射积分法烟尘浓度测量系统,并介绍了系统元器件的选择依据。基于数值模拟计算了光散射测量系统的误差,分析了粒径分布、颗粒折射率及散射光接收角范围等参数对浓度测量误差的影响。结果验证了散射积分法无需预知粒径的特点,并为测量系统的散射角度范围的选择提供了设计依据。利用针孔测试了系统性能,校准了测量系统的放大倍率和散射角度参数,并研究了测量系统的线性动态范围。然后,利用标准颗粒溶液对测量系统进行了实验研究。结果证明了散射积分法烟尘浓度测量的可行性。最后进行了低浓度颗粒测量实验,研究了系统的浓度测量下限及其影响因素。
[Abstract]:A large amount of smoke and dust emission from combustion process is the main cause of atmospheric environmental pollution. It is of great significance to realize accurate monitoring of smoke and dust emission for environmental protection and management. However, the existing smoke concentration measurement technology is often difficult to be used in the harsh engineering environment because of its inherent defects. As a high-precision, non-intrusive real-time online measurement method, light scattering method has been developed rapidly. In this paper, a light scattering integral measurement technique of smoke concentration without predicting particle size is studied, and its feasibility is verified by a large number of experiments. The accuracy, error source and applicable range of concentration of the measurement system are systematically analyzed. Firstly, the theory of light scattering is introduced, and the approximation between Mie theory and Fraunhofer theory is verified. On this basis, a scattering integration method is derived without the need of predicting the particle size. Then, based on the spatial filtering theory, focusing and collimation theory of Gao Si beam, a smoke concentration measurement system based on light scattering integration method is established, and the selection basis of system components is introduced. The error of light scattering measurement system is calculated based on numerical simulation. The influence of particle size distribution, refractive index of particles and the range of receiving angle of scattering light on the error of concentration measurement is analyzed. The results show that the scattering integration method does not need to predict the particle size and provides a design basis for the selection of the scattering angle range of the measurement system. The system performance was tested by pinhole, the magnification and scattering angle parameters of the measurement system were calibrated, and the linear dynamic range of the measurement system was studied. Then, the measurement system is studied by using standard particle solution. The results show that the scattering integration method is feasible to measure the smoke concentration. Finally, the low concentration particle measurement experiment was carried out, and the lower limit of concentration measurement and its influencing factors were studied.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X831

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