喷雾流场液滴参数全场彩虹技术与消光法融合的二维多点测量方法研究

Spray is widely used in energy and environment fields, such as processes of cooling, combustion etc. The concentration, temperature and size distribution of spray droplets influence operation safety and efficiency in the industrial process. So the online measurement methods for spray field with multi-point and multi-parameter performance have important guiding significance to the study of atomization mechanism and optimization of spray equipment. Therefore on the basis of previous investigation on single-point global rainbow refractometry, this project aims to build an imaging system based on a two dimensional array of apertures and mirrors and to propose an improved inversion algorithm. Thus refractive indices and size distributions of droplets at several locations on a two-dimensional plane can be determined accurately. Also the physical parameters (temperature, component concentration etc.) related to refractive index can be characterized indirectly. On the basis of previous investigation on extinction method, this project aims to propose a fusion algorithm based on global rainbow refractometry and extinction. Thus in the fusion algorithm, the droplet concentration in the spray field can be determined by extinction method. The size and refractive index of the droplets used for the determination of droplet concentration is obtained with global rainbow refractometry. Some nozzles widely used in energy and environment fields are taken for experimental research in the processes of cooling, burning etc. With the ultimate achievements of the project, a novel global rainbow refractometry for multi-parameter and multi-point measurement of spray droplets is expected to be presented, and the foundation for future development of test equipment can be established.

雾化广泛地应用于燃烧、冷却等能源与环境领域的诸多过程。雾化液滴的浓度、温度、粒径分布等参数显著地影响工业过程的安全和效率，因此喷雾流场液滴的多参数、多点、同时在线测量，对研究雾化机理及优化喷雾系统具有重要的指导意义。为此本项申请在前期单点全场彩虹技术的研究基础上，构建基于二维光阑-平面镜阵列的成像系统，以及提出改进反演算法，实现喷雾流场液滴折射率、粒径分布的二维多点全场彩虹在线测量方法，并间接表征与折射率有关的液滴温度、组分浓度等信息；在前期消光法的研究基础上，建立全场彩虹技术与消光法融合的测量系统和反演算法，则消光法可以利用全场彩虹技术测得的液滴粒径、折射率，测量喷雾流场的液滴浓度。最后基于建立的测量系统，选取能源环境领域常用的雾化喷嘴，对冷却、燃烧等过程中的喷雾进行实验研究。基于本项申请的成果，有望建立一套较为完整的喷雾流场多点多参数测量方法和系统，为后期测试设备的开发提供基础。

雾化广泛地应用于燃烧、冷却等能源与环境领域的诸多过程。雾化液滴的浓度、温度、粒径分布等参数显著地影响工业过程的安全和效率，因此喷雾流场液滴的多参数同时在线测量，对研究雾化机理及优化喷雾系统具有重要的指导意义。为此本项申请在前期全场彩虹技术的研究基础上，改进光学测量系统，以及提出改进反演算法，实现喷雾流场液滴折射率、粒径分布的全场彩虹在线测量方法，并间接表征与折射率有关的液滴温度、组分浓度等信息。粒径的测量误差约为5%，折射率测量误差小于0.001。在前期Mie理论、Nussenzveig理论的研究基础上，建立基于全场彩虹技术的液滴内不温度梯度反演算法，实现传热过程中液滴内部温度提的变化测量。最后基于建立的测量系统，选取能源环境领域常用的雾化喷嘴，对冷却、燃烧等过程中的喷雾进行实验研究。结果表明，随着传热过程的进行，测得的温度梯度随着时间逐渐变陡，温度的测量误差小于5℃。