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温度分布在线实时测量对于燃烧过程优化和污染物控制具有重要意义,针对以往非接触三维温度分布重建过程的耗时性问题和忽略壁面辐射的不足,本文提出了一种新的离散重建模型,用于三维吸收、发射和散射性高温燃烧介质以及壁面温度的快速联合非接触测量.该模型以四个CCD(Charge Coupled Device)为测量传感器,通过构建辐射逆问题求解方程,从CCD输出的辐射投影图像重建温度分布.介质中不同投影方向内的辐射传递过程通过离散传递法来描述,介质的散射和壁面反射则通过离散坐标法来近似.离散后计算局部辐射强度的病态方程通过最小二乘余量法来求解,论文对其计算速度进行了优化.通过非对称温度分布测量算例分析了该模型的有效性,讨论了测量噪音、介质和壁面辐射特性对重建精度的影响,并与其他方法对比分析了模型的重建速度.计算结果表明本文提出的离散模型可以有效地用于大型高温燃烧介质和壁面温度分布的联合非接触测量.即使在有噪声的情况下,该模型也能获得准确的测量结果,与其他计算方法相比,采用改进的最小二乘余量法,能有效地提高温度分布的重建计算速度.
Real-time measurement of temperature distribution is of great significance for combustion process optimization and pollutant control. Aiming at the time-consuming problem of non-contact three-dimensional temperature distribution reconstruction and the neglect of wall radiation, a new discrete reconstruction model In the three-dimensional absorption, emission and scattering of high-temperature combustion medium and the wall temperature of the rapid joint non-contact measurement of the model with four CCD (Charge Coupled Device) as the measurement sensor, by solving the equations to solve the radiation inverse problem, the radiation output from the CCD projection Image reconstruction temperature distribution. Radiation transfer process in different projection directions is described by discrete transfer method. Dispersion and wall reflection are approximated by discrete coordinate method. The pathological equations for calculating local radiation intensity after dispersion are calculated by least squares The method is used to solve the problem and the computational speed is optimized.The effectiveness of this model is analyzed by an example of measurement of asymmetric temperature distribution.The influence of measurement noise, medium and wall radiation on reconstruction accuracy is discussed and compared with other methods The reconstruction speed of the model is compared and analyzed. The calculation results show that this paper proposes The discrete model can be effectively used for the joint non-contact measurement of large-scale high-temperature combustion media and wall temperature distribution, and the model can obtain accurate measurement results even under noisy conditions. Compared with other calculation methods, the improved model Least square method, can effectively improve the temperature distribution of the reconstruction calculation speed.