基于CCD的蒸汽湿度及水滴直径测量

Application of CCD in Measuring Steam Moisture and Droplet Size

为了准确测量汽轮机末级蒸汽湿度及其空间分布,本文提出用CCD测量湿蒸汽的散射光强分布,并通过数值拟合得到汽轮机内部的蒸汽湿度和水滴直径。根据CCD成像规律以及散射光强的分布特点,建立了包括测量系统、汽轮机模拟系统在内的实验平台。用532nm的激光照射湿蒸汽,CCD拍摄得到2.6°-6.6°角度变化范围内的散射光强分布,并通过数值拟合得到蒸汽相对湿度变化范围0.7%-1.2%、水滴平均直径大小为1.4-1.6μm。实验结果表明：该测量方法可以用来测量汽轮机末级蒸汽湿度和水滴直径,并且实现了较大范围内散射光测量。实验结果直观地反映了汽轮机内部蒸汽湿度的变化规律,从而有力地证明CCD应用在蒸汽湿度测量中的可行性。

In order to accurately measure the steam moisture and droplet size, a new method is proposed to measure the light scattering in steam turbine, and by optimal numerical fitting, we can get the value of steam moisture distribution and droplet size. According to the characteristic of CCD imaging and light scattering theory, the experimental platform including the measurement system and simulation system of steam turbine is set up. The laser with the wavelength of 532nm is adopted to irradiate the moisture gas, and the light scattering distribution by the scale of 2.6°～6.6° is measured by CCD, so the steam moisture distribution（0.7%-1.2%） and average droplet size（1.4 -1.6μm） can be calculated by curve fitting. The experimental results indicate that this method can be used to measure steam moisture and droplet size, and the large scale can be achieved by using CCD. Furthermore, the experimental results also vividly reflect the varying rule of steam moisture and droplet size, so the feasibility of application of CCD technology in measure of steam moisture is supported strongly.