【作者】 田贻丽；

【导师】 谢利利；

【作者基本信息】 重庆大学 ， 光学工程， 2003， 硕士

【摘要】 现代工业生产中，粉尘浓度测量已经越来越重要，在许多行业中它都占有相当重要的作用。目前国内外测量粉尘浓度的方法各式各样，但是大致可以分为两大类：即基于取样的方法进行测量和基于非取样的方法进行测量。随着科学技术的快速发展，非取样方法中的利用光电的方法进行浓度测量的优点已经越来越突出了。目前，人们所用的光电测尘方法中大多数是利用的朗伯－比尔定律消光的方法，即透射的方法。光透射的方法在测量高浓度粉尘时效果较好，但是在粉尘浓度较低时，它便无法得到较好的测量结果。为了解决透射法无法很好测量低浓度粉尘的问题，本文主要研究了基于光散射测量粉尘浓度的方法，该方法能解决上面的低浓度测量时的问题。文中利用Mie散射理论，推导出通过计算一定散射角度的散射光强来计算粉尘浓度的测量方法。并且在文中将该方法与前面所讲的光透射的方法进行了比较。文章还对测量单粒径尘粒和具有尺寸分布尘粒的两种情况进行了计算机模拟。并对模拟后得到的数据进行了分析、处理，研究了测量时散射角度对测量浓度结果的影响，以及测量角度的选取问题。文中根据衍射法求取平均粒度的方法，提出了用两个不同散射角的散射光强比求取平均粒度的方法，解决了衍射法测平均粒度的缺点。并且，经过大量的计算，分析了这种利用散射的测量方法在不同粒径范围的情况下测量角度的选取。然后本文还分析了将具有尺寸分布尘粒的浓度测量按单一粒径尘粒进行近似测量的计算情况，并比较了它们在不同粒度、不同测量角度、不同分布参数情况下的差异。对于小粒径的情况，测量角度相对要选大些较好。对于低浓度的情况，测量角度也较大为好。最后，文章进行了测量系统的设计，对测量系统的光路部分、电路部分中的微信号放大电路进行了设计。并进行了光散射法测量平均粒径和浓度的实验以及放大电路实验。文中列出了部分测量数据。实验结果表明：该文所提出的用光散射法测量粉尘的方案是切实可行的，它具有广阔的实际应用前景。更多还原

【Abstract】 In today’s industry, powder concentration measurement has become more and more important and played a significant part in many conditions. At present, there are a lot of methods to measure powder concentration. They can be generally classified in two classes, one is based on sampling, and the other is not need to sample.With the promptly development of science and technology, the advantage of the opto-electric(OE) method which do not need sample has stood out. Nowadays the extinction method of the OE measurement, which is based on lamb-beer theory, has been generally applied. Though it effect well when powder concentration is high, it cannot get a good measurement result when the concentration is low.To solve this problem, the method based on scattering is deduced in this paper. This method can work effectively when the concentration is low. Based on Mie theory，this method measure the concentration by calculating the scattering light intensity. And we compared it with the extinction method.We simulated the measurement of monodisperse powder and polydisperse powder. Analyzed the simulation result. Studied the relationship between scattering angle and concentration measurement result to choose the best measuring angle. According to the mean size measurement based on diffraction, we put forward a new method by calculating the ratio of two scattering light intensity at different scattering angle, which can solve the problem caused by the diffraction method. Then by a lot of calculation, we dealt with the problem about how to choose scattering angle when measure the concentration at different size . Then we also presented the simple way to solve the polydisperse powder concentration by calculate it as monodisperse powder, compared the measurement results which were got at different diameter , scattering angle and distribution. Choosed the large scattering angle when the powder diameter is small or when the powder concentration is low.At last, discussed the light path and the circuit of the measurement system ,especially the amplifier circuit. After the experiments, partial result has been listed in this paper. The result showed that the concentration measurement discussed in this paper is feasible. And I believe that it will be applied widely.更多还原