基于光散射法强度调制的颗粒物浓度检测技术研究

The Research on Particulate Matter Concentration Detection Technology Based on Light Scattering Intensity Modulation

摘要: 颗粒物浓度的实时、准确测量一直是国内外研究的热点，尤其在环境监测、工业排放和车间生产中，抗干扰和低浓度颗粒物的有效检测技术越来越受到关注。本文提出了一种基于光散射法强度调制的颗粒物检测方法，以解决外界环境光干扰问题。通过理论分析，探讨了颗粒物粒径、光源波长和散射角度对散射光强度与分布的影响。在光散射法的基础上，采用650 nm激光作为光源，构建了光强度调制颗粒浓度检测系统。系统通过压控恒流源对激光进行12 Hz的强度调制，并通过锁相放大器锁定同频信号并滤除散射信号。对粒径为1 μm的单分散SiO₂粉末进行了浓度为25~17,500 mg/m³范围内的散射实验。实验结果表明，与传统检测方法相比，该系统显著降低了外界环境光对检测结果的干扰。

Abstract: Real-time and accurate measurement of particulate matter concentration has been a hot research topic both domestically and internationally, especially in environmental monitoring, industrial emissions, and workshop production. Effective detection of low-concentration particles and anti-interference technology have garnered increasing attention. This paper proposes a particulate matter detection method based on light scattering intensity modulation to address the issue of external light interference. The theoretical analysis explores the effects of particle size, light source wavelength, and scattering angle on the intensity and distribution of scattered light. Based on the light scattering method, a particulate concentration detection system is constructed using a 650 nm laser as the light source. The system modulates the laser intensity at a frequency of 12 Hz using a voltage-controlled constant current source, and a phase-locked amplifier is used to lock the same-frequency signal and filter out scattering signals. Scattering experiments were conducted with monodisperse SiO₂ powder of 1 μm particle size in a concentration range of 25~17,500 mg/m³. The experimental results show that, compared to traditional detection methods, this system significantly reduces the interference of external environmental light on the detection results.