多声道多普勒超声波污水流量测量技术研究

发布时间：2018-01-03 23:07

本文关键词：多声道多普勒超声波污水流量测量技术研究　出处：《东华理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,随着我国经济的飞速发展,环境污染问题日渐突显,特别是水资源污染问题。为了改善这种现状,实现水资源的可持续利用,需要通过对污水排放情况进行更加精确的实时监测,来评估水资源利用的环保水平,因此对污水流量的计量技术提出了新的要求。本文基于超声波多普勒效应理论,建立了污水流量测量的数学模型。推导了超声波发射、接收的传导公式,得出由多普勒频移值来获得流量的数学公式;通过分析管道流场速度分布规律,进行了管道横截面平均流速加权修正,完善了多声道多普勒超声波污水流量测量数学模型。本文对多普勒超声波流量测量中的相关理论进行了分析研究。通过MATLAB软件对超声波传播的散射衰减、热传导衰减、粘滞衰减特性进行了仿真,得到介质的密度、动力粘度、超声波的频率及散射颗粒半径等参数与超声波总衰减系数之间的关系,得出超声波散射衰减主要影响散射回波信号的幅值,验证了多普勒法测量的可行性。针对超声波发射频率和传感器的安装位置进行了计算和分析,为了提高运算速度采用了快速傅立叶算法与插值算法这两种频率估计算法。本文详细设计了多声道多普勒超声波污水流量测量方案。硬件设计方面,完成了以DSP为核心的微处理器系统电路、信号反射与接收电路、通道切换与控制电路、系统电源供电等模块设计;软件设计方面,完成了系统监控软件与功能程序设计。最后,针对DFT与FFT算法的运算量进行了比较,通过仿真对算法进行了验证。通过使用插值算法来进一步提高频率的分辨率,基于DSP硬件加速运用FFT算法与插值算法来分析、处理数据,以此加快了数据的处理效率,提高测量结果实时性。本文对系统中信号的发射与接收、带通滤波和混频电路调试,验证了系统设计满足多声道多普勒污水流量测量的要求。
[Abstract]:In recent years, with the rapid development of China's economy, the problem of environmental pollution has become increasingly prominent, especially the problem of water pollution. In order to improve this situation, we can realize the sustainable use of water resources. More accurate real-time monitoring of sewage discharges is needed to assess the environmental level of water use. Based on the theory of ultrasonic Doppler effect, the mathematical model of sewage flow measurement is established, and the transmission formula of ultrasonic emission and receiving is derived. The mathematical formula for obtaining the flow rate from the Doppler frequency shift value is obtained. Based on the analysis of the velocity distribution of the pipeline flow field, the weighted average velocity of the pipeline cross section is modified. The mathematical model of multi-channel ultrasonic ultrasonic sewage flow measurement is improved. The related theory of Doppler ultrasonic flow measurement is analyzed in this paper. The scattering attenuation of ultrasonic wave propagation is analyzed by MATLAB software. Minus. The properties of heat conduction attenuation and viscosity attenuation are simulated, and the relationship between the density, the dynamic viscosity, the frequency of ultrasonic wave and the radius of scattering particles is obtained. It is concluded that the attenuation of ultrasonic scattering mainly affects the amplitude of scattering echo signal, which verifies the feasibility of Doppler measurement. The frequency of ultrasonic emission and the installation position of sensor are calculated and analyzed. In order to improve the operation speed, two frequency estimation algorithms, fast Fourier algorithm and interpolation algorithm, are adopted. In this paper, the multi-channel Doppler ultrasonic sewage flow measurement scheme is designed in detail. The circuit of microprocessor system based on DSP, the circuit of signal reflection and receiving, the circuit of channel switching and control, the power supply of the system and so on are designed. In software design, the system monitoring software and functional programming are completed. Finally, the computation of DFT and FFT algorithm is compared. The algorithm is verified by simulation. By using interpolation algorithm to further improve the frequency resolution, FFT algorithm and interpolation algorithm are used to analyze and process data based on DSP hardware acceleration. In order to speed up the efficiency of data processing, improve the real-time measurement results. The system signal transmission and reception, bandpass filtering and mixing circuit debugging. It is verified that the design of the system can meet the requirements of multi-channel Doppler sewage flow measurement.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X832;TB559

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