高精度超声波流量计的研发

发布时间：2018-07-31 05:37

【摘要】：超声波流量计,它是一种在超声波测量相关理论的基础上,通过对流体在管道内流动时的速度进行测量,经过相关信号处理和数据计算,进一步测得管道内流体流量的仪器,它关系到我们的日常生活各个方面。20世纪以来,新的信号处理技术不断涌现,硬件电路单元也变的更加密集化,伴随着越来越多的新型超声换能器的出现,进一步提升了整个超声波流量检测领域的设计和加工水平。产品设计费用低廉,应用领域广泛、易于安装和使用等都是超声波流量计的一些特点,因此在石油开采、天然气勘探、航空制造、生物医疗等领域有着大量应用。流量计是工业发展不可缺少的工具,对于现代工业生产的需求来说,安装简单、更高精度和更加智能化的超声波流量计的设计是非常必要的。本文基于超声波时差法测量流体流速的方法,结合以ARM芯片为核心的嵌入式硬件平台,设计出了新型的具有较高精度的超声波流量计,之后进行了相关流量测量的模拟实验,对本文设计的超声波流量计的检测效果进行了验证。首先对超声波流量计的产生背景,以及近几年国内外超声波流量计的应用现状进行了分析,然后将超声波流量计的流量检测原理进行了阐述和对比,最后选择时差法作为本次设计的核心方法。其次因为超声波自身的衰减特性和周围环境的噪声干扰等的影响,导致检测到的超声波信号能量较弱并且波形相对杂乱,需要经过相关的信号调理模块处理之后才能进一步分析。然后通过设计相应的信号采集模块,以ARM微控制器芯片为核心,将信号采集处理后,通过以太网口的传送方式将数据发送给计算机进行后期数据处理。最后在计算机上针对采集到的超声波信号的特点,使用MATLAB软件,结合经验模态分析(Empirical Mode Decomposition),希尔伯特黄变换(Hilbert-Huang Transform)等信号检测领域的分析方法对信号进行了后期处理,使测量结果更为准确,并在此基础上设计了基于LabWindows/CVI的超声波流量计的测量系统。通过搭建相关实验平台,对模拟管道内流体流动的实验采集到的数据进行分析验证后,可以较为准确的得到流体流量,证明该超声波流量计的测量效果良好。
[Abstract]:Ultrasonic Flowmeter, based on the theory of ultrasonic measurement, is an instrument to measure the flow rate of the fluid in the pipeline by measuring the velocity of the fluid flowing in the pipeline, and through the related signal processing and data calculation. It is related to every aspect of our daily life. Since the 20th century, new signal processing technology has been emerging, and the hardware circuit unit has become more and more dense, along with the emergence of more and more new ultrasonic transducers. Further improve the design and processing level of the whole ultrasonic flow detection field. The low cost of product design, wide application, easy installation and use of ultrasonic Flowmeter are some characteristics of ultrasonic Flowmeter, so it has a large number of applications in the fields of petroleum exploitation, natural gas exploration, aviation manufacturing, biomedicine and so on. Flowmeter is an indispensable tool for industrial development. For the demand of modern industrial production, the design of ultrasonic Flowmeter with simple installation, higher precision and more intelligence is very necessary. In this paper, a new ultrasonic Flowmeter with high precision is designed based on the ultrasonic time difference method and the embedded hardware platform based on ARM chip. The effect of ultrasonic Flowmeter designed in this paper is verified. Firstly, the background of ultrasonic Flowmeter and the application status of ultrasonic Flowmeter at home and abroad in recent years are analyzed, and then the flow detection principle of Ultrasonic Flowmeter is expounded and compared. Finally, the moveout method is chosen as the core method of this design. Secondly, because of the attenuation characteristics of ultrasonic wave and the noise interference in the surrounding environment, the detected ultrasonic signal is weak in energy and relatively chaotic in waveform. It needs to be processed by relevant signal conditioning module before further analysis. Then through the design of the corresponding signal acquisition module, taking the ARM microcontroller chip as the core, after the signal acquisition and processing, the data is sent to the computer for later data processing through the transmission mode of the Ethernet port. Finally, according to the characteristics of the collected ultrasonic signal on the computer, using MATLAB software, combined with empirical modal analysis of (Empirical Mode Decomposition), Hilbert-Huang transform (Hilbert-Huang Transform) signal detection and other signal detection methods for the post-processing of the signal. The measurement system of ultrasonic Flowmeter based on LabWindows/CVI is designed. By setting up the relevant experimental platform and analyzing and verifying the data collected in the experiment of simulating the fluid flow in the pipeline, the fluid flow rate can be obtained more accurately, which proves that the ultrasonic Flowmeter has a good measuring effect.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH814.92

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