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长春工业大学学士学位论文

摘 要

超声波流量测量技术是一种利用超声波信号在流体中传播时所载流体的流速信息来测量流体流量的新的测量技术。超声波流量计以其非接触、易于安装维护、不会改变流体的流动状态、不产生附加阻力等优点在工业、民用等多领域获得了广泛的应用。超声波流量计作为一种新型仪表，在市场上已经有产品问世，但由于存在一些技术问题，仍没有得到普遍的应用。近几年，传感器技术、先进测量技术、微电子技术的快速发展，为我们进一步研究超声波流量计提供了条件，同时也推动了该仪表的产业化进程。从2004年开始，课题组成员依托吉林省科学技术厅项目“无线温度传感超声波新型热表研制”，开展了无线温度传感超声波新型热表的研制工作，其中超声波流量计的研制是课题研究的重要内容，本论文就是在这种背景下开展的。

目前，基于CPLD和MSP430的无线温度传感超声波新型热表已经研发成功，通过了吉林省电子信息产品监督检验研究所的测试，各项性能指标均达到了合同的要求，并于2008年3月通过了吉林省科技厅科技成果鉴定。

本课题的主要目的是设计并制作超声波流量计，并对相关技术进行研究。主要研究工作包括：首先简要介绍了流量计和超声波流量计的研究意义、发展历史及其研究现状；其次对超声波流速测量方法进行了理论分析，并在此基础上详细介绍了设计中采用的时差法流速测量机理；在第三章中介绍了超声波流量计测量装置的硬件设计，并重点介绍了测量装置的硬件电路以及超声波流量计的工作流程；第四章中分析了超声波流量计设计过程中的关键技术，例如：静水测量水速不为零因素分析、流量计的定标、低功耗设计、回波工作点等，同时给出了这些关键技术的具体解决方法。低功耗设计是超声波流量计设计中一个关键环节，通过采用软、硬件微功耗设计，最终仪表动态工作电流达到了12μA，静态工作电流达到2~3μA，电池寿命10年以上，满足了系统对备用电池的要求；第五章是超声波流量计的实验研究部分，给出了超声波流量计的测试数据，分析了超声波流量计测量误差产生的原因，并提出了提高测量精度的三种方法；最后进行了全文总结。

该超声波流量计具有始动流量小、压损小、功耗低、工作可靠、功能齐全等优点，具有较好的市场应用前景。

关键词：超声波流量计 时差法 CPLD MSP430单片机

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长春工业大学学士学位论文

Abstract

Ultrasonic flow measuring technique which is a new measuring technique, can measure the velocity of flow according to the theory that ultrasonic can carry the information of the liquid when it transits the flowing liquid. Ultrasonic flow meter has many advantages such as: non-contacting, simple fixing and maintaining, not changing the liquid’ flow state, no additional resistance etc. So ultrasonic flow meter it is widely used in industry and civilian measurement. Ultrasonic flow meter is a novel instrument and the products have appeared on the market. However, there are some technical matters of the products. So, ultrasonic flow meter hasn’t been applied widely. In recent years, sensors technique, measuring technique and microelectronic technology are developing rapidly. It provides the condition for further studies on ultrasonic flow meter, at the same time, it speeds up industrialization. From 2004, all the members of the project group support the project of the Office of Science and Technology of Jilin province, which called the development of wireless temperature sensor ultrasonic new-type heat meters. Fabrication of ultrasonic flow meter is the important research content of the project. This paper is started in this context.

At present, the wireless temperature sensor ultrasonic new-type heat meters based on CPLD and MSP430 is developed successfully. It has been passed the measure and test of research institute of quality supervision and inspection of electronic information in Jilin province. Every performance index has reached the requirement of the contract. It has been identified by Science and Technology Bureau of Jilin Province.

The purpose of this project is to design and make an ultrasonic flow meter and study the correlation technique. The main development works are: First, the significance, the development history and the significance of flow meter and Ultrasonic flow meter are briefly introduced; second, theoretical analysis of fluid-velocity measuring methods is carried on, time difference method used in the design is introduced in detail; The hardware design of the measurement equipment of ultrasonic flow meter is introduced in the third chapter, at the same time, the hardware circuit of flow measuring device and the flow of work of ultrasonic flow meter ware introduced on detail; The key techniques of ultrasonic flow meter designing, which involve the calibration method of flow, low-power design, echo operating point, and so on, are analyzed in the forth chapter, simultaneously, the solution is introduced. Low power consumption is the key part during the ultrasonic flow

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长春工业大学学士学位论文

meter designing. The dynamic working current of the equipment drops to 12μA, the quiescent working current can reach 2~3uA and the battery life reached more than 10 years; The fifth chapter is the part of experimental study of ultrasonic flow meter, the test dates are given, the reasons causing measurement error are analyzed, the methods to increase measuring accuracy are put forward; at last, the sixth chapter is the sum-up about the paper.

The ultrasonic flow meter has many advantages such as low starting flow, small pressure loss, low consume, operation reliable, fully functional and so on. It has good potential application of market.

Key Words: Ultrasonic flow meter; Time difference method; CPLD; MSP430;

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长春工业大学学士学位论文

目 录

摘 要 .................................................................................................................... I ABSTRACT .............................................................................................................. II 第一章 绪 论......................................................................................................1

1.1 本课题的来源及研究意义 .........................................................................1 1.2 流量计概述 ..............................................................................................1 1.3 超声波流量计 ........................................................ 错误！未定义书签。 1.4 本文的主要研究内容 ............................................. 错误！未定义书签。 1.5 本章小结 ............................................................... 错误！未定义书签。 第二章 超声波流量计流速测量机理研究 ...............................................................2

2.1 流量的基本概念 .......................................................................................2 2.2 超声波测速方法分类 ................................................................................2 2.3 超声波流量计时差法研究 ...................................... 错误！未定义书签。 2.4 方案对比分析 ........................................................ 错误！未定义书签。 2.5 本章小结 ............................................................... 错误！未定义书签。 第三章 超声波流量计测量装置硬件设计 ............................ 错误！未定义书签。

3.1 CPLD器件的介绍 .................................................... 错误！未定义书签。 3.2 开发环境QUARTUS II及开发语言 ........................... 错误！未定义书签。 3.3 超声波传感器研究 ................................................. 错误！未定义书签。 3.4 超声波流速测量装置硬件电路 ............................... 错误！未定义书签。 3.5 流速测量装置的接口电路及工作过程 ..................... 错误！未定义书签。 3.6 本章小结 ............................................................... 错误！未定义书签。 第四章 超声波流量计关键技术分析 ................... 错误！未定义书签。

4.1 静水测量水速不为零因素分析与解决方案 .............. 错误！未定义书签。 4.2 流量的定标 ........................................................... 错误！未定义书签。 4.3 流量计低功耗设计 ................................................. 错误！未定义书签。 4.4 回波工作点测取与信号接收窗口设置 ..................... 错误！未定义书签。

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长春工业大学学士学位论文

4.5 水流方向与换能器安装的关系 ............................... 错误！未定义书签。 4.6 流速分布修正系数 ................................................. 错误！未定义书签。 4.7 本章小结 ............................................................... 错误！未定义书签。 第五章 超声波流量计的实验研究 ..................................... 错误！未定义书签。

5.1 超声波流量计测试 ................................................. 错误！未定义书签。 5.2 误差原因分析 ........................................................ 错误！未定义书签。 5.3 提高测量精度的方法 ............................................. 错误！未定义书签。 5.4 本章小结 ............................................................... 错误！未定义书签。 结 论 ............................................................................. 错误！未定义书签。 致 谢 ................................................................................................................5 参考文献 ................................................................................................................6 附录1 ....................................................................................................................7 附录2 ....................................................................................................................8 攻读硕士学位期间研究成果 ................................................. 错误！未定义书签。

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