论文总字数：18679字

摘 要

电容式两相流流量计系统是一个非常复杂的系统，动态变化而且非线性。但在工业设备领域应用前景极其广阔。气/固两相流动过程表现出不稳定，而且相当复杂。所以给信号的检测带来不小的困难。通常情况煤炉整个系统运行状态并不理想。因此煤粉在高温的锅炉里没有办法实现最佳的燃烧状态。管道煤粉的浓度以及管道中煤粉的流动速度这两个因素大大影响到了煤粉喷射到炉内的煤粉体积与气体体积的比例进而影响到管道中煤粉燃烧起来效率跟状况。本文从工业应用角度出发，设计了一种双层电容式螺旋电极气/固两相流流量计，通过电容传感器测定相浓度，双层传感器作一定的运算测出煤粉流动的速度，从而实现管道中煤粉流量的检测。本课题的主要研究内容如下：

1.设计高精度的电容检测电路:该电路的设计要求有抗干扰的能力，改善整个测量系统的稳定性。研制出高精度的双路微弱电容检测电路，来解决传感器灵敏度差而引起传感器输出电容信号弱的问题。该流量计测量系统的采用了两路信号采集电路，两路信号通过的时间作差，便得到他们通过的时间间隔，从而实现煤粉的流速检测。检测电路中增加了激励信号的幅度并引入带通滤波，对前级运算放大器和交流放大引入的噪声进行滤波，为了改善电容检测的精确度，本设计在放大级前加入了一个带通滤波器。它可以有效的消除因为放大器本身的一些因素而引进的噪声信号。

2.设计合适的电容数据采集和数据处理系统，用于测量系统的控制和采集数据的处理，包括相关计算和相浓度提取等。21世纪电子信息产业技术的飞猛提高，芯片设计制造工艺也越来越发达，比如ARM公司。ARM芯片应用越来越广泛。不光可以应用在工业控制方面还可以应用在信号采集与处理方面。本设计采用比较常见且价格低廉的STM32F103 RC为控制器作为设计为核心，它能够大批量处理数据，同时也具备实时管理功能。对于A/D转换器的使用方面，设计中我们采用了AD7606，它由亚德诺半导体公司生产的。16位高精度的模数转换器。这样就可以实现数据的高速采集了。

关键词：两相流 电容传感器 数字信号处理器 信号检测

Abstract

The two phase flow system is a complex nonlinear dynamic system, which is widely existed in the industrial process. Gas / solid two-phase flow process complexity and randomicity of the result in the parameter detection is very difficult in general, whole blowing system is difficult to maintain run in reasonable condition, so coal in the high temperature furnace and the optimum combustion can not be achieved. The concentration of pulverized coal and the flow rate of the pulverized coal in the pipeline greatly affect the pulverized coal injection into the furnace and then affect the combustion efficiency and the status of the pulverized coal in the pipeline. This article from the perspective of industrial application of designed a double-layer capacitance spiral electrode gas / solid two-phase flow flowmeter and concentration was determined by the capacitance sensor, double sensor for correlation algorithm is used to measure the velocity of solid phase, so as to realize the measurement of solid flow. The main research contents of this paper are as follows:

1. the design of high precision capacitance detection circuit: the requirements of the circuit has the ability to resist stray capacitance, to improve the reliability of the detection circuit system. To solve the problem of low sensitivity of the sensor and the weak signal of output capacitance of the sensor, the high precision of the weak capacitance detection circuit is developed. The capacitance detection circuit uses a dual channel, two channel signals are calculated to obtain the time difference of the fluid flow through the two sensor, so as to realize the measurement of two-phase flow velocity. Detection circuit increases the amplitude of the excitation signal and band pass filter is adopted. The front stage operational amplifier and AC amplification introduced noise filtering, pre amplifiers of the precision of the capacitance signal detection accuracy is critical, introducing bandpass filter can eliminate the sine wave bandwidth noise effects to improve the detection signal to noise ratio of the system.

2 design suitable capacitance data acquisition and data processing system, which is used to measure the control of the system and collect the data, including related calculation and phase concentration extraction. With the rapid development of electronic information products, chip design and manufacturing technology is also becoming more and more advanced, such as ARM company. ARM chip application is more and more extensive. Not only can be used in industrial

control can also be used in the signal acquisition and processing. This design uses the sense of the semiconductor company's chip STM32F103 series of SCM as the core of the design, it can deal with data in large quantities, but also has the function of real-time management. According to the high precision analog-to-digital converter design, we use AD7606, which is composed of analog semiconductor company. 16 bit high precision analog to digital converter. This can achieve high-speed data acquisition.

Key words: two phase flow;Capacitance sensor;Digital signal processor;signal detection

目录

摘要 I

Abstract II

目录 IV

第一章 绪论 1

1.1课题背景 1

1.2课题的目的和意义 2

1.3课题的内容和所要解决的问题 2

第二章 流量计的测量原理 3

2.1相浓度的测量 3

2.2速度的测量 4

第三章电容检测和数据测量 5

3.1信号发生器的同步 6

3.2电流电压转换电路 7

3.3 C/V 转换电路 8

3.4放大电路 9

3.5带通滤波 10

3.6乘法器 11

3.7低通滤波器 12

3.8电源模块 13

3.9A/D模数转换 15

3.10JTAG/SWD接口 16

3.11主控制MCU 16

第四章 系统软件设计 18

4.1 开发软件简介 18

4.2系统程序初始化 18

4.3 信号发生器软件设计 19

4.4 AD7606数据采集模块软件设计 20

参考文献 23

致谢 24

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