外文翻譯---脈沖輸出型數(shù)字渦街流量計(jì)的研究

1、.附錄AResearch on pulse output model digital vortex flow metersThe vortex flow meter is widely used in different fields due to its flexibility to various media, non-mobile parts, simple structure and long life etc. However, it has poor performance when operating at low flow rate where the Signal-to-No

2、ise ratio is very small or even the signal is submerged by the noise. The traditional analog vortex flow meter has benefits of steady signal, high accuracy and good real time in the regular flow range, while it also has a disadvantage of weak signal difficult to detect at low flow rate, which leads

3、to unsatisfying lower limit and a smaller range ratio of 10:1.Based on the previous efforts a pulse output model digital vortex flow meter is developed successfully, which inherits the advantages of the analog one and make up its shortage mentioned above. The digital vortex flow meter with its doubl

4、e-core structure that means a couple of CPUs made up of DSP and MSP430 identifies the vortex signals from noises by the frequency spectrum analyzing algorithm in DSP at low flow rate where the analog one is not accurate, or even cant work. Meanwhile it works out by its microcontroller MSP430 the fre

5、quency of the vortex signal that is square waves output from pre-amplifier for the vortex signals in the regular flow range where the Signal-to-Noise ratio isnt too much small and the analog one is accurate and real time.This dissertation consists of theory, hardware/software design and experiment.

6、The main point includes:1.The scheme called double-channel work model of the pulse output model digital vortex flow meter is designed. The principle is a switch of two different methods to detect the vortex signal. That is using spectrum analysis of digital signal at low flow rate and frequency coun

7、ting like analog vortex flow meters in the regular flow range. The critical criterion of the switch point is the uncertainty of the frequency.2.A pulse output model digital vortex flow meter is developed successfully. The flow meter is studied respectively at DN25 and DN50 pipelines of the water flo

8、w experiment facility and DN50 and DN100 pipelines of the gas flow experiment facility that locate at Process Detect & Control Laboratory in Tianjin University. And the data shows that the digital flow meter has the property of a better lower limit than the analog one and a bigger range ratio of

9、 1:28.541.3. Masses of experiments on the digital vortex flow meter have been carried out at the water flow experiment facility and the gas flow experiment facility of Tianjin University respectively. The result shows that the pulse output model digital vortex flow meter has a satisfying lower limit

10、 that increases the range ratio effectively, strong ability and good real time and thus it is of great practicability.The 21st century is the century information, information and materials and new technology as the main pillar of society from the human revolution is industrialization era to informat

11、ion era, as the perception, acquisition, conversion, processing and transmission of information technology and the indispensable testing instrument, has become an important technology and computer equivalent and daily life and production of all fields. Along with the rapid development of science and

12、 technology, industrial production get continuous development, the detection technology and puts forward many new requirements, and new technology and instrument appearance and further promote the development of science and technology, the development degree of detecting technology has decided to sc

13、ience and technology level, in other words detection techniques and instruments is the measure of modern science and technology level of a mark. This one, as testing technology is an important part of flow metering with national economic and national defense, science and technology, the close relati

14、onship in economic development plays an important position.After continuous efforts, and technical workers have developed pyretic and various characteristics of flow meter. According to the measuring method and the structure of the classification method, will be divided into differential pressure me

15、ter flowmeter, volumetric flowmeter, fluid flow, ultrasonic vibration flowmeter, mass flowmeter, insert flowmeter open-channel flow and other flowmeter, 11 kinds . The research of the vortex flowmeter belongs to the hydrodynamic vibration flowmeter are widely used .Vortex flowmeter is according to t

16、he fluid velocity of vibration frequency and the corresponding principle of work. As early as in 1878 straw Strophe published about fluid velocity relationship with the vibration frequency, straw, vortex frequency is said to stop features of similar size and the velocity of the relationship. People

17、in the early vortex research mainly is the purpose of prevention. Vortex flow vibration phenomenon for measuring the study began in the 1950s, such as wind meter and ship speed gauge etc, at the end of the 1960s began to develop close pipeline flow - vortex flowmeter. 1970s and 1980s vortex flowmete

18、r unusually quick development, development outstanding type resistance fluid and detection methods of vortex flowmeter, and mass production, such as the market in just a few short years time to arrive from laboratory batch production process of the sample flow is unique.Vortex flowmeter is a fluid v

19、ibration flowmeter, set in the fluid flow vortex happened (resistance from vortex happen) alternately on both sides of the body produces regular vortex, the spiral called Carmen vortex, swirling in spiral happen asymmetrical body downstream, vortex flowmeter is arranged by measuring the vortex frequ

20、ency and realization of flow measurement.Vortex flowmeter by sensors and switches two parts. Sensors (including vortex flow resistance occurs, components, instrument) such as table, converter including pre-amplifier, filtering plastic circuit, D/A transformation circuit, output interface circuit, te

21、rminals, bracket and shields, etc. In recent years, intelligent flowmeter is the microprocessor, communications and other functions that are installed in converter module.According to the detection means, vortex flowmeter stress can be divided, capacitive and thermal type, type of ultrasonic vibrati

22、on, strain, and photoelectric and fiber, etc. Among them, stress (also called the piezoelectric) vortex flowmeter with its fast response and strong signal, working temperature range wide, strong adaptability and high reliability etc, has become the main products vortex flowmeter type. This vortex fl

23、owmeter, it is to test the lift in form stress testing devices, piezoelectric conversion variable charge signal, clinch a deal the charge amplifier, filtering, plastic after vortex signal. Piezoelectric sensor signals, fast response and low cost, manufacturing process, but is more sensitive to vibra

24、tion.As mentioned, vortex flowmeter has many advantages, and there are many problems to be solved, especially in the measurement of small flow, vortex useful signal is very weak, yi was drowned, low noise signal under the velocity measurement caused great difficulties. In order to solve this problem

25、, the domestic and overseas scholars and scientific research institutions in research and application of various solutions, namely of digital signal processing method to solve, but most just stay in the research on the method of high efficiency, and not be applied algorithm support for production. A

26、t present, the domestic production of the vortex flowmeter is limited to the analog circuit application method of vortex signal processing (called simulation vortex flowmeter), this can not solve the low SNR, leading to lower the problem than only achieve high, range 1:1 scale theory, far below zero

27、. Foreign company, Yokogawa only Rosemount and ABB has developed the application of digital signal processing methods of signal processing vortex, namely digital vortex flowmeter, but specific technology is not open.In recent years, the vortex signal processing methods about the study many (such as

28、wavelet method of adaptive LMS changes, etc), the algorithm of tianjin university professor zhang tao presided over the research of vortex sensor output signal for exploration of digital signal processing won great progress. Ling Qing master according to the signal features and vortex of signal proc

29、essing method, the requirements for maximum likelihood estimation results in cycle chart are put forward on the basis of more suitable for relaxation of the vortex frequency estimation method of graph, commit cycle and the simulation experiments. This method with high resolution and high frequency c

30、haracteristics of the calculation efficiency, strong resistance to complex noise interference ability. WuPeng master based on wavelet transform, deposing principle of flow measurement specific requirements, and puts forward a suitable vortex flow sensor signal processing methods of single reconstruc

31、tion filter is given, and the method of selecting, filter series of this method can effectively expand vortex flow sensor range. However, due to the above two methods, the complexity of algorithm, real-time computation is not guaranteed, and applied in practice.Along with the Digital Signal Processo

32、r Digital Signal processing (DSP) technology, referred to the rapid development and wide application, make complex Signal processing algorithm can achieve in hardware. DuanRuiFeng master a set of DSP and MSP430 microcontroller combination of the vortex digital signal processing system, using slack t

33、rapped cycle graph method for calculating the vortex flowmeter signal frequency. Experimental results show that the vortex flow dual-core digital signal processing system can effectively reduce the measurement limit (mm diameter measurement can reach vortex lower 0.323 m3 / h), realize the real-time

34、 data processing.This topic is on the basis of research achievements in domestic production, the vortex flowmeter is limited to simulate the vortex flowmeter, research and implementation of a practical pulse output type vortex flowmeter figures. The pulse output type digital vortex flowmeter using M

35、SP430 MCU based on DSP and the twin CPU hardware structure, small flow in low velocity by DSP based on fast Fourier transform (FFT) form fast, referred to as the power spectrum estimation is proposed to measure vortex frequency real-time pulse output, When the flow in the normal flow range analogue

36、circuit, signal preprocessing vortex, then by microcontroller program flow calculations, display, frequency, pulse output etc. The digital pulse output type vortex flowmeter in tianjin university experiment device and gas flow flux on doing a lot of experiments, the results show that the instrument

37、effectively expand the scale of the vortex, lower than the measuring low, repeatability, strong anti-jamming ability, good real-time, etc.附錄B脈沖輸出型數(shù)字渦街流量計(jì)的研究渦街流量計(jì)因其介質(zhì)適應(yīng)性強(qiáng)，無(wú)可動(dòng)部件，結(jié)構(gòu)簡(jiǎn)單、使用壽命長(zhǎng)等諸多優(yōu)點(diǎn)，在許多行業(yè)得到了廣泛的應(yīng)用。而在低流速下，渦街測(cè)量就顯現(xiàn)出了它的不足，渦街信號(hào)的信噪比很低，有用信號(hào)幾乎被噪聲淹沒(méi)。普通的渦街流量計(jì)采用模擬信號(hào)處理方法，在正常流量范圍內(nèi)，渦街流量信號(hào)穩(wěn)定、測(cè)量準(zhǔn)確、實(shí)時(shí)性好；而在小

38、流量下，渦街有用信號(hào)微弱、提取困難，導(dǎo)致實(shí)際測(cè)量下限比較高，量程比小，一般為10：1。鑒于上述模擬渦街流量計(jì)具有的優(yōu)勢(shì)以及存在的不足，課題在前人研究成果的基礎(chǔ)上，研究并成功地實(shí)現(xiàn)了一臺(tái)實(shí)用的脈沖輸出型數(shù)字渦街流量計(jì)。該數(shù)字渦街流量計(jì)采用了基于DSP和MSP430單片機(jī)雙CPU的硬件結(jié)構(gòu)，在低流速小流量的情況下，由DSP實(shí)現(xiàn)頻譜分析算法來(lái)計(jì)算渦街信號(hào)頻率，有效地克服了模擬渦街在小流量下測(cè)量精度不高甚至不能測(cè)量的問(wèn)題；在正常流量范圍內(nèi)，由單片機(jī)對(duì)渦街信號(hào)前置放大電路輸出的方波進(jìn)行計(jì)頻，具有常規(guī)模擬渦街在高信噪比的情況下測(cè)量準(zhǔn)確、實(shí)時(shí)性好的優(yōu)點(diǎn)。本文從原理分析、硬件軟件設(shè)計(jì)和實(shí)驗(yàn)研究三方面來(lái)研究，主

39、要內(nèi)容包括：1.設(shè)計(jì)了脈沖輸出型數(shù)字渦街流量計(jì)的總體方案，尤其是采用了雙通道處理的方式，將低流量下數(shù)字信號(hào)處理的頻譜分析功能和正常流量范圍內(nèi)智能渦街的計(jì)頻功能有機(jī)地結(jié)合起來(lái)，并引入了頻率不確定度的概念作為判斷渦街有用信號(hào)雙通道處理方法的依據(jù)。2.成功實(shí)現(xiàn)了一臺(tái)脈沖輸出型數(shù)字渦街流量計(jì)。通過(guò)在天津大學(xué)過(guò)程檢測(cè)和控制實(shí)驗(yàn)室的水流量實(shí)驗(yàn)裝置上進(jìn)行的25mm口徑和50mm口徑實(shí)驗(yàn)研究，以及在氣體實(shí)驗(yàn)裝置上進(jìn)行的100mm和50mm口徑實(shí)驗(yàn)研究的結(jié)果表明，本脈沖輸出型數(shù)字渦街流量計(jì)有效地降低了渦街的流量下限，使量程比顯著擴(kuò)大，量程比達(dá)到1：28.541.3。將此數(shù)字渦街分別在天津大學(xué)水流量實(shí)驗(yàn)裝置和氣體

40、流量實(shí)驗(yàn)裝置上做了量的實(shí)驗(yàn)，結(jié)果表明本脈沖輸出型數(shù)字渦街流量計(jì)具有很低的測(cè)量下限，有效擴(kuò)大了渦街的量程比，抗干擾能力強(qiáng)，實(shí)時(shí)性好，具有很高的實(shí)用價(jià)值。21世紀(jì)是信息的世紀(jì)，以信息、材料和生物為主要支柱的新技術(shù)革命正將人類社會(huì)從工業(yè)化時(shí)代推向信息化時(shí)代，作為感知、采集、轉(zhuǎn)換、處理和傳輸各種信息不可缺少的檢測(cè)技術(shù)和儀表，已成為與計(jì)算機(jī)同等重要的技術(shù)而深入日常生活及生產(chǎn)的所有領(lǐng)域。隨著科學(xué)技術(shù)的突飛猛進(jìn)，工業(yè)生產(chǎn)得到不斷發(fā)展，對(duì)檢測(cè)技術(shù)又提出了許多新的要求，而新的檢測(cè)技術(shù)和儀表的出現(xiàn)又進(jìn)一步推動(dòng)了科學(xué)技術(shù)的發(fā)展，故檢測(cè)技術(shù)的發(fā)展程度決定了科學(xué)技術(shù)的水平，換句話說(shuō)檢測(cè)技術(shù)和儀表是衡量現(xiàn)代科學(xué)技術(shù)水平高

41、低的一個(gè)標(biāo)志。這其中，作為檢測(cè)技術(shù)重要組成部分的流量計(jì)量由于與國(guó)民經(jīng)濟(jì)、國(guó)防建設(shè)、科學(xué)技術(shù)的密切關(guān)系，在經(jīng)濟(jì)發(fā)展中占有重要的地位。經(jīng)過(guò)不斷的努力和探索，科技工作者已開(kāi)發(fā)出種類繁多、各具特色的流量?jī)x表。按照測(cè)量方法和結(jié)構(gòu)的分類方法，將流量計(jì)分成差壓式流量計(jì)、容積式流量計(jì)、流體振動(dòng)式流量計(jì)、超聲流量計(jì)、質(zhì)量流量計(jì)、插入式流量計(jì)、明渠流量計(jì)和其他流量計(jì)共十一大類。本課題研究的渦街流量計(jì)屬于流體振動(dòng)式流量計(jì)中應(yīng)用最為廣泛的一種。渦街流量計(jì)是依據(jù)流體振動(dòng)頻率與流速有對(duì)應(yīng)關(guān)系的原理進(jìn)行工作的。早在1878年斯特勞哈（Strophe）就發(fā)表了關(guān)于流體振動(dòng)頻率與流速關(guān)系的文章，斯特勞哈數(shù)就是表示渦街頻率與阻擋

42、體特征尺寸、流速關(guān)系的相似準(zhǔn)則。人們?cè)缙趯?duì)渦街的研究主要是防災(zāi)的目的。渦街流體振動(dòng)現(xiàn)象用于測(cè)量研究始于20世紀(jì)50年代，如風(fēng)速計(jì)和船速計(jì)等，60年代末開(kāi)始研制封閉管道流量計(jì)渦街流量計(jì)。70、80年代渦街流量計(jì)發(fā)展異常迅速，開(kāi)發(fā)出眾多類型阻流體及檢測(cè)方法的渦街流量計(jì)，并大量生產(chǎn)投放市場(chǎng)，像這樣在短短幾年時(shí)間內(nèi)就到達(dá)從實(shí)驗(yàn)室樣機(jī)到批量生產(chǎn)過(guò)程的流量計(jì)還絕無(wú)僅有。渦街流量計(jì)是一種流體振動(dòng)式流量計(jì)，在流體中設(shè)置旋渦發(fā)生體（阻流體），從旋渦發(fā)生體兩側(cè)交替地產(chǎn)生有規(guī)律的旋渦，這種旋渦稱為卡門渦街，旋渦列在旋渦發(fā)生體下游非對(duì)稱地排列，渦街流量計(jì)通過(guò)測(cè)量其旋渦產(chǎn)生的頻率而實(shí)現(xiàn)流量計(jì)量。渦街流量計(jì)由傳感器和轉(zhuǎn)換器兩部分組成。傳感器包括旋渦發(fā)生體（阻流體）、檢測(cè)元件、儀表體等；轉(zhuǎn)換器包括前置放大器、濾波整形電路、D/A轉(zhuǎn)換電路、輸出接口電路、端子、支架和防護(hù)罩等。近年來(lái)智能式流量計(jì)還把微處理器、顯示通訊及其他功能模塊亦裝在轉(zhuǎn)換器內(nèi)。按檢測(cè)方式劃分，渦街流量計(jì)可分為應(yīng)力式、電容式、熱敏式、超聲式、振動(dòng)式、應(yīng)變