Ultrasonic Flowmeter Signal Processing And Realization Technology Research

In the process of the oil production and transmission,the development prospect of Ultrasonic flowmeter is very good, and ultrasonic doppler flowmeter has been widely used in oil fields.Doppler flow measurement can measure flow by detecting the doppler frequency shift creating from ultrasonic transmission in the liquid,which is a kind of methods which is suitable for mixed fluid flow measurement.This method is very applicable to the oil industry because it is non-contact, low cost etc.The residual which coming from identifying tiny doppler offset through traditional spectrum analysis method is too big. This is why the existing ultrasonic flowmeter is restricted on the measurement precision and application range.Because of the deficiency of ultrasonic doppler flowmeter,the doppler signal spectrum analysis method is studied mainly in this article.Ultrasonic flowmeter signal processing method is the main research content of this article. Not only an effective method for extracting signal can extract the doppler frequency shift information of ultrasonic echo signal, but can improve the spectrum resolution of signal. It greatly improves the accuracy of measuring flow which is under the condition of small flow and pipe diameter.In the process of research, accessing for a large number of algorithms on spectrum analysis. In the early stage of the signal processing, analysis the spectrum of signal after analog voltage signal demodulated was converted by TMS320F2812ADC module itself. In order to get a more reliable method, this paper simulates and tests the algorithms using ultrasonic doppler signal created by MATLAB simulation through the fast Fourier transform method, the frequency spectrum refinement method based on wavelet and modulation spectrum analysis etc.By comparing the obtained detailed spectral analysis of complex modulation is more suitable for flow measurement system, and the method in the flow measurement system has been implemented. In order to observing traffic data more convenient during field measurement, liquid crystal display parts and key parts are designed for perfecting the measurement system.A lot of experimental data and theory proves that:modulation selected band spectrum analysis method can achieve higher resolution using fewer sampling points, the computational complexity is relatively small,and easier to implement in engineering.