The Processing Method of Water Velocity Signal Obtained by Doppler Ultrasonic Velocimeter

Abstract

The invention relates to a processing method of using a Doppler ultrasonic flow meter to obtain water flow velocity signals. The Doppler ultrasonic flow meter comprises a computer, a controller, a receiver and a transmitter, wherein the receiver and the transmitter are respectively connected with the controller; and the computer is connected with the controller. The method comprises the following steps: the Doppler ultrasonic flow meter performs calculation through fast Fourier transform (fft) in a unit time of 20 to 40 milliseconds to obtain a flowing water spectrum graph; in the above flowing water spectrum graph, spectra in a range of f=f0-v / k are selected for analysis, and a flowing water spectrum capture and a spectrum local graph are obtained; weighted average is carried out on frequencies of all points in the above spectrum local graph to obtain the flow velocities of the above flow velocity points; and all the flow velocities are standardized to obtain the flow velocity of a flow velocity point in a measured time. The method can accurately find the flow velocity of the flow velocity point from various interference noise, and a flow velocity value with good stability is finally obtained.

Description

Technical field [0001] The invention relates to a processing method for real-time measurement of fluid flow velocity, in particular to a processing method for obtaining a water velocity signal using a Doppler ultrasonic flow meter. Background technique [0002] When using Doppler ultrasound to measure fluid flow rate, it is necessary to meet the particles of the fluid in front of the emitted ultrasonic signal, and then reflect the ultrasonic signal back to the receiver. After the fluid particles are reflected, the signal transmitted into the receiver is Compared with the transmitted signal, it has changed. According to the Doppler principle, it is necessary to analyze the transmitted signal and the received signal to obtain the velocity of the fluid particles, that is, the flow velocity of the fluid. However, the existing Doppler ultrasonic flow meter calculates the flowing water spectrogram through fast Fourier transform fft within the unit time, and there are about 200,000 data...

AI Technical Summary

Problems solved by technology

However, the existing Doppler ultrasonic current meter calculates the flowing water spectrum through the fast Fourier transform fft within a unit time, and there are about 200,000 data

Use fast Fourier transform (FFT) to analyze the spectrum of the received signal. Due to the small number of particles in the water and the small size of the signal, the received signal will have too much noise, resulting in a poor signal-to-noise ratio.

There is fixed interference in the received signal, and the interference noise near the fixed interference noise is relatively large, so the flow velocity at the flow velocity point cannot be accurately obtained

[0003] At present, there is no signal processing method based on Doppler ultrasound to accurately measure the flow velocity in China. In this scheme, the collected receiving signal is processed by this method to obtain an accurate flow velocity value.

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