Research On The Flow Meaurement Of Small Bore Pipe By Acoustics

At present, the acoustic flow measurement mainly used ultrasonic wave as ameasurement tool. The ultrasonic-wave flowmeter has obtained a fast development, howeverthe large energy it consumed and the drawbacks of being unable to continuous measurementas well as the big measurement error in small or medium caliber pipe limit its usage range.This paper proposed a method to precisely measure small caliber pipeline using audioparsing acoustic wave, and made a deep research which can be divided into the followingparts:Firstly, this paper proposed a pipe to prolong the transmission path of acoustic waves,which made full use of the diffraction properties of audio parsing acoustic wave in the spiraltubes.Secondly, this paper conducted a thorough research into the spiral tube. Through theestablishment of spiral tube model with interior space extracted, this paper made a study onthe propagation law of the pipe sound. To lay a basis for further experimental research, weobtained a pipeline Sound Pressure Level (SPL) frequency response curve by simulation,which mainly calculated SPL condition as well as pressure loss versus frequency between thesending point and the receiving point to obtain the minimum pressure value and theappropriate frequency which can reduce noise pollution due to the ultra-high sound pressurein the sending point.The flow noise generated in the pipeline was simulated by the combination of Ansys andLMS Virtual.Lab Acoustics, and the fluid state was analyzed in order to obtain the velocityand pressure distribution of internal fluid. Some measures were taken to enhance the sendingand collecting efficiency, which can reduce the flow noise to make sure that the sound signalcan reached the receiving point at utmost. Therefore, this method can reduce the requirementsof resolution, sensitivity and other parameters in devices.Finally, we established a10mm caliber test platform, and experimented with air toverify the feasibility of the scheme. Because of the limited conditions, we only made aqualitative research on the relationship between the phase difference and flow velocity in twochannels, which showed the reliability of simulation results.As the acoustic flowmeter can overcome the drawbacks of ultrasonic flowmeter, such aslimited caliber, large energy consumption, low measurement precision etc, it wins a broadapplication prospect.