Method of measuring sound pressure amplitude in liquid through using acoustic suspension liquid drop

Abstract

A method of measuring a sound pressure amplitude in a liquid through using an acoustic suspension liquid drop is disclosed. The method comprises the following steps of firstly, adding a continuous phase fluid into a transparent rectangular groove body; using a micropipettor to add small and non-soluble liquid drops in the continuous phase fluid; starting an ultrasonic transducer and adjusting output power of a power amplifier so that the liquid drops suspend in the continuous phase fluid; through a high speed camera arranged on a side orientation of a rectangular groove, shooting a picture 1 of tiny liquid drops; then making the high speed camera move horizontally along a focal length direction and shooting a picture 2 of a front panel of the groove body with scales; carrying out image processing analysis on the picture 1 and the picture 2; digitizing a suspension position of the liquid drops under electric power, increasing output power of a power amplifier and successively acquiring the suspension positions of the tiny liquid drops under different electric power; and finally, through a theoretical-formula inverse computation, acquiring sound pressure amplitudes under different ultrasonic electric power. By using the sound pressure amplitude measurement method, problems generated when a hydrophone is used to measure the sound pressure amplitude are solved, accuracy is good and applicability is high.

Description

technical field [0001] The invention relates to a method for measuring the amplitude of sound pressure in liquid by using acoustically suspended liquid droplets, which is used for measuring the amplitude of sound pressure in continuous phase liquid and belongs to the technical field of acoustic measurement. Background technique [0002] Sound pressure parameters are key parameters in many engineering applications and experimental studies, so the measurement of sound pressure parameters has always been the focus of research in acoustic measurement technology. At present, the measurement of the sound pressure amplitude in liquid mainly adopts the sound intensity measuring instrument method and the hydrophone method. The sound intensity value, and then according to the sound intensity I and the sound pressure amplitude P a The conversion relationship between Get the magnitude of the sound pressure amplitude in the liquid. However, due to the large volume of the sound intens...

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Problems solved by technology

The piezoelectric hydrophone method can accurately measure the sound pressure amplitude at low power, but under high power conditions, nonlinear effects such as temperature rise, shock wave, acoustic flow, and acoustic cavitation at the measurement point are likely to cause a decrease in sensor sensitivity , or even damage the hydrophone, and because the hydrophone itself has a certain volume, it will cause certain interference to the sound field distribution in the original continuous phase liquid, and also make the measured value of the sound pressure amplitude inaccurate; the optical fiber hydrophone method It is necessary to place a fiber optic sensor at the measurement site. Since there is often a gap between the fiber sensor and the continuous phase liquid, the gas in the gap acts as a cavitation nucleus, which can easily cause cavitation at the measurement site, resulting in inconsistent measurement results with the actual sound pressure amplitude.

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