Development Of Seepage Acoustic Measuring Device And Experimental Study On Bubble-water Acoustic Properties

Bubble-water medium acoustic properties research of the seafloor seepage has important significance in the field of economic construction and ecological protection. The main acoustic physical parameters of cold seepage research include:velocity, sound attenuation and bubble velocity. The study of the seafloor seepage bubble sound characteristics is using the methods of measuring echo ultrasound. Due to the flow state of bubble is unstable under the open environment. Reverse echo not only experienced the attenuation of seawater, but also suffered forward and inverse scattering of the random bubbles. Echo signal is an unstable signal, causing the measurement accuracy difficult to ensure. So, in order to meet the acoustic properties of the seafloor seepage bubbles, based on the research of our group, the paper has simulated seabed seep and developed seafloor seepage acoustic measuring device which the bubble breakup with uniform device is the preprocessing module, rectangular transducer is the sensor, bubble flow is measured with the transmission-acoustic wave amplitude.The current research situation of seafloor seepage bubble measurement was introduced, including non acoustic measurement and acoustic measurement, the main acoustic properties of seafloor seepage bubble was summarized. Moreover the calculation method of the bubble-water sound velocity, sound attenuation and bubble velocity were analyzed based on the experimental measurement principle.The paper expounded the general design of seafloor seepage acoustic measuring device and the two parts of structure design:bubble collecting and preprocessing device with the sensor measuring device. Bubble collecting and preprocessing device mainly introduced the bubble breakup grid and bubble breaking-uniform device, and its structure and working principle were introduced in this paper. Sensor measuring device mainly introduced the transmitting transducer module and rectangular transducer. The key part of the measuring device-wave divider has carried out on the detailed design and experimental verification, by the air and water experiments demonstrated the validity of the design. The propagation time of measurement system was obtained by coupling contact between transmitting transducer and receiving transducer module. Based on the acoustic properties measurement system, the seafloor seepage bubble-acoustic characteristics measurement experiment was carried out using1MHz rectangular transducer to be sensors. Analyzed the sound wave signals which wave collected by the measurement system, mainly included bubble-water sound velocity, sound attenuation and bubble velocity. Study the changes in acoustic parameters for different void fraction of volume. Study on the effect of different water depth on the measured results. Comparative analyzed the changes of bubble-water medium sound velocity, attenuation and bubble velocity under different water depth.The improving advices about the measurement of seafloor seepage bubble-acoustic characteristics were presented in the paper, combined with the problems of the debugging and experiment measurement.