Bubble Pretreatment And Signal Source Researchs In Submarine Gas Leakage Acoustic Measurement

The foreign use acoustic method for measuring seafloor gas seepage flow, mainly by reflection wave, this method is suitable for high flow rates, for small gas flow situation we need to adopt the transmitted wave measurement. Our research group proposed by study of bubble state before adjustment by wave waveform-amplitude parameter measurement leakage of bubble flow, and carried out simulation experiments of bubble flow ultrasonic detection.The preliminary test and study confirmed the validity of the proposed, but still lack some basic research necessary for inversion of bubble flow, such as bubble flow parameters and the transmission of ultrasonic frequency, sound intensity, the relationship between the parameters of. To get accurate results of measurement of bubble flow needs to adjust the bubble flow size and spatial distribution, and then perform the measurement, so the first need to design air pretreatment device. In addition, when using acoustic method for gas flow measurement process, the acoustic signal source needs to be able to output two basic wave, sine wave and pulse wave, in addition to having frequency wave and pulse train output function.The general signal source can not meet the requirements, need to design new acoustic signal source, for in situ measurement of seafloor gas seepage flow.This paper completes the design of device bubble Pretreatment Based on the previous basis, bubble pretreatment device designed by the multilayer overlapped, the internal structure of bubble pretreatment device to complete the motion bubble breakup and uniform distribution.Each layer of the bubble pretreatment device is divided into a bubble on the cutting, diversion, under the guide of three parts.The cutting part is used to realize the bubble bubble collision crushing; diversion part played the role of bubble bubble collecting, makes the correct direction of motion on the guide part; for the correction of bubbly flow path so that it is evenly covered with a layer of diversion of space.In addition, the design of the pretreatment experiment system for submarine leakage bubbles, including the seabed leakage bubble simulation device, bubble breaking experiment device and a digital image acquisition device three modules. And experiment was carried out in the experimental system after the data, after the analysis of these data processing by using MATLAB relevant conclusions.Finally gets the conclusion of bubble pretreatment device designed on bubble diameter, velocity and volumetric gas content and other parameters, it is also proved that the bubble pretreatment device effectively complete the bubble breakup and uniform treatment.in addition, the acoustic signal source design basic wave, frequency hopping wave and pulse train output function, the output waveform accuracy and stability meet the requirements.In this paper, through the experimental method to study the pretreatment of bubbles, bubble pretreatment device designed to meet the requirements of the final.The design of acoustic signal source is stable, can be used for acoustic transmission measurements of the sea floor leakage gas flow.