Estimation of the bubble size distribution by bubble attenuation
Date Issued
2015
Date
2015
Author(s)
Huang, Tz Hau
Abstract
Bubble size distribution is a distribution of particle size and number of different particle size. Each bubble size have different resonant frequency. And the resonant frequency of bubble will make strong scatter signal at that frequency. Estimate the bubble size distribution can help to decide what the frequency of transmit signal will produce strongest scatter signal. In traditional, there are many methods to estimate bubble size distribution, ex: iterative approach and linear double frequency. However, these methods can only estimate the distribution of larger bubble distribution. If want to estimate the distribution of small bubble there will be many limitations. The method we use is to improve the restriction of the estimation small size distribution(1um~10um). In this study, we use the inverse matrix to estimate the bubble size distribution. We assume the distribution follow the Rayleigh distribution. We use frequency sweep to transmit narrowband pulse signal and see the single bubble scatter signal. Then we use bubblesim to calculate scatter cross section, extinction cross section and attenuation. Use the relationship between attenuation and extinction cross section and inverse matrix, SVD method to calculate the bubble size distribution. Finally, we discuss the probe and noise impact and the difficulty of estimating the attenuation of bubble in the real situation. The probe will make the transmit signal weaken except the center frequency. And under the noise effect the transmit signal SNR will become very low. Then let the bubble attenuation loss original curve characteristic. Therefore, we need to adjust these two parameter to let the attenuation curve accord with real situation. Final, explore the accuracy method of use singular value decomposition to estimation bubble distribution.
Subjects
bubble size distribution
bubble attenuation
Type
thesis
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ntu-104-R01945024-1.pdf
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