Transverse flowmetry of carbon particles based on photoacoustic Doppler standard deviation using an auto-correlation method  

作　　者：卢涛 孙丽君 

机构地区：[1]College of Electrical Engineering, Henan University of Technology

出　　处：《Optoelectronics Letters》2015年第3期226-228,共3页光电子快报（英文版）

基　　金：supported by the Joint Funds of the National Natural Science Foundation of China(No.U1204612);the Natural Science Foundation of He’nan Educational Committee(No.13A416180)

摘　　要：In order to measure the flow velocity of carbon particle suspension perpendicular to the receiving axis of ultrasound transducer, the standard deviation of photoacoustic Doppler frequency spectrum is used to estimate the bandwidth broadening, and the spectrum standard deviation is calculated by an auto-correlation method. A 532 nm pulsed laser with the repetition rate of 20 Hz is used as a pumping source to generate photoacoustic signal. The photoacoustic signals are detected using a focused PZT ultrasound transducer with the central frequency of 10 MHz. The suspension of carbon particles is driven by a syringe pump. The complex photoacoustic signal is calculated by Hilbert transformation from time domain signal before auto-correlation. The standard deviation of the Doppler bandwidth broadening is calculated by averaging the auto-correlation results of several individual A scans. The feasibility of the proposed method is demonstrated by measuring the spectrum standard deviation of the transversal carbon particle flow from 5.0 mm/s to 8.4 mrn/s. The experimental results show that the auto-correlation result is approximately linearly distributed within the measuring range.

关 键 词：BANDWIDTH Carbon Correlation methods Flow velocity Mathematical transformations Optical pumping Pumping (laser) STATISTICS Time domain analysis Transducers Ultrasonic propagation Ultrasonic scattering Ultrasonic transducers 

分 类 号：TB552[理学—物理] TB937[理学—声学]