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© 2019. This work is licensed under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

Additionally, it is difficult to achieve coverage of the entire XY plane under the ultrasonic focusing field. [...]multiple sets of linear arrayed transducers should operate cooperatively in practice, and the relative positions of multiple sets of transducer arrays should be arranged in a staggered manner according to the focusing patterns of the ultrasonic field. To maintain the maximal output power of the transducer, a reactance is often added in series or parallel at the ultrasonic power output end to ensure that the phase angle is close to zero, and the ultrasonic power load subsequently corresponds to the pure resistance load. [...]the impedance of the vibrator system was initially analysed, and it was necessary to adjust the output frequency of the ultrasonic power supply to the frequency corresponding to the minimum system impedance to improve the coupling process between the ultrasonic power supply and ultrasonic transducer. According to the principle of wave superposition, when multiple ultrasonic beams are superposed on each other with identical or similar frequencies, the vibration amplitude increases in certain areas along the wave propagation direction, while it decreases in other areas, even forming a standing wave. The analysis suggests that differences in the excitation frequency and number of opened transducers led to differences in the distance between the measured node and the centre of the vibration source as well as the wave phase in the measured node. [...]there were differences in the maximum vibration amplitudes in different modes for different frequencies, because the excitation frequency and installation distance of the ultrasonic transducer affected the amplitude superposition effect.

Details

Title
Ultrasonic Guided Wave Phased Array Focusing Technology and Its Application to Defrosting Performance Improvement of Air-Source Heat Pumps
Author
Tan, Haihui; Zhang, Xiaofeng; Zhang, Li; Tangfei Tao; Xu, Guanghua
Publication year
2019
Publication date
Feb 2019
Publisher
MDPI AG
e-ISSN
19961073
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2317014514
Copyright
© 2019. This work is licensed under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.