Non-Contact Ultrasonic Flow Measurement for Small Pipes Based on AlN Piezoelectric Micromachined Ultrasonic Transducer Arrays

Zhu, Ke; Chen, Xuying; Qu, Mengjiao; Yang, De Ren; Hu, Liang; Xie, Jin

doi:10.1109/jmems.2021.3066408

Cited by 19 publications

(11 citation statements)

References 27 publications

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“…When air bubbles exist in the propagation path, the incident acoustic waves are reflected at the air bubble and fluid interface due to their significant acoustic impedance difference 38 . The acoustic energy passing through the bubble can be neglected because almost all the acoustic energy incident is reflected 20 .…”

Section: Resultsmentioning

confidence: 99%

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

Yuan

et al. 2023

Microsyst Nanoeng

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Ultrasonic fluid bubble detection is important in industrial controls, aerospace systems and clinical medicine because it can prevent fatal mechanical failures and threats to life. However, current ultrasonic technologies for bubble detection are based on conventional bulk PZT-based transducers, which suffer from large size, high power consumption and poor integration with ICs and thus are unable to implement real-time and long-term monitoring in tight physical spaces, such as in extracorporeal membrane oxygenation (ECMO) systems and dialysis machines or hydraulic systems in aircraft. This work highlights the prospect of capacitive micromachined ultrasonic transducers (CMUTs) in the aforementioned application situations based on the mechanism of received voltage variation caused by bubble-induced acoustic energy attenuation. The corresponding theories are established and well validated using finite element simulations. The fluid bubbles inside a pipe with a diameter as small as 8 mm are successfully measured using our fabricated CMUT chips with a resonant frequency of 1.1 MHz. The received voltage variation increases significantly with increasing bubble radii in the range of 0.5–2.5 mm. Further studies show that other factors, such as bubble positions, flow velocities, fluid medium types, pipe thicknesses and diameters, have negligible effects on fluid bubble measurement, demonstrating the feasibility and robustness of the CMUT-based ultrasonic bubble detection technique.

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Section: Resultsmentioning

confidence: 99%

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

Yuan

et al. 2023

Microsyst Nanoeng

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“…Moreover, ScAlN exhibits a larger piezoelectric response than pure AlN films 22 , 23 . Zhu et al reported an ultrasonic flowmeter based on AlN PMUTs with dimensions of 3.2 mm × 3.2 mm 24 , 25 . They successfully realized the flow measurement of paraffin oil with a measuring channel diameter of 8 mm.…”

Section: Introductionmentioning

confidence: 99%

A miniaturized transit-time ultrasonic flowmeter based on ScAlN piezoelectric micromachined ultrasonic transducers for small-diameter applications

Gao

Chen

et al. 2023

Microsyst Nanoeng

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Transit-time ultrasonic flowmeters (TTUFs) are among the most widely used devices for flow measurements. However, traditional TTUFs are usually based on a bulk piezoelectric transducer, which limits their application in small-diameter channels. In this paper, we developed a miniaturized TTUF based on scandium-doped aluminum nitride (ScAlN) piezoelectric micromachined ultrasonic transducers (PMUTs). The proposed TTUF contains two PMUT-based transceivers and a π-type channel. The PMUTs contain 13 × 13 square cells with dimensions of 2.8 × 2.8 mm2. To compensate for the acoustic impedance mismatch with liquid, a layer of polyurethane is added to the surface of the PMUTs as a matching layer. The PMUT-based transceivers show good transmitting sensitivity (with 0.94 MPa/V surface pressure) and receiving sensitivity (1.79 mV/kPa) at a frequency of 1 MHz in water. Moreover, the dimensions of the π-type channel are optimized to achieve a measurement sensitivity of 82 ns/(m/s) and a signal-to-noise ratio (SNR) better than 15 dB. Finally, we integrate the fabricated PMUTs into the TDC-GP30 platform. The experimental results show that the developed TTUF provides a wide range of flow measurements from 2 to 300 L/h in a channel of 4 mm diameter, which is smaller than most reported channels. The accuracy and repeatability of the TTUF are within 0.2% and 1%, respectively. The proposed TTUF shows great application potential in industrial applications such as medical and chemical applications.

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“…transit time [6], cross-correlation [7] and Doppler effect [8]. The Doppler method requires particles in the fluid that can reflect sound waves, while the transit-time method is easily affected by noise interference.…”

Section: Introductionmentioning

confidence: 99%

“…Flight time is usually within the nanosecond range, which may cause low accuracy of measurement. Zhu et al reported ultrasonic flow measurement in an 8 mm diameter pipe based on PMUTs with a relative error of less than 3% [7,17]. Nonetheless, measurement accuracy still needed improvement, and real-time measurement was not feasible because a signal generator and an oscilloscope were used to generate and detect signals.…”

Section: Introductionmentioning

confidence: 99%

A two-channel ultrasonic flowmeter based on AlN piezoelectric micromachined ultrasonic transducers arrays with improved cross-correlation method

Shi,

Qu,

et al. 2023

J. Micromech. Microeng.

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This paper presents a highly accurate two-channel ultrasonic flowmeter based on AlN piezoelectric micromachined ultrasonic transducers (PMUTs) to measure flow rate in small-diameter pipes (9.6 mm). The ultrasonic transducers consist of four 10 by 10 PMUTs arrays with resonant frequency of 1 MHz in air. The ultrasonic transducers are excited by continuous sine voltage, and the transmitted and received signals are subjected to cross-correlation operation to obtain the time delay of the ultrasonic wave in the liquid. A dual-channel design of the flowmeter can reduce measurement errors by taking the average value. To reduce errors in the cross-correlation operation, an iterative algorithm is proposed, which effectively improves the measurement accuracy. The flowmeter is evaluated in flow range of 3.5–10 l min−1, and has a small relative error of 0.7%.

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Non-Contact Ultrasonic Flow Measurement for Small Pipes Based on AlN Piezoelectric Micromachined Ultrasonic Transducer Arrays

Cited by 19 publications

References 27 publications

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

Noninvasive fluid bubble detection based on capacitive micromachined ultrasonic transducers

A miniaturized transit-time ultrasonic flowmeter based on ScAlN piezoelectric micromachined ultrasonic transducers for small-diameter applications

A two-channel ultrasonic flowmeter based on AlN piezoelectric micromachined ultrasonic transducers arrays with improved cross-correlation method

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