This paper firstly proposes an ultrasonic liquid flowmeter based on AlN piezoelectric micromachined ultrasonic transducer arrays. By detecting the transit time of ultrasonic wave, the flowmeter can measure liquid flow in small pipes (8 mm), which is difficult for traditional bulk piezoelectric ultrasonic transducers. In the flowmeter, the acoustic path and flow path are overlapped, which greatly improves sensitivity compared with the typical structure. The cross-correlation method is used to determine the ultrasonic transit time, which can effectively reduce the influence of signal noise and amplitude change. The maximum measurement error of the flowmeter is less than 5% in the flow range of 0–3.36 l min⁻¹.

本文首先提出了一种基于AlN压电微机械超声换能器阵列的超声液体流量计。通过检测超声波的传播时间，该流量计可以测量小管道（8毫米）中的液体流量，这对于传统的体压电超声波换能器来说是困难的。在流量计中，声路和流路是重叠的，与典型结构相比，极大地提高了灵敏度。互相关法用于确定超声传播时间，可以有效减少信号噪声和幅度变化的影响。在0–3.36 l min ^-1的流量范围内，流量计的最大测量误差小于5％。