Flexible ZnO thin film acoustic wave device for gas flow rate measurement

In this work, ZnO/Al thin film based flexible acoustic wave devices are demonstrated for their applications in gas flow rate measurements based on the changes in temperature of the devices. A good sensitivity of gas flow rate can be achieved, mainly because thin film based device has a large temperature coefficient of frequency of similar to 280 ppm K-1, owing to the large coefficient of thermal expansion of aluminum foil. A heat source is used to enhance the sensitivity of the thin film device by introducing a temperature offset. The flexible acoustic wave device shows a high sensitivity, fast response times, and a good repeatability for measurement of the flow rate of nitrogen. When the flexible acoustic wave device is bent and attached onto the inner wall of a pipe, the device exhibits good performance for monitoring the gas flow rate, demonstrating its applications of flow rate measurement on curved or randomly shaped surfaces.

在这项工作中，展示了基于ZnO/Al薄膜的柔性声波器件在基于器件温度变化的气体流速测量中的应用。能够实现良好的气体流速灵敏度，这主要是因为基于薄膜的器件由于铝箔的大热膨胀系数而具有类似于280 ppm K⁻¹的大频率温度系数。通过引入温度偏移，使用热源来提高薄膜器件的灵敏度。该柔性声波器件在氮气流速测量中显示出高灵敏度、快速响应时间和良好的重复性。当柔性声波器件弯曲并附着在管道内壁上时，该器件在监测气体流速方面表现出良好性能，展示了其在弯曲或不规则形状表面上进行流速测量的应用。