Hot film sensors detect the flow shear stress based on the forced convection heat transfer to the fluid. Current hot film sensors have been significantly hindered by the relatively low sensitivity due to the massive heat conduction to the substrate. This paper describes the design, fabrication, simulation, and testing of a novel flow sensor with dual-layer hot film structures. More specifically, the heat conduction was insulated from the sensing heater to the substrate by controlling both sensing and guarding heaters working at the same temperature, resulting in a higher sensitivity. The experiment and simulation results showed that the sensitivity of the dual-layer hot film sensor was significantly improved in comparison to the single-layer sensor. Additionally, the dual-layer sensor was designed and fabricated in an integrated, flexible, and miniaturized manner. Its small size makes it an excellent candidate for flow detection.

中文翻译：

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基于柔性双层加热结构的高度灵敏流量传感器

热膜传感器基于对流的强制对流传热来检测流动切应力。由于相对于基板的大量热传导，相对较低的灵敏度已严重阻碍了当前的热膜传感器。本文介绍了具有双层热膜结构的新型流量传感器的设计，制造，仿真和测试。更具体地，通过控制在相同温度下工作的感测加热器和防护加热器，将热传导从感测加热器绝缘到基板，从而提高了灵敏度。实验和仿真结果表明，与单层传感器相比，双层热膜传感器的灵敏度明显提高。此外，双层传感器的设计和制造是集成，灵活，和小型化的方式。它的小尺寸使其非常适合进行流量检测。