Characteristics of On-Wall In-Tube Thermal Flexible Mass-Flow Sensors

We developed a wall-mounted in-tube thermal flexible sensor for measuring mass flow that can measure the flow rate in both hydraulically developing and fully-developed regions. The flexible structure was achieved by using polymer MEMS technologies. It has high linearity with a TCR of 0.0026K-1, and a steady maximum value for the response time is reached within 7 µ s. The measuring distance from the tube entrance is 8.3D (D = inner diameter of tube). This is much shorter than 64D, the theoretically calculated distance necessary for the formation of a fully-developed flow condition.