Simulation and fabrication of a 2D-flow sensor for thermal characterization of fluids and for flow speed measurements

An enhanced flow sensor is under development at IMTEK to enable simultaneous measurement of thermal properties of a fluid and its flow velocity. Simultaneous measurement of these properties is necessary to measure flow rates accurately by thermal means in cases where fluid properties fluctuate in time. Here, we report the design and the fabrication of our flow sensor and present the influence of fluid thermal conductivity on the measurement signals. We further discuss the possibilities of decoupling fluid thermal properties and flow velocity using time-dependent heating. Simulation results suggest that phase shift on a side thermistor location depends more on thermal conductivity than the other thermal properties. Therefore, it can be a key parameter in the measurement of thermal conductivity in the presence of a flow.