Silicon thermal flow sensor with a two-dimensional direction sensitivity

The design and testing of a new type of silicon sensor to measure the magnitude and direction of a fluid flow is described. The measurement principle is based on the detection of flow-induced temperature differences on a hot sensing surface. By measuring temperature differences in two directions perpendicular to each other, a full 360 degrees sensitivity can be obtained. The sensor is made of a silicon IC, on which the flow-induced temperature differences are measured with integrated thermopiles. The use of an IC sensor allows the realisation of a compact multicomponent sensor, which can easily be combined with electronic circuitry. Calibration measurements are presented for air flow.