PYROELECTRIC ANEMOMETRY - FREQUENCY, GEOMETRY AND GAS DEPENDENCE

A series of detailed experiments was conducted on two different types of pyroelectric anemometers: a two-electrode element, 3.8 mm X 3.8 mm X 200 mu m, and a six-electrode element, 7.8 mm X 3.8 mm X 200 mu m. A n a.c. heating current provided a symmetric thermal signal to the elec trodes and the differential response yielded an a.c. signal that depen ds on the flow of gas over the device. The behavior of the amplitude a nd phase of the differential response to frequency, gas composition, a nd geometry was measured. Aside from its value as a mass-flow sensor, the pyroelectric structure is a promising structure for more general s tudies of heat-transfer processes between fluids and solids.