Single Sensor Hot-Wire Anemometer Based on Thermal Time Constant Estimation

This paper presents a new type of hot-wire anemometer based on its sensor's thermal time constant estimation. In the known types of thermal anemometers, the source of measurement errors is an ambient temperature, which influences the heat exchange between the hot sensor and its surrounding fluid. Therefore, a second sensor is used to compensate the impact of ambient temperature. The solution contemplated here uses the relationship between the sensor's thermal time constant and fluid flow rate. This constant has no relationship to ambient temperature, so there is no need to use a second sensor. The paper presents algorithms for estimating the sensor's time constant, mathematical relationships, the measurement system and sample measurement results obtained.