Experimental Investigation and Uncertainty Analysis of Constant Voltage Anemometer Using Low-Cost Sensor

Abstract

Hot wire anemometer (HWA) is a widely used instrument to perform experimental measurements in laminar, transitional and turbulent flows. A pure, low-cost tungsten filament from an ordinary light bulb is utilized as a hot wire sensor for the analysis of different configurations of constant voltage anemometer (CVA). Experiments are carried out with the proposed sensor for all the three modes of CVA in a self-designed wind tunnel with the laminar flow; the measured velocities are in the mean range of 0.13 m/s to 0.37 m/s. The low-cost sensor is capable of maintaining a constant voltage in spite of the variation in the sensor current caused by fluctuations in the air velocity, in comparison with any commonly used hot wire sensors. Uncertainty analysis is carried out for the proposed low-cost sensor-based CVA measurement system. The maximum standard uncertainty for the output voltage of CVA is less than 0.229 mV for the whole range of measurement. The uncertainty budget is presented along with the estimating procedure. The expanded uncertainties with a 95% confidence level for the basic, compensated and composite CVA are 0.5092, 0.4028 and 0.5148, respectively. This CVA measurement system with an alternative low-cost sensor in a self-designed wind tunnel for laminar flow is a simple, inexpensive and compact model and is proved to be an equitable standby for the CVA Tao systems.