Experimental Study of Temperature, Pressure, Humidity, And/Or Density Effects on Vane Anemometers

Experimental investigations of velocity measurements were performed on three vane anemometers in steady variable-density flows. Measurements of velocity variations as a function of flow temperature, pressure, and humidity have been collected by an electronic vane anemometer (EVA), a rotating vane anemometer (RVA), and a deflecting vane anemometer (DVA). The study aimed at measuring the effects of density changes on velocity measurements taken by the three anemometers and determining how well the available theoretical models correspond to the corrections produced by experimental data. The results indicate significant effects of temperature and pressure on the velocity measurements acquired by the three anemometers. In general, the humidity effects are small and therefore are of minor influence on the response of all vane anemometers. The collected data were compared with the theoretical predictions addressed in the first phase of ASHRAE Research Project RP-698. For the propeller and revolving vane anemometers (EVA and RVA), the theoretical and experimental corrections are in close agreement. However, the experimental measurements indicate that the DVA experimental corrections deviate considerably from the corresponding theoretical predictions. This paper may serve as a reference on the correction of velocity measurements acquired by commonly used vane anemometers where flow test conditions of temperature,more » pressure, humidity, and/or density deviate from standard values.« less