Design and Calibration of a Low Speed Wind Tunnel

A low speed, open circuit, laboratory wind tunnel was designed and built to facilitate the testing of airfoils designed for use with straight bladed vertical axis wind turbines. The wind tunnel built was the open-circuit type and was chosen due to the ease of fabrication and low construction costs associated with the build. Wind speed through the tunnel was controlled by a variable speed WEG 3.00 hp motor drive unit with a WEG CFW 08 vector inverter plus motor speed control unit. Calibration tests were performed using a hot-wire anemometer to determine the wind velocity as a function of differential pressure measured using a pressure transducer. The characteristic curve of wind velocity vs inches of water was plotted. The velocity profile for this wind tunnel indicated a turbulent flow regime and there was a good second order polynomial relationship between the measured velocity and differential pressure drop.