Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Design and Calibration of a Pitot Static Probe for an Educational Subsonic Wind Tunnel
Submission Author:
Gustavo Pereira Miglioli , PR , Brazil
Co-Authors:
Gustavo Pereira Miglioli, William Alexander Carrillo Ibanez
Presenter: Gustavo Pereira Miglioli
doi://10.26678/ABCM.COBEM2023.COB2023-1640
Abstract
In order to instrument the educational subsonic wind tunnel, a Pitot-static tube was designed and calibrated for measuring airflow velocities. The tunnel’s test section has an area of 0.25 m2 and a velocity range of up to 15 m/s, facilitated by its 3 HP motor, allowing for aerodynamics studies on scaled F-SAE and AeroDesign models. The objective of this work is to determine the actual flow conditions in the test section, including the velocity profile, average velocity, volumetric flow rate, Reynolds number, and static pressure of the airflow stream. The Pitot-static probe was designed and constructed in accordance with the international ISO Standard 3966:2008, aiming to minimize intrusion into the flow. The uncertainties in velocity measurements were determined following the Brazilian NBR ISO Standard 5168. The construction methodology involved dividing the Pitot probe into three main parts: an ellipsoidal profile with a parallel orifice serving as the total pressure outlet, an inner tube as an extension of the pressure channel, and an outer tube with six holes perpendicular to the airflow for static pressure measurement. These parts were constructed from steel to ensure rigidity and quality, involving machining and welding processes. To facilitate the measurement of the velocity profile within the wind tunnel section, a vertical movement system was designed. The probe calibration was performed at multiple velocities, with three runs at each velocity to assess repeatability. Pressure readings were measured using a differential pressure sensor, along with an Arduino microcontroller that provided velocity values displayed on an LCD screen. The velocity uncertainty of the Pitot-static tube was determined to be 3.4% when compared with measurements obtained using a digital anemometer. Thus, this level of uncertainty indicates that the Pitot-static tube is a valuable tool suitable for didactic purposes.
Keywords
Pitot tube, Subsonic Wind Tunnel, Velocity Profile, pressure sensor, Arduino
