Experimental Stand for Very-Low-Velocity Gas Flow Generation

Area of Science:

• Fluid Dynamics
• Experimental Physics
• Metrology

Background:

• Accurate measurement of low-velocity gas flows is crucial for various scientific and industrial applications.
• Traditional methods can be complex or lack precision at very low speeds.
• A reliable and accessible method for generating and measuring low air velocities is needed.

Purpose of the Study:

• To develop and validate an experimental stand for generating constant volume air flows at very low velocities.
• To assess the accuracy of a novel water piston method for determining air-flow velocity.
• To compare the results from the water piston method with a standard technique, particle image velocimetry.

Main Methods:

• Utilized a Mariotte bottle and a water piston (water column) to generate a constant volume air flow.
• Determined air-flow velocity by measuring the change in water piston height over time using pressure differences.
• Employed particle image velocimetry (PIV) for independent velocity measurements for comparison.

Main Results:

• The experimental stand successfully generated air flows in the mean velocity range of 0.35-66 cm/s.
• The water piston method provided velocity measurements that agreed within 7% of those obtained by particle image velocimetry.
• The pressure difference across the water column correlated directly with the water piston's height change and thus air velocity.

Conclusions:

• The Mariotte bottle and water piston method offers a viable and accurate approach for generating and measuring very low gas flow velocities.
• This experimental setup provides a cost-effective and precise alternative for low-velocity fluid dynamics research.
• The high agreement between the water piston and PIV methods validates the reliability of this new technique.