Why a Wind Tunnel Needs More Than a Fan
A low-speed wind tunnel needs a controlled stream around a stationary model. In an open-return arrangement, the drive fan draws air through conditioning elements, a contraction and the test section before it reaches the diffuser.
Follow the air through the process
Condition the incoming air
Honeycomb passages limit sideways motion. Screens help reduce velocity differences, but their arrangement also affects pressure loss and flow quality.
Accelerate through the contraction
A narrowing passage reduces the flow area. At the same volume flow, the smaller test-section area has a higher average air velocity.
Check the model and its supports
The model, mounting hardware and measuring probes form the test arrangement. Their positions can disturb the flow being studied.
Connect the diffuser to the fan
The diffuser expands the passage after the test section. Its shape and connection to the drive fan must be assessed with the rest of the circuit.
Airflow function
- Provide the pressure rise needed to move air through the complete circuit.
- Support the required test-section speed range.
- Integrate with the diffuser, fan housing, mounting and controls.
What can change the result
- A running fan does not establish uniform velocity or low turbulence.
- Changing a screen arrangement can change the total-pressure profile.
- A fan selected without the installed circuit resistance may miss the intended duty.
Start with the complete air path
Share your layout and the information you already have. Unknown values can be identified before a configuration is selected.
Match the fan to this air path
LONGWELL EC axial motor-and-impeller families can be reviewed as drive-component candidates for suitable low-speed tunnel development. Share the operating range and circuit resistance before selecting a family or model.
Where it sits
At the downstream drive position of the illustrated low-speed open-circuit tunnel, following the diffuser. Housing and inlet connections are part of the assembled circuit.
Why consider this configuration
A controllable axial component is a candidate when its operating range covers the complete circuit losses. Flow conditioning and tunnel geometry determine the quality of the air reaching the model.
Check the result in your equipment
Application questions
Does higher fan speed guarantee better test data?
Higher speed changes the operating point. Flow quality also depends on the conditioning elements and complete test arrangement.
Can more screens always improve the flow?
Screen changes can improve some flow characteristics while changing pressure losses or the pressure profile. Verify the chosen arrangement.
Is the illustrated airflow a measured result?
The animation explains the component layout. Actual flow quality must be established on the assembled tunnel.
Discuss your tunnel drive requirements
Send the test-section area, speed range and circuit layout, including screens and honeycomb. Add the expected pressure losses, mounting and flow-quality verification plan.
A layout, installation photos or your existing model is enough to start the discussion.