Hi there.
I'm relatively new to this field and I wonder is there any small and cheap air flow sensor with a detection range of around 2 up to 55 L/min with less than 15% error and fully compatible with arduino(UNO)?
Pitot tubes are far from accurate for my purpose(slow speed), and accurate sensors like Omron D6F are limited to only a few Liters/minute.
To be clear I want to measure the air flow passing through a hole with a diameter of around 1 to 2cm and flow speed of 1 to 11 m/s(pretty much like human trachea)
These sensors are/can be very sensitive to flow turbulence and distortion. We used some to measure the 3D steam flow across a channel at 40 kHz sampling rate. I.e. the sensors may be too sensitive for certain applications.
Right. How do you define "accurate" if the flow profile is unknown? In laminar flow the speed degrades from mid to border of the channel or can be asymmetric.
Hot wire sensors detect wind speed, not volume. Accurate volume determination requires to integrate the speed over the entire channel cross-sectional area, together with pressure and temperature.
That's why hot wire sensors are not very usable to determine flow volume.
Run several in parallel to get the required flow rate, or use one in a shunt arrangement with one or more parallel tubes that bypasses the majority of the air. Make the length, width and surface finish of the bypass tubes the same as the sensor so you can multiply the single measurement by the total number of tubes.
Keep in mind that air is a FLUID and as such does not FLOW without turbulence and different speeds depending on where the sensor is placed. Flow at the surface of the container is almost zero. So any error you anticipate may be related to fluid flow and not sensor capability.
