What is the working principle of a bladeless electric fan?

The base of the bladeless fan is equipped with a centrifugal compressor, which sucks the air around the base with the rotation of the blades, pressurizes it and pushes it to the hollow tubular ring at the top of the fan. The upper end of the tubular ring is provided with a narrow slit, air is ejected from the narrow slit, and the ejected air advances along the inner wall of the tubular ring in the ejection direction;

Because the cross section of the inner wall is wing-shaped, based on Bernoulli's law, a low pressure is formed on the inner wall surface of one side of the air injection ring, thus forming a low pressure in front of the center of the ring, and the air behind it is pulled forward, so that a large amount of air in the ring is pulled and injected.

In james dyson's original design, a brushless motor was used in the base to drive the compressor to suck in 27L air per second, while the annular air outlet device had 405L air per second. Sir james dyson, an industrial designer, named his fan "Air Multi-effect Device".

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Spanish consumer protection organization Organizació n de Consumidores y Usual IOS tested Dyson's first air multiplier (AM0 1) and evaluated the more profound and stable air flow.

It is found that its maximum setting takes 40W, and it moves 2700m/h ... However, it is noisier and more expensive than the vane fan (300-400 Euros versus 20 Euros). Another test found that the power consumption of AM0 1 varied between 2-3W and 31W.

Geek.com measured the airflow, noise level and power of AM06, and found that besides the first setting, it also achieved a similar level of wind speed and the amount of air moving per second, while being quieter (2- 10? dB？ ) and more energy per moving air volume (6-3 times) according to the setting.

It is reported that the highest setting is 1 150ft? /min ( 1950m？ /hour) and 548 feet/minute (2.7 meters/second). The volume is equivalent to an ordinary fan of $80, which is about twice that of 15, and the wind speed is roughly equivalent to both.

Under this setting, the noise generated by AM06 is 10dB lower than that of ordinary fans, using 20W, and ordinary models using 60W and 40W.