In a bladeless fan, Air-multiplier has made of the brushless electric motor or BLDC motor. Let’s have a little discussion on the brushless electric motor. In a typical DC motor, there are permanent magnets on the outside and a spinning armature on the inside. The permanent magnets are stationary, so they are called the stator. And the armature rotates, so it is known as the rotor. Here is a brushless DC motor (BLDC), the permanent magnets are present on the rotor and you move the electromagnets to the stator. Then when you supply power to the stator, that contains an electromagnet, it creates a magnetic field in the stature that attracts and repels the permanent magnets of the rotor. That’s how the BLDC motor works. Now, see the role of this BLDC motor in an Air-multiplier.
In a bladeless fan, Air-multiplier is present at the bottom. A small brushless electric motor runs a tiny fan with asymmetrically aligned blades that push air through a set of stationary blades that smooth the airflow. After that this air is directed towards the hollow-circle-like tube at the top of the device where it’s forced out of a circular narrow slit or opening running around the circle. At the base of the hollow circle, the openings are wide. But it narrows near the top of the hoop or circle, this structure provides the first step to the multiplication of air. The airflow induces the air behind the hollow circle to be pulled along too; this is the second step of air-multiplication. Air surrounding the edge of the hollow circle or hoop is drawn through in the same direction as the electrically propelled air.
Most of the manufacturers of bladeless fans are doing multiple changes in the design of the Air-multiplier to improve the quality of the breeze of this fan.