You must be wondering how fans can be bladeless. It all began when the famous electronics company called Dyson introduced a bladeless fan known as Air Multiplier in 2009. Many competitor companies have launched bladeless fans so the market is loaded with such products nowadays. Bladeless fans are gaining popularity over conventional fans as they are more power-efficient, produces less noise, safe, and easy to maintain with no blades.
Most of the bladeless fans seem to have a hallowed round tube that is fixed on a pedestal. When you look at the device, it's hard to imagine breeze or air coming out of a circular rim with no moving fan blades or components. So how does bladeless fan work?
Working of a Bladeless Fan
Design and Functioning:
There are some scientific principles including aerodynamics and physics that involve and multiplies the air. It all begins when the air enters through small slits at the base of the fan. Some models are small intake holes that align so air is even inside the device. The secret is that these fans do have 8 to 9 blades that have an asymmetrical position and hides in the fan’s base. It also comprises an electric brushless motor that rotates and the blades pull air from openings and push through small slits around the ring of the fan to create basic airflow. These blades are capable of sucking air to about 5.8 gallons per second.
In traditional fan, when airflow has to change direction, the disrupted air is turbulent which is noisy and wastes energy. In bladeless fans, turbulence minimizes greatly to ensure more quiet and efficient performance. To cut down all the noise, a helmets cavity captures and dissipates the motor noise. Moreover, the engineered acoustic motor casing isolates all the vibrations.
This is not the end of the story! To multiply the initial airflow, bladeless fans use 3 mechanisms. First, when air pushes through the narrow slits around the ring, surrounding air pulls along with it. The name of this air multiplier process is entrainment. Next is the fluid dynamics principle, inducement. The ring is slightly thicker in the back and thinner at the front of a fan just like an airplane's wings. Air exiting the slit flows along the curve instead of moving in a straight path. According to Bernoulli’s principle, the faster a stream goes the less pressure it exerts. We call it the Coanda effect that creates a zone of low pressure in the inner region.
The low pressure allows air from behind the fan to be pulled to front creating more airflow. Finally, the jet of air that exits the ring further entrains air from the outer regions adding to the airflow. As a result of these three combined mechanisms: between inducement and entrainment, a bladeless fan’s output airflow increases to about 15 to 20 times that keeps your face cool throughout the hot days. This is how air multiplier or bladeless oscillating fan projects smooth powerful and high-velocity airflow.