Bladeless fans have been recently introduced in the market but they are an old concept. This concept was first put up by the Japanese multinational conglomerate Toshiba. The company came up with the idea that a fan be made which had no blades at all. The time this idea was put up, the world was aroused with curiosity as well as shocked that how will this work? A fan without any blades, will it even work? There were many questions starting with is this a technical joke? How will the fan work, what is the basic principle that will make the fan work? And a few other questions like these were prevailing in the minds of the people at that time.
The confusions of this being a joke were answered when the fan was introduced to the general public in 2009 by Sir James Dawson. The pioneer in the field is still an area of controversy. The Toshiba company claims that they had presented the concept and lay claim to the patent but the us patent records has the patent under the name of James Dawson. Regardless of that, the unveiling of the fan proved that the fan does exists and it is efficient, les noisy and better that the fans with blades.
The single remaining question
The one question as to how the fan works will be answered here.
The fan takes into use the concepts of general physics along with a few concepts of aerodynamics to multiply the air sucked from the slits of the base. This process takes into use very low amounts of energy and also creates less noise.
The process begins when the air is sucked in from the base and a small motor with asymmetrically arranged blades pushes it over many stationary blades which smoothes the airflow. From there the smooth airflow is pushed in the loop or hoop like structure of the fan. The air circulates inside the hoop structure and is ejected from very narrow slits which are running along the complete hoop of the fan.
The steps of air multiplication
The slit running along the hoop is very narrow and the slits at the base of the fan are wider which creates an air flow in speed. It is a similar to the result created when we put our finger and narrow the slit of the pipe carrying water. This point is the first point of multiplication of air.
The further multiplication happens due to the fin like blade inside the hoop which is like the aircraft fin and the air flows as per the fluid dynamics principle of fluid inducement. The air induces the air behind it to flow or follow the flow it is in. This makes the air to flow in a loop like structure when it ejects from the slits of the hoop.
The last air multiplication occurs due to the fluid dynamics principle of entrainment. This summed up together allows the air to be multiplied 15 times than what was taken in. for example if the air multiplier or the bladeless fan takes in 15 litres if air it can pump up to 225 litres of air which is very much efficient. You can read more about bladeless fans and try it out at this link.