A bladeless fan uses the Coanda effect and Bernoulli’s principle of fluid dynamics to generate wind without wings. Safe and efficient thanks to its mechanical design, this innovative product is the result of the application of the principles of fluid dynamics in various fields.

Mechanical engineering and a fan without blades

The first appliance that comes to mind during the summer months is the electric fan. Not only are they cheaper than air conditioners, but they also save money on electricity, so you don’t have to worry about running them all day. As a result, sales of electric fans skyrocket during the summer months, and a new product called a ‘bladeless fan’ has become very popular in the seasonal appliance market this year since it was first introduced in 2009. As the name suggests, it’s a new type of fan that, unlike traditional fans with blades, produces air from a slim, circular ring. The main advantage of a bladeless fan is that it’s much safer, as you don’t have to worry about hurting your hands on the blades. If they don’t have blades, how on earth can they create wind?
The truth is, it’s not that the blades are missing, it’s that the blades that create the wind are hidden in the bottom of the fan, along with the motor. Specifically, to explain how the wind is formed, the fan and electric motor at the bottom of the fan work to draw outside air into the machine and send it upwards. This air rises above the outlet and spins along the surface of the circular ring, and as it is expelled forward, it draws air behind the fan, creating a large amount of wind. This process utilises principles of hydrodynamics such as the Coanda effect and Bernoulli’s principle.
The Coanda effect is the tendency of a fluid to adsorb to a surface when it flows over a gently curved surface. For example, if you’re working out hard and sweating profusely, you might notice that the sweat that runs down your head or forehead tends to trickle down your jawline or neckline instead of dripping directly to the ground. Another example is when water from a tap runs along the surface of a spoon. This effect causes air travelling along the surface of the circular ring at the head of an electric fan to flow rapidly along the inner surface of the ring.
Bernoulli’s principle states that the faster a fluid moves, the lower its pressure, and the slower it moves, the higher its pressure. Think of a car travelling fast on an unobstructed road versus a traffic jam: if there’s an empty road next to it, the cars stuck in traffic will want to go there. Similarly, fluids will try to move towards the faster side of the road because the pressure is greater on the slower side. Applying this principle to a fan without blades, a flow of fast air is formed through a small gap at the end of the circular ring at the head of the fan, which lowers the pressure of the air, causing the air at the back of the fan, where the pressure is higher, to move forward. In this process, 15 times more air is moved than is sucked in from the bottom of the fan, creating the wind.
There’s a scientific principle behind the bladeless fan that has to do with the properties of fluids. The way a regular fan produces wind is also based on the principles of fluid dynamics. In fact, the principles of fluid dynamics are applied in many different ways around us. It’s not just fans, it’s airflow in aircraft wings and engines, and how salt flakes float on water. Depending on where and how these principles are applied, they can be groundbreaking ideas or just ordinary technology. So who are the people who understand the properties of these fluids and apply innovative ideas in real life? Mechanical engineering students. The Department of Mechanical and Aerospace Engineering is constantly working to study the properties of fluids and apply them to real life in a more convenient and advanced way.

Applications of fluid dynamics and the scalability of the bladeless fan

The principles of fluid dynamics used in the bladeless fan have applications in many different industries. For example, Bernoulli’s principle plays an important role in controlling airflow in aircraft. Aircraft wings ensure stability in flight by properly regulating airflow, which is also true in the automotive industry. The aerodynamic design of a car is used as a key technology to improve the fuel efficiency of the vehicle and increase its stability when travelling. These improvements in aerodynamic design can also be applied to improve the performance of household appliances, such as fanless fans. Further developments in this principle could even maximise the efficiency of bladeless fans or create new types of appliances.

The future of mechanical engineering and its continued development

Mechanical engineering continues to evolve today, fusing with a variety of advanced technologies to create new products and ideas. For example, smart appliances combined with artificial intelligence (AI) maximise user convenience, and the Internet of Things (IoT) is playing an important role in maximising the efficiency of mechanical devices. Household appliances such as bladeless fans can expect to continue to improve with these technological advances, and research into the utilisation of green energy is particularly active. Mechanical engineering will continue to drive sustainable development in the future by developing environmentally friendly and energy-efficient technologies.