Fan: Bladeless Fan

This project simulates the airflow inside a bladeless fan using ANSYS Fluent, with fan aerodynamics as the central theme. Unlike a conventional fan, a bladeless fan generates no airflow with moving blades; instead it draws air in and amplifies it through fluid-dynamic principles and air-multiplier technology. This brings real advantages — it is safer, with no exposed moving parts (an important benefit in homes with children or pets), and more energy efficient, since no motor is needed to spin a set of blades. The core of the study is to show how this multiplier effect arises purely from the geometry and the resulting flow field.

The operating principle, as captured in the simulation geometry, proceeds in three stages. First, air intake: four square inlets, each 21 mm on a side, sit in the fan's cylindrical base of 0.2 m diameter and draw in the surrounding air. Second, air amplification: this air is forced into a 0.52 m-diameter cyclone section and channelled along an airfoil-shaped ramp, which makes it spiral and accelerate. As the flow passes over the curved upper surface of the airfoil it creates a region of negative pressure that speeds the air up and entrains far more surrounding air — multiplying the original flow roughly sixteen-fold — producing a safe, low-velocity, smooth stream without any blades. Third, air ejection: the high-speed air is expelled through a thin slit in the fan's top circular loop, giving the steady, continuous cooling stream that distinguishes a bladeless fan from the choppy output of a conventional one.

The geometry was created in Design Modeler and meshed in ANSYS Meshing with 1,927,707 cells.

The simulation reproduces this air-multiplier behaviour by resolving the internal flow field. From the inlet volumetric flow rate of 0.01 m³/s, the inlet velocity is 5.67 m/s. The standard k-ε turbulence model is used, which suits this application because the flow within the fan — especially through the cyclone section — is fully turbulent, a regime in which the model gives reasonably accurate predictions.

The results are presented as contours, vectors and pathlines. The velocity pathlines reveal how the air is drawn into the cyclone and accelerates as it follows the airfoil ramp, while the pressure and velocity contours over the chosen planes highlight the low-pressure region generated over the airfoil and the resulting velocity distribution. As a study in fan airflow modelling, the project demonstrates how CFD can capture the air-multiplier mechanism of a bladeless fan — showing how geometry alone, through a region of negative pressure, entrains and amplifies a small intake flow into a smooth, high-volume output stream.