Unique Blade Profiles – for moderate air and low noise Ceiling Fans

Vrushali Joshi Mukherjee, Sandevin Analytics

Look around you and you would notice a rapidly increasing trend of Low noise (noiseless as some term them) Ceiling Fans which may give only moderate air delivery, designed especially for AC rooms. Having done away with the noise of Window air conditioners, the fan noise seems a bother. This trend surely brings a greater role of Blades design /configuration/aerodynamics and the role of experts in the same. Material substitution which has already been embarked upon by most leading brands too will have a role to play.

There are two classes of affluent Indian Customers.

One who want just white or plain fans without embellishments and want fans in décor to be non-intrusive. Others are the ones who want fans to supplement the décor value of the room with some unique looks and aesthetics. So far, in past 40 years or so, the aesthetics have largely been focused on motors/color shades or metallic finishes. On blades it was the geometrical design or embellishments on it called blade trims.

The world has meanwhile moved on to the unique blade profiles. Not just an option of 3 or 4 or 5 blades and not just the material change. What is interesting is that these aesthetically entirely different blade profiles also appeal to the class of people who as of now like non-intrusive fans.

Look at some concepts floating around in the world today.

Highly twisted fan, it will help to increase Air delivery at low speed.
Folded blade, in single blade it will work as double blade combination as well as noise will be lower because of closed tip
Highly twisted and higher width fans, will give higher Air delivery.
Alternate Blade combination (big and small). In this combination of one big and one small, it creates combined effect. It can be designed to give higher Air delivery and spread.

Now these types and more interesting designs like these are the smart thoughts of industrial designers but the Aero Designers (experts in Aerodynamics) have an equally or more role to play. It is a collaboration of two minds to produce “Wow effect “fans.

Let it be explained a bit more about the role of Aerodynamics on such unique designs.

So, why should we care about aerodynamics? Why does it matter? Have you ever ridden in an open-top car and felt the wind pushing past your face? It’s exhilarating and you feel really alive. Aerodynamics is all about studying physics behind moving objects. Understanding how air behaves when we slice through it at speed is incredibly important.

With the aerodynamics expert involved, optimum blade shape using aerodynamics characteristics are calculated. In fans blades used to transform the kinetic energy in the wind and it has to be designed carefully to enable to absorb energy with its greatest efficiency. They have several advantages in meeting the intrinsic requirements for wind in terms of design point, off-design capabilities and structural properties. Although it can involve very complex math, the basic principles include how fluids flow in different ways, what causes drag (fluid resistance), and how fluids conserve their volume and energy as they flow.

Ideally, we want to shape the blade so the flow of air around it is as smooth as possible—so it’s laminar rather than turbulent. The more turbulence there is, the more air resistance the fan will experience, the more energy it will consume, and shall result in lower performance and higher noise. Material of blade is also an important parameter.

Another interesting trend noticed in the recent times in fans is that dual blades are employed. This trend is in both Ceiling Fans as well as Portable fans. Have a look at LG ceiling fan launched in India and here is an image of another fan possibly for kids’ room. The benefits claimed with this addition are yet to be validated but the trend surely needs a close watch.

LG Smart fan with dual blades

So, get the industrial designers and aerodynamic experts collaborate and let the brand stand apart with unique models.