Summer is coming. Are you ready to rely on air conditioning and fans? Driven by science and technology, modern fans have a more humane optimization, one of which is reflected in the fan blade.
I remember that the electric fans in my childhood were all three leaves, but today's fans seem to have many more seven leaves. Why? Today, purple rice is popular.
How good is the fan blade?
The initial three blade fan can form a reasonable mechanical power. Two blades in potential energy state can easily drive a blade that does not have potential energy temporarily to save power.
The 3-Blade electric fan is an early modern design. The wind is relatively direct and hard, which brings poor comfort to the human body.
With the progress of materials and technology, 5-leaf fan and 7-leaf fan were born one after another. The increase of blades needs to be matched with the update of materials and the improvement of motor technology, basicallyThe more the fan blades, the better the motor quality.
What is the shape of the fan blade?
Modern fans are generally shaped like bionic bird wings. Like the wings of birds, the air behind the machine is drawn into the fan blades and then sent forward. The flow of the blades is large and the noise is low, which conforms to the principle of fluid mechanics.
Why are all fans odd?
If an even number of blades are used, it is easy to produce resonance when rotating, resulting in fan damage and bearing wear.In fact, odd blades are widely used, such as helicopter propellers.
The principle of natural wind is that the heated air expands, lightens and rises, and cold air is added into the gap; The hot air will gradually cool down, and finally become cold air, and then fall back to the ground. This air flow produces wind.
The temperature, humidity and speed of natural wind are more diverse, which makes the air fresher. The fan just circulates the indoor wind continuously, so it can't be called natural wind.
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