The principle of ventilation and cooling of large industrial fans?

The large industrial ceiling fan runs in an ideal situation. You can imagine the wind blown by the super large industrial fan as a columnar airflow. The outer surface of the columnar airflow will have friction with the air. The resistance = K1 (resistance constant) * perimeter ventilation Quantity = k2 (speed constant) * cross-sectional area. Compare a fan with a diameter of 730mm and a super large industrial fan with a diameter of 7300mm:

1. Fan with a diameter of 730mm: perimeter = 0.73 × 3.14 = 2.29m cross-sectional area = 0.36 × 0.36 × 3.14 = 0.407 square metersChina EC Fans Manufacturers

2. Fan with a diameter of 7200mm: perimeter = 7.2 × 3.14 = 22.9m cross-sectional area = 3.6 × 3.6 × 3.14 = 40.7 square meters

It can be seen that the resistance of the large fan passing through the same area of ​​air flow is 0.1 times that of the small fan

Principle: The friction force of the large airflow fluid movement is relatively small, so that the large fan can drive a large amount of air but the energy required by the small fan is relatively less! Once the inertia of the air is overcome, the kinetic energy of the large air flow Only a small follow-up power is needed to maintain the continuous flow of air. The airflow friction of the small fan is relatively large, and most of the energy is lost in the friction process.