How to deal with excessive air volume of centrifugal fan?

How to deal with the excessive air volume of the centrifugal fan?

China has manufactured simple wooden hulled windmills in many years BC, and its working principle is basically the same as that of modern centrifugal fans. In 1862, Guibel of the United Kingdom invented a centrifugal fan. Its impeller and casing are concentric circles, the casing is made of bricks, and the wooden impeller is made of straight backward blades. The power is only about 40%. It is mainly used for mine ventilation. In 1880, people planned a volute casing for mine exhaust and air supply, and a centrifugal fan with backward curved blades. The structure was relatively complete. In 1892, France developed a cross-flow fan; in 1898, the Irish planned a forward-blade Sirocco centrifugal fan, which was widely used by various countries; in the 19th century, axial flow fans were used in mine ventilation and metallurgical industry. However, the pressure is only 100-300 Pa, and the power is only 15-25%. It was not until the 1940s that it was quickly developed.

Centrifugal fan is a kind of driven fluid machine that relies on input mechanical energy to increase gas pressure and discharge gas. It can be made into two types, right-handed and left-handed. From the side of the motor, the impeller rotates clockwise, which is called right-rotating fan and counterclockwise, which is called left-handed. The working principle is basically the same as that of a turbo compressor, except that the gas flow rate is low and the pressure is not changed much. Generally, there is no need to consider the change of the gas specific volume, that is, the gas is treated as a non-compressible fluid. The air volume of the centrifugal fan of the new device will be too large. When the fan starts to operate after the new device, or is too large or too small during use, one of the following methods can be used to eliminate it: change the speed of the fan to adjust the flow rate. Use the degree of opening and closing of the regulating door to regulate the flow rate. Change the resistance coefficient of the pipe network to adjust the flow. Exchange the higher or lower pressure fan to adjust the flow rate.