What is the principle of centrifugal compressor?

The increase of air pressure in centrifugal compressor is realized by impeller rotation and diffuser expansion. According to the level of exhaust pressure, it can be divided into three categories: centrifugal fans, and the wind pressure is within or below 10- 15kPa; Centrifugal blower, the wind pressure is in the range of 15~350kPa; Centrifugal compressor, the wind pressure is above 350kPa.

The impeller of centrifugal compressor does work on gas, increases the pressure and speed of gas, and completes the transportation of gas. Gas flows through a compressor with a radial impeller.

Also known as turbo compressor: it is mainly used to compress gas, and it is mainly composed of rotor and stator: the rotor includes impeller and shaft, and the impeller is provided with blades, balance disc and a part of shaft seal; The main body of the stator is a cylinder, and there are devices such as diffuser, elbow, reflux device, air pipe and exhaust pipe.

Working principle of centrifugal compressor;

When the impeller rotates at high speed, the gas rotates with it. Under the action of centrifugal force, the gas is thrown into the diffuser behind, forming a vacuum zone at the impeller, and fresh air from outside enters the impeller at this time. The impeller rotates constantly, and the gas is continuously sucked and thrown out, thus maintaining the continuous flow of gas. Compared with reciprocating compressor, centrifugal compressor has the following advantages: compact structure, small volume and light weight; Continuous and uniform exhaust, no tundish and other devices are needed; Small vibration, few wearing parts, no need for huge and bulky basic parts; Except bearings, there is no need for lubrication inside the machine, which saves oil and does not pollute compressed gas; High speed; Small maintenance and convenient adjustment.

The main components of centrifugal compressor for compressing gas are impeller rotating at high speed and diffuser with increased flow area. In short, the working principle of centrifugal compressor is that the impeller does work on gas, and through centrifugal pressurization and deceleration expansion, mechanical energy is converted into pressure energy of gas in the impeller and diffuser flow passage.

More generally speaking, when the gas flows through the impeller of the centrifugal compressor, the impeller running at high speed makes the gas under the action of centrifugal force, on the one hand, the pressure increases, on the other hand, the speed is greatly improved, that is, the centrifugal compressor first converts the mechanical energy of the prime mover into the static pressure energy and kinetic energy of the gas through the impeller. After that, when the gas flows through the diffuser, the cross section of the channel gradually increases, the velocity of the gas molecules in front decreases, and the gas molecules in the back continue to flow forward, so that most of the kinetic energy of the gas is converted into static pressure energy, which further plays a role in boosting pressure. Obviously, the work done by the impeller on gas is the fundamental reason for the increase of gas pressure, and the work done by the impeller on gas per unit time is closely related to the peripheral speed of the impeller outer edge. The greater the circumferential speed, the greater the work done by the impeller on the gas.