(Daily Question) Coal-to-oil and olefins forum, April 23, 2018

Due to factors such as material, manufacturing, and assembly, it is impossible to achieve perfect balance in the rotors of turbines and compressors; there is always an eccentricity between their centers of mass and the axis. When rotating at high speeds, the presence of an eccentricity causes unbalanced masses within the rotor to generate periodic disturbing forces and torques. When the frequency of these disturbing forces and torques acting on the rotor is equal to or close to the rotor’s natural vibration frequency, the machine experiences intense vibrations; this phenomenon is known as resonance. The speed at which resonance occurs in a machine is referred to as the critical speed.

The rotors of turbines and compressors rotate at high speeds. When they operate at a certain specific speed, the compressor becomes unstable, experiencing severe vibrations; the rotor bends significantly, and friction between the rotor and its fixed components causes damage to the machine. Once the speed moves away from this value, the vibrations return to normal. This specific speed is known as the critical speed.

The rotors of turbines and compressors rotate at high speeds. When they operate at a certain specific speed, the compressor becomes unstable, experiencing severe vibrations; the rotor bends significantly, and friction between the rotor and its fixed components causes damage to the machine. Once the speed moves away from this value, the vibrations return to normal. This specific speed is known as the critical speed.

The rotors of turbines and compressors rotate at high speeds. When they operate at a certain specific speed, the compressor becomes unstable, experiencing severe vibrations; the rotor bends significantly, and friction between the rotor and its fixed components causes damage to the machine. Once the speed moves away from this value, the vibrations return to normal. This specific speed is known as the critical speed.

Turbine and compressor rotors rotate at high speeds; when they operate at a certain specific speed, the compressor becomes unstable, experiencing severe vibrations. The rotor bends significantly, and friction between the rotor and its fixed components causes damage to the equipment. Operation is stable outside this speed, and this speed is known as the critical speed.

Due to factors such as material, manufacturing, and assembly, it is impossible to achieve perfect balance in the rotors of turbines and compressors; there is always an eccentricity between their centers of mass and the axis. When rotating at high speeds, the presence of an eccentricity causes unbalanced masses within the rotor to generate periodic disturbing forces and torques. When the frequency of these disturbing forces and torques acting on the rotor is equal to or close to the rotor’s natural vibration frequency, the machine experiences intense vibrations; this phenomenon is known as resonance. The speed at which resonance occurs in a machine is referred to as the critical speed.

Turbine and compressor rotors rotate at high speeds. When they operate at a certain specific speed, the compressor becomes unstable, experiencing severe vibrations; the rotor bends significantly, and friction between the rotor and its fixed components causes damage to the machine. Once the speed moves away from this value, the vibrations return to normal. This specific speed is known as the critical speed, or resonance speed.

The rotors of turbines and compressors operate at high speeds. When they run at a certain specific speed, the compressor becomes unstable, experiencing severe vibrations; the rotor bends significantly, and friction between the rotor and its fixed components causes damage to the machine. Once the speed moves away from this value, the vibrations return to normal. This specific speed is known as the critical speed, or resonance speed

This post was last edited by 68ZCW on 2018-4-23 at 21:37. The various components of turbines and compressors are highly precise, and they are balanced during assembly. However, it is still not possible for the center of gravity of these turbines and compressors to exactly coincide with the center of the shaft. Due to the discrepancy between the center of the shaft and the center of gravity of the rotor, centrifugal force is generated as the shaft rotates, and this is the main cause of vibration in turbines and compressors as well as bending of the shafts. As the rotor rotates, its center of gravity moves along the axis line, and the direction of the centrifugal force also changes as it rotates. One vibration occurs each time the axis completes one full rotation, and the number of such forced vibrations per second is known as the frequency of the forced vibration. The rotors of turbines and compressors are elastic bodies with certain natural frequencies. Resonance occurs when the frequency of forced vibration of the rotor coincides with its natural vibration frequency – that is, when the frequency causing the forced vibration of the rotor is the same as or proportional to its natural frequency. At this point, the vibration of the rotor becomes extremely severe, and this rotational speed is known as the critical speed.

Due to factors such as material, manufacturing, and assembly, it is impossible to achieve perfect balance in the rotors of turbines and compressors; there is always an eccentricity between their centers of mass and the axis. When rotating at high speeds, the presence of an eccentricity causes unbalanced masses within the rotor to generate periodic disturbing forces and torques. When the frequency of these disturbing forces and torques acting on the rotor is equal to or close to the rotor’s natural vibration frequency, the machine experiences intense vibrations; this phenomenon is known as resonance. The speed at which resonance occurs in a machine is referred to as the critical speed.