steam turbine

I haven't heard of the terms minimum speed regulation and maximum speed regulation. Is the critical speed the critical speed? The steam turbine rotor has an inherent natural frequency. When the natural frequency of the rotor coincides with the frequency of the exciting force, resonance will occur. The speed at this time is the critical speed. When designing a steam turbine, its critical speed is required to be about 30% higher or lower than the operating speed. A steam turbine rotor whose operating speed is higher than the critical speed is called an orbiting rotor. This kind of rotor has a critical speed during the starting process. The critical speed of the rotor is related to the structure and material of the rotor.

The minimum speed adjustment and the maximum speed adjustment are not the speed adjustment ranges of the speed regulator. The speed regulator has a range within which the speed can be adjusted.

On the second floor, flexible rotor or flexible rotor, not winding rotor, I guess it was a typo. Most steam turbines have flexible rotors, and their critical speed is related to the support stiffness and system damping.

The speed of the steam turbine is regulated by controlling the opening of the speed regulating valve. It can only be effectively controlled within a certain range, so there is generally a speed regulating range, that is, between the minimum speed regulation and the maximum speed regulation.

It should be a range concept, and the speed controller should be used or set within this value.

Is what you are talking about the working range of the speed regulator?

Only those with regulating stages have minimum speed and maximum speed.

What do the minimum speed regulation, maximum speed regulation and critical speed of a steam turbine mean? The steam turbine is a large rotating equipment. It is started by passing through the warm pipe and opening the bypass door of the electric main steam valve to drive the rotor. By adjusting the opening of the bypass door of the electric main steam valve, it performs low-speed warm-up (500-600r/min) and medium-speed warm-up. (1000-1400r/min) The time of ground speed warm-up and medium-speed warm-up should be determined according to the expansion difference. After the medium-speed warm-up is sufficient, open the steam valve to increase the steam intake, so that the speed quickly exceeds the street speed (the definition of critical speed is introduced separately). As the steam intake increases, the temperature difference of the metal parts will increase, and it needs to stay at a certain speed for a period of time, which is high-speed warm-up. When the turbine speed rises to the point where the speed control system is put into operation, the turbine speed is controlled by the sculpture system. In the above introduction, the turbine speed is constantly changing from low to high. After reaching 3000r/min, the parallel and loaded steam turbine enters normal operation. We call the operating speed of the steam turbine also called the rated speed. critical speed of steam turbine: Since the steam turbine rotor is an elastic body, it has a certain vibration frequency. Centrifugal force causes forced vibration of the rotor. When the frequency of forced vibration matches the frequency of free vibration, that is, the number of changes in the direction of centrifugal force, causing the frequency of forced vibration of the rotor to be the same as, or proportional to, the frequency of free vibration of the rotor, resonance occurs. At this time, the vibration of the rotor is particularly large. This speed is called the critical speed of the rotor. critical speed of steam turbine: Refers to the speed of the steam flow. When the steam passes through the nozzle, the pressure drops and it acquires a certain speed. The speed at the smallest cross-section can only reach a certain limit value and does not exceed the speed of sound. This speed is called the street speed.