What is axial shift in turbine?

What is axial shift in turbine?

Axial shift on the Rotors comes due to two components. Direct Pressure Thrust: It is the axial thrust due the diff of the pressure X Area component across the moving stage blading and Discs. Velocity Component: It is due to diff.

What is the cause of steam turbine vibration?

The vibration is caused by insufficient clearance between stationary and rotating parts, as well as a shaft located off-center in its bearing. Again, the rubbing causes friction between stationary and rotating parts, localized heating of the rotor metal at the contact point, and shaft bending.

What is differential expansion in turbine?

Differential Expansion on a turbine is the relative measurement of the rotor’s axial thermal growth with respect to the case. Due to the mass of this case, it will expand and contract at a slower rate than the relatively thin (hollow) rotor.

What is turbine back pressure?

The term back pressure refers to steam turbines that exhaust steam at above atmospheric pressures. Between the mechanical power output of a condensing steam turbine and the power and steam combination of a back-pressure steam turbine, essentially any ratio of power-to-heat output can be supplied.

What is steam turbine critical speed?

Critical speed: It is the speed at which the center of mass is not equal to the center of rotation. Normally at these critical speeds the vibration is very high i.e. deflection of the shaft is infinity i.e. angular velocity (W) of the shaft = Critical angular velocity (Wc).

Why does turbine increase vibration?

VIBRATION DUE TO TURBINE SHAFT RUBBING:- Due to rubbing of moving parts of the rotor with the stationary part of the rotor an impress a layer of metal on the surface of the rotor. The shaft bending will usually cause increased vibration into the steam turbine.

What are the causes of serious damage of turbine blade?

Turbine blades are subjected to very strenuous environments inside a gas turbine. They face high temperatures, high stresses, and a potentially high vibration environment. All these factors can lead to blade failure, resulting in catastrophic failure of turbine.

What is rotor in turbine?

rotor, rotor coil – the rotating armature of a motor or generator. stator, stator coil – mechanical device consisting of the stationary part of a motor or generator in or around which the rotor revolves. steam turbine – turbine in which steam strikes blades and makes them turn.

What is a high pressure turbine?

High pressure turbine: The high pressure (HP) turbine (see Figure 1) is the first main engine turbine to receive steam from the main steam system. It is designed to efficiently extract work out of high pressure steam. The HP turbine is a pressure-velocity compounded, single axial flow, non-condensing impulse turbine.

Why back pressure turbine is called back pressure?

If only a proportion of the steam passing through the first stages of the turbine is used for process heat, the unit is called a pass-out turbine. If all the steam is used for process heat, the unit is called a back-pressure turbine.

What is the axial shift of a steam turbine?

Axial shift of a steam turbine is the shifting of turbine rotor in the forward and backward direction due to steam thrust on blades of rotor.

What causes the bearings of a turbine to wear out?

Very High: The excessive temperature rise of bearings can cause wear to bearing shells Bearing temperature trip protects the thrust and journal bearings of the Turbine and Generator against excessive temperatures.

Is the trip preceded by de-loading of turbine?

Usually a Trip is preceded by an “de-loading of turbine” as per Turbine manufacturer recommendation. Action: 86T Turbine Trip Conditions 86T – Main Steam Temperature Low

Why does HP turbine run at low flow rate?

Under extreme operating conditions the HP turbine can be run at low flow rate and simultaneous relatively high back pressure. This prevents the steam from expanding, which causes the exhaust steam temperature to rise.