it's the thermal expansion in the casing of hp or ip turbine
can be noticed by journal or thrust bearing when moving <<
It is an engine.A steam turbine is a heat engine that uses the expansion of steam passing through stationary nozzles and blades on a shaft to turn the shaft. The steam can move through the turbine axially (one end of shaft to the other end), radially (shaft to outer casing), or tangentially (around the outer edges of the turbine wheel). In an impulse turbine, the steam is expanded in nozzles and pushes the blades. In a reaction turbine the steam is expanded in the nozzles AND in the blades, the reaction of the expansion of the steam pushes away from the blades spinning the wheel in the process. The expansion of the steam is necessary to increase its velocity through the turbine.
by controlling main steam flow
Negative differential expansion in a steam turbine refers to a condition where the thermal expansion of the turbine components is not uniform, causing the rotor and casing to expand at different rates. This can lead to increased stresses and potential misalignment, negatively impacting the turbine's efficiency and longevity. Proper design and operational practices are essential to mitigate these effects and ensure optimal performance.
Two triple expansion steam engines and an exhaust turbine
multistage is used because the expansion of high pressure steam will be gradual and as a result the rotor wont vibrate.suppose we have only 1 stage of blades in a turbine, hence all the steam will expand in the given stage and the speed of the rotor will be in high range around 30,000m/s, which is very difficult to control and operate the turbine.
my LP turbine differential expansion increase ,when rated gland steam temperature maintain.
It is an engine.A steam turbine is a heat engine that uses the expansion of steam passing through stationary nozzles and blades on a shaft to turn the shaft. The steam can move through the turbine axially (one end of shaft to the other end), radially (shaft to outer casing), or tangentially (around the outer edges of the turbine wheel). In an impulse turbine, the steam is expanded in nozzles and pushes the blades. In a reaction turbine the steam is expanded in the nozzles AND in the blades, the reaction of the expansion of the steam pushes away from the blades spinning the wheel in the process. The expansion of the steam is necessary to increase its velocity through the turbine.
Axial displacement is the motion along the shaft of the turbine caused by the force exerted by the steam or by the thermal expansion of the shaft and casing.
by controlling main steam flow
Two triple expansion steam engines and a small turbine
In a low-pressure (LP) turbine, the rotor expansion is greater than the casing due to the design and operational conditions of the turbine. The rotor experiences a significant drop in pressure and temperature as steam expands through the turbine stages, resulting in a larger volumetric increase compared to the casing, which is designed to contain the steam flow with minimal expansion. This difference allows for efficient energy extraction from the steam, optimizing the turbine's performance while maintaining structural integrity in the casing. Overall, the rotor's greater expansion accommodates the dynamic changes in steam properties as it moves through the turbine system.
Turbine diff expansion can be positive or negative and depends on the convention used. The usual convention is that positive expansion is rotor expanding faster (hotter) than fixed components. Expansion is dictated by steam flow, gland steam temperatures etc
Negative differential expansion in a steam turbine refers to a condition where the thermal expansion of the turbine components is not uniform, causing the rotor and casing to expand at different rates. This can lead to increased stresses and potential misalignment, negatively impacting the turbine's efficiency and longevity. Proper design and operational practices are essential to mitigate these effects and ensure optimal performance.
Two triple expansion steam engines and an exhaust turbine
Because the steam expands as it passes through the turbine. The steam velocity through the turbine is constant from steam chest to exhaust hood (though it changes in each stage). Thus, the space needed for the steam to expand needs to be expanded to correspond with that expansion of the steam.
The volume increases in each turbine stage as the expanding steam passes through the turbine blades. This expansion of steam causes an increase in volume and a corresponding decrease in pressure and temperature.
Back pressure is the small amount of vacuum that is created when the used steam condenses from the turbine back into re-usable water.