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.
Why extractions are taken out from steam turbine.
The purpose of exhaust hood spray is to decrease the temperature of steam turbine last stage that is probably LP. This is operate on low load specially at start up and shut down of steam turbine when the temperature at the outer most edge of the turbine blades of that stage is very high and As we know that the steam flow also decrease The temperature of turbine blade.
Rankine cycle is used in steam turbine
Steam turbine nozzle clearance is the total energy content available in steam. This is through a valve.
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.
Why extractions are taken out from steam turbine.
The purpose of exhaust hood spray is to decrease the temperature of steam turbine last stage that is probably LP. This is operate on low load specially at start up and shut down of steam turbine when the temperature at the outer most edge of the turbine blades of that stage is very high and As we know that the steam flow also decrease The temperature of turbine blade.
You don't start a large turbine cold. Typically, the lubrication system is started, the turning gear is engaged and warming steam (a small amount of steam, not enough to turn the turbine) is admitted to the turbine to warm and initially expand the shaft and casing. If this isn't done, thermal shock from the admission of high pressure superheated steam into the cold turbine could damage it.
Steam is redirected back into the boiler from the high-pressure turbine for reheating, but the steam from the low-pressure turbine enters into a condenser to become water again.
The preventive maintenance of steam turbine mainly entails frequent servicing of the parts. This will ensure a smooth performance of the steam turbine.
manish
Rankine cycle is used in steam turbine
To avoid slugging nozzles and blades inside the turbine with condensate on start-up; this can break these components from impact. The blades were designed to handle steam, not water.
why we are maintain vacuum in steam turbine at steam outlet or exhaust side
Steam turbine nozzle clearance is the total energy content available in steam. This is through a valve.
inconsistent load will cause steam turbine hunting.