38 Questions
In which type of turbine is the kinetic energy of steam (impulse force) used to rotate the turbine?
Impulse turbine
What type of force is used to rotate the turbine in an impulse turbine?
Impulsive force
What is the basis of difference between impulse and reaction turbines?
Force used to turn the turbine
What is the function of guide blades in a reaction turbine?
To guide steam flow over the turbine
What happens to the pressure of steam in an impulse turbine while flowing over moving blades?
It remains unchanged
What happens to the pressure of steam in a reaction turbine while flowing over the blades?
It decreases continuously
In which type of turbine does the pressure of steam decrease in the nozzle before entering the turbine?
Impulse turbine
What type of energy of steam is used to turn the turbine in a reaction turbine?
Pressure energy
In an impulse turbine, how is the steam guided to flow over the turbine?
Through a nozzle
What type of force on the blades rotates the turbine in a reaction turbine?
Reaction force
What is the main purpose of using a condensing steam turbine?
To turn the steam at least partly to water using condensers and giant concrete cooling towers
What would happen if the exhaust steam from a noncondensing steam turbine is allowed to go to waste into the atmosphere?
The thermal efficiency of the turbine would decrease
What is the role of a noncondensing steam turbine in heating water for a paper mill?
To use the exhaust steam to heat feedwater in an open feedwater heater
Why do condensing steam turbines operate with an exhaust pressure of 26" Hg to 29" Hg vacuum?
To allow the steam to expand more and extract more energy
What distinguishes a condensing steam turbine from a noncondensing steam turbine?
The presence of a condenser and giant concrete cooling towers
Why must noncondensing steam turbines use a large amount of the available exhaust steam to maintain maximum efficiency?
To prevent condensation of the steam
What is the significance of an increase in vacuum on the exhaust of a steam turbine?
It increases the efficiency of the turbine
What happens if a noncondensing steam turbine's exhaust steam is allowed to go to waste into the atmosphere?
The thermal efficiency of the turbine would decrease
What is a characteristic of noncondensing steam turbines?
They have no condensate returns
What distinguishes condensing turbines from noncondensing turbines?
The presence of a condenser and giant concrete cooling towers
In force-fed lubrication systems for large steam turbines, why must the lubricating oil be cooled?
To prevent the oil from breaking down and losing its lubricating ability
What is the purpose of the centrifuge in force-fed lubrication systems for steam turbines?
To remove dirt and water from the lubricating oil
What role does a mechanical governor play in steam turbines?
Maintaining a constant speed of rotation for the steam turbine
Which type of steam turbine exhausts at atmospheric pressure or above?
Noncondensing steam turbine
What is the function of a ring in gravity-fed lubrication systems for bearings on steam turbines?
To pick up oil and deposit it onto the shaft for bearing lubrication
Why must the lubricating oil coolers be periodically dismantled and cleaned in force-fed lubrication systems for steam turbines?
To remove scale and impurities from the tubes and shell
What happens if the centrifugal force exceeds the centripetal force in a steam turbine?
The turbine will self-destruct
What is the function of an overspeed trip device in a steam turbine?
To shut off the steam supply if the turbine exceeds its rated speed
What is the purpose of an adjustable spring in a mechanical overspeed trip mechanism for a steam turbine?
To hold a bolt in position until shaft speed overcomes its tension
What is the primary function of a hydraulic governor in a steam turbine?
To control and maintain a constant speed of rotation for the turbine
In an impulse turbine, what converts the pressure of steam into kinetic energy?
Nozzles attached to the casing
Why is the speed of reaction turbine much lower than that of an impulse turbine?
Steam velocity is lower in reaction turbine
What is the purpose of the fixed blades in a reaction turbine?
To convert steam pressure into kinetic energy
What type of steam turbine is used in plants where there is an abundance of low-pressure steam?
Mixed-pressure steam turbine
What is the purpose of a double-flow steam turbine?
To balance the axial thrust on the rotor
What is the function of extraction steam turbines?
To use steam withdrawn from a stage of the turbine for process or feedwater heating
Why is the proper lubricating oil essential for steam turbine operation?
To prevent wear from friction on the turbine rotor
What is the purpose of ring oilers in small auxiliary steam turbines?
To supply lubricating oil to bearing grooves for even distribution over bearing surfaces
Test your knowledge on gravity-fed lubrication systems used to feed lubricating oil to bearings on steam turbines. Learn about the mechanisms and components involved in this lubrication system.
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