Centennial College - SDRE: ESET 223 15 Lubrication Systems Gravity-Fed

In which type of turbine is the kinetic energy of steam (impulse force) used to rotate the turbine?

Steam turbine
Impulse turbine (correct)
Combined turbine
Reaction turbine

What type of force is used to rotate the turbine in an impulse turbine?

Reaction force
Impulsive force (correct)
Kinetic force
Pressure force

What is the basis of difference between impulse and reaction turbines?

Direction of steam flow
Number of blades
Type of steam used
Force used to turn the turbine (correct)

What is the function of guide blades in a reaction turbine?

To guide steam flow over the turbine (A) Signup and view all the answers

What happens to the pressure of steam in an impulse turbine while flowing over moving blades?

It remains unchanged (A) Signup and view all the answers

What happens to the pressure of steam in a reaction turbine while flowing over the blades?

It decreases continuously (A) Signup and view all the answers

In which type of turbine does the pressure of steam decrease in the nozzle before entering the turbine?

Impulse turbine (C) Signup and view all the answers

What type of energy of steam is used to turn the turbine in a reaction turbine?

Pressure energy (B) Signup and view all the answers

In an impulse turbine, how is the steam guided to flow over the turbine?

Through a nozzle (C) Signup and view all the answers

What type of force on the blades rotates the turbine in a reaction turbine?

Reaction force (A) Signup and view all the answers

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 (C) Signup and view all the answers

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 (A) Signup and view all the answers

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 (C) Signup and view all the answers

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 (B) Signup and view all the answers

What distinguishes a condensing steam turbine from a noncondensing steam turbine?

The presence of a condenser and giant concrete cooling towers (C) Signup and view all the answers

Why must noncondensing steam turbines use a large amount of the available exhaust steam to maintain maximum efficiency?

To prevent condensation of the steam (D) Signup and view all the answers

What is the significance of an increase in vacuum on the exhaust of a steam turbine?

It increases the efficiency of the turbine (A) Signup and view all the answers

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 (A) Signup and view all the answers

What is a characteristic of noncondensing steam turbines?

They have no condensate returns (B) Signup and view all the answers

What distinguishes condensing turbines from noncondensing turbines?

The presence of a condenser and giant concrete cooling towers (B) Signup and view all the answers

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 (C) Signup and view all the answers

What is the purpose of the centrifuge in force-fed lubrication systems for steam turbines?

To remove dirt and water from the lubricating oil (C) Signup and view all the answers

What role does a mechanical governor play in steam turbines?

Maintaining a constant speed of rotation for the steam turbine (C) Signup and view all the answers

Which type of steam turbine exhausts at atmospheric pressure or above?

Noncondensing steam turbine (A) Signup and view all the answers

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 (B) Signup and view all the answers

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 (D) Signup and view all the answers

What happens if the centrifugal force exceeds the centripetal force in a steam turbine?

The turbine will self-destruct (A) Signup and view all the answers

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 (B) Signup and view all the answers

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 (B) Signup and view all the answers

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 (A) Signup and view all the answers

In an impulse turbine, what converts the pressure of steam into kinetic energy?

Nozzles attached to the casing (B) Signup and view all the answers

Why is the speed of reaction turbine much lower than that of an impulse turbine?

Steam velocity is lower in reaction turbine (C) Signup and view all the answers

What is the purpose of the fixed blades in a reaction turbine?

To convert steam pressure into kinetic energy (B) Signup and view all the answers

What type of steam turbine is used in plants where there is an abundance of low-pressure steam?

Mixed-pressure steam turbine (A) Signup and view all the answers

What is the purpose of a double-flow steam turbine?

To balance the axial thrust on the rotor (C) Signup and view all the answers

What is the function of extraction steam turbines?

To use steam withdrawn from a stage of the turbine for process or feedwater heating (D) Signup and view all the answers

Why is the proper lubricating oil essential for steam turbine operation?

To prevent wear from friction on the turbine rotor (A) Signup and view all the answers

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 (C) Signup and view all the answers