Gas Turbines Flashcards
What is the function of a Gas Turbine on board?
To convert heat energy to rotary motion for ship’s propulsion
What is IEP
Integrated Electric Propulsion
What is CODLAG
Combination of Diesel, Electric and Gas
What are the advantages of Gas Turbines?
Ability to get underway quickly
High power/weight ratio
Minimum shipboard maintenance
Low manpower requirement
Describe the 3-stage air filter system
1st stage - SPRAY ELIMINATOR- air changes direction because of the baffle plates, this causes water held in suspension to drop and fall to the water trough
2nd Stage- KNITMESH FILTER- air passes through this filter removing any particulate matter
3rrd stage- water drains into a water trough, any excess water drains away by the manometric leg which maintains the water level, a water seal across the bottom of the filter prevent unfiltered air from getting through
What is the function of the Splitter/Silencer?
Smooths out the airflow removing turbulence, air noise and buffeting
What is the purpose of the stone guard?
Prevents large particles of debris from entering the gas turbine during maintenance
What is the function of the Cascade bend?
Lets the air travel through smoothly at a 90 -degree bend
What is the purpose of the engine intake flare?
houses the water wash rings and seals of the engine intake from the rest of the module
Describe the module Ventilation System
Air is drawn into the module caused by the depression formed at the other end Air circulates the module keeping it cool A depression of air is formed by the rushing of exhaust gasses (bernoulli's principle)
What component provides drive into the gear box?
power turbine
Explain how the compressors are driven
Explain the air flow through a gas turbine
What oil is used to lubricate a gas turbine?
OX22 lub oil
Why are Mag Chips fitted and how often are they checked?
For early failure detection, they are inspected every 24 -running hour
list the safety devices fitted to a gas turbine
hand trip fire detectors partial over speed low pressure and high pressure governors safety interlocks vibration monitors
Describe partial over speed
If the propeller comes out of the water, this reduces the amount of fuel to the engine preventing it from over speeding
Describe power turbine over speed
if the power turbine exceeds 110% maximum speed the engine will shut down
what hazards are associated with igniters
electric shock as it can produce volts up to 2000
what hazards are associated with gas turbines
noise - it can get very loud
whose permission is needed to enter a gas turbine module?
MEO- Marine Engineering Officer
What firefighting systems are fitted to a gas turbine module?
the drenching sytem
what are the dangers of module fire suspension systems?
it is very toxic
What running checks are carried out on a gas turbine?
Pressure & Temperature, oil levels, noise and vibration, leaks
what is a wet motor and when would it be performed?
wet motoring is turning over an engine using the starter motor and the fuel on that us supplied to the combustion cans
it is performed after maintenance
what is dry motor and when can it be performed?
turning over the engine using the starter motor and the fuel and igniters are isolated
how often is water washing performed?
for a WR21 150 running hours
Spey 100 hours or 2 months
or
when the engine deteriorates
Draw and label a gas turbine intake system
draw and label a module ventilation system
draw and label a gas turbine engine
draw and label a combustion can
