Machinery Control System and Gas Turbines Overview

Machinery Control System (MCS)

• DDG-51 class uses aircraft derivative gas turbines for propulsion and electrical power generation
• Plant automation controlled by MCS
• MCS uses Gigabit Ethernet Data Multiplex System (GEDMS) for communication between Engineering Plant user controls (e.g., Bridge, CIC)
• Universal Control Consoles (UCC) can function in various roles, including Central Control Single Watchstander (CCSW), Propulsion Auxiliary Control Console (PACC), Electrical Plant Control Console (EPCC), and Shaft Control Units (SCU1/2)
• Four UCCs exist, two in Central Control Station (CCS), one in Machinery Error Room 1 (MER1), and one in MER2
• All UCCs are interchangeable and perform the same functions

Gas Turbine Module (GTM)

• Four GTMs on USS Ralph Johnson, two per main engine room
• GTM enclosures support, cool, reduce airborne noise, and provide fire protection for the turbines
• GTMs are resiliently mounted to reduce structure-borne noise and vibration shock
• Two GTMs in each Main Engine Room (MER) are protected by a primary and reserve Halon 1301 fire extinguishing system

LM2500 Gas Turbine Engine (GTE)

• General Electric LM 2500 produces 26,250 horsepower
• GTE consists of a gas generator (compressor), combustor, and high-pressure and power turbines
• Compressor increases ambient air pressure to approximately 130-150 psi
• Combustor ignites fuel/air mixture to create thermal energy
• High-pressure turbine extracts thermal energy, converting it into mechanical energy to rotate the compressor and accessories
• Power turbine converts remaining energy into mechanical energy to rotate the main shaft

Intake System

• Furnishes ambient air from outside the ship to each GTM
• Includes louvers, air filters, blow-in doors, silencers, and an inlet plenum with a foreign object debris (FOD) screen
• Provides cooling air to the GTM
• Cooling air is extracted through the intake system through a cooling fan

Fire Detection and Extinguishing System

• Temperature sensors and flame detectors
• Temperature sensors trigger an alarm at 450+-10 degrees
• Flame detectors detect UV light from a fire
• System activates automatic fire stop for the engine.
• Halon discharge nozzles and two Halon bottles for extinguishing fire
• One is for primary and one for reserve

Engine Controller (EC)

• High-performance computer-based controller for the LM2500 engine
• Controls all inputs and outputs from the engine
• Each engine has its own EC essentially the brain of the engine

Lubrication Oil Storage/Conditioning Assembly (LOSCA)

• Consists of an oil tank with approximately 19 gallons of synthetic lubricant oil 23699
• Has a duplex scavenge filter and heat exchanger which uses the ship's reduction gear lube oil as a cooling medium for the oil

Fuel Oil Service System

• Supplies clean, filtered, and water-free fuel to propulsion and generator turbines
• Uses MIL-F-16884 (NATO F-76) or JP-5 (NATO F-44)
• System includes:
  • 4 fuel oil service tanks
  • 2 gravity feed tanks
  • 1 fuel head tank for 3GTG
  • motor operator service and return valves
  • emergency quick closing fuel valves
  • various numbers of motor-operated fuel pumps, electric fuel heaters, pre-filters, and separators.
  • Fuel unloading valves

Fuel Transfer System

• Primary storage provided by 25 structural fuel tanks divided into six tank groups
• Each group has receiving tanks, storage tanks, and expansion/overflow tanks.
• Transfer systems consist of a pump, purifier, and heater
• These fuel tanks are seawater compensated to maintain equilibrium of the ship

JP-5 Transfer and Service System

• Normal fuel source for ship's helicopters
• Also used in emergencies for GTMs and GTGs
• System consists of:
  • Aircraft refueling hose, transfer pump, service pump, transfer and service filters, stripping pump
  • storage and service tanks (including one with a service pump)
  • Additive di-ethylene-glycol-monomethyl-ether (DiEGME) for preventing freezing in extreme altitudes