The LM2500 marine gas turbine is a simple cycle, two-shaft engine derived from GE’s TF39 and CF6-6 aircraft engines.
A third issue facing gas turbines in naval applications is that of Foreign Object Damage (FOD).
The LM2500 and LM6000 gas turbine employ a horizontal split casing. This enables it to be opened in-situ, and the blades can often be repaired or replaced in the ship. If the unit did not have this horizontal split casing, the turbine would have to be removed from the ship and sent off for repair, a costly process that could lay-up the ship for an extended period, especially if there is only one gas turbine.
The Royal Canadian Navy (RCN) has 24 LM2500 gas turbines in 12 Halifax-class frigates. Since 2001, GE has provided customised maintenance and logistic support services for this gas turbine fleet under a contract with Public Services and Procurement Canada. The contract has provided the RCN with many benefits, including an availability of the LM2500 fleet of 99.9 per cent over the 17 years of the contract.
The agreement with the Royal Canadian Navy includes:
Composite enclosure. Developed as a collaboration between the US Navy, General Dynamics Bath Iron Works and GE, it provides a 10 per cent power density improvement.
In addition, the Royal Australian Navy (RAN) has 28 LM2500 units on its Adelaide and Anzac-class frigates, and its two Landing Helicopter Dock ships HMAS Canberra and HMAS Adelaide. GE provides customised shipboard and depot-level maintenance for these turbines. In addition, the RAN’s new Hobart-class Air Warfare Destroyers (AWD) will also be powered by GE LM2500 gas turbines.
The depot-level maintenance is provided by Air New Zealand, an authorised LM2500 service centre and longtime RAN service provider.
LM2500 marine gas turbine
The LM2500 marine gas turbine is a simple cycle, two-shaft engine. It was derived from GE’s TF39 and CF6-6 aircraft engines.
The LM2500 has four major components: a 16-stage, 18:1 pressure ratio compressor with seven stages of variable stators and inlet guide vanes; a fully annular combustor with externally mounted fuel nozzles; a two-stage, aircooled high-pressure turbine which drives the compressor and the accessorydrive gearbox; and a six-stage, aerodynamically coupled, low-pressure turbine which is driven by the gas generator’s high-energy exhaust gas flow.
Shock testing involves mounting the gas turbine on a barge, which is then floated in a test pond. Then depth charges are detonated at set distances in the water, and the effect on the turbine measured.
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