The LM2500+G4 marine gas turbine is the 4th generation of the LM2500 marine gas turbine. Its main features are increased power (17%) compared to the the 3rd generation LM2500+, the same high availability and reliability and the same high efficiency.
The increase in power is derived from a combination of a 6% increase in airflow, higher exhaust gas temperatures and a higher pressure ratio, 24.2 vs 23.6:1. This was achieved by incorporating the following proven technology enhancements:
- Redesigned inlet guide vanes and re-staggered stage 0 blisk airfoils.
- Increased high-pressure component life through changes in materials.
- Redesigned stage one high-pressure turbine blade with improved cooling and oxidation coating.
- Application of thermal barrier coatings to high-pressure turbine stage one nozzle.
- Material change and improved cooling for the stage two nozzle.
- Redesigned stage two high-pressure turbine rotor for increased life.
- Redesigned stages two and three nozzles of the 6-stage power turbine for increased power output.
The LM2500+G4 marine gas turbine can be housed in a highly-shock-resistant, thermal, acoustic enclosure on a mounting base. The enclosure attenuates noise in the engine room and provides sensors for inlet icing and fire detection. It also houses fire extinguishing equipment. Modules for this new engine will require modifications to the LM2500+ module.
The simple modular design of the LM2500+G4 incorporates many features to maximize shipboard maintainability and parts replacement downtime, such as a split compressor casing, in-place blade and vane replacement, in-place hot section maintenance and accessible external fuel nozzles.