The WR-21 is the first production aero-derivative gas turbine to incorporate compressor inter-cooling and exhaust heat recuperation technologies that deliver low specific fuel consumption across the engines entire operating range. The 25MW WR-21 has a footprint is no larger than current simple cycle marine gas turbines and offers a 25-27 per cent fuel saving.
Reliable components from current Rolls-Royce RB211 and Trent engines are at the core of the truly modular WR-21, designed for ease of maintenance and reduced through life costs.
The gas generator and power turbine consists of 12 interchangeable pre-balanced modules. Because of their size and low weight, these modules can be removed and new modules can be fitted to reduce maintenance costs and down time.
The WR-21 engine incorporates revolutionary enhancements in gas turbine technology to reshape the traditional gas turbine performance curves and produce long term fuel savings.
The intercooler, located between the compressor sections, cools the intermediate-pressure compressor (IPC) air before it enters the high-pressure compressor (HPC). This reduces the HPC inlet temperature and therefore HPC work to deliver a significant boost in engine power. The intercooler also enhances recuperator effectiveness, as the inlet temperature is reduced thereby increasing exhaust heat recovery.
The recuperator recovers and transfers heat energy from the hot exhaust, which is used to preheat combustion air, therefore much less fuel is required to reach the same power turbine entry temperature (PTET). As a result less fuel is used to achieve the same power. Recovering heat energy from the exhaust gas also reduces its temperature giving a reduced infrared (IR) signature.
Variable area nozzles (VAN) located at the entrance to the power turbine, open and close on command to control the air mass flow rate through the engine. This provides a means to manage and optimise the PTET and subsequently the exhaust gas temperature into the recuperator, optimising fuel efficiency across the power range, and particularly at partial load.
Rolls-Royce gas turbines are supported worldwide by the Rolls-Royce global service network. A range of tailored maintenance packages are available to drive down through life costs.
(Top - Type 45 images courtesy BAE Systems)