Altitude Performance Test Results for Low Pressure Turbine Mounted Generator 2006-01-3056
Aircraft generators are usually installed on an engine-mounted gearbox pad. In this type of installation, the speed range can be adjusted to match available generator speeds, and the installation environment is not as harsh as the engine operating environment. On the other hand, mounting the generator directly to the engine main shaft provides significant advantages, such as eliminating the generator gearbox pad, yielding major weight and cost savings. Furthermore, the low-pressure turbine spool might have excess power that could be used to power the generator, thus enhancing the overall engine performance.
The obvious disadvantage is the hot environment inside the tail cone, which can exceed 700°F. In this installation, heat transfers to the generator by convection from the surrounding air, conduction through the mounting interface, and radiation from the 1200°F tail cone.
IPS has now completed the development and testing of a low pressure spool turbine generator (LPT Generator) directly mounted to the engine in a tail cone installation. The generator has been successfully tested on the engine at altitudes from sea level to 65,000 feet. Analytical predictions have been correlated to the test results. Additionally, a substantial amount of lessons learned were achieved through the development and testing process.
This paper is a continuation of paper titled “Generator Survivability in the Hot Environment Associated with Low Pressure Turbine Installation, SAE Document Number: 2004-01-3155”. The benefits, technical challenges and preliminary results are discussed in the 2004 paper. This paper will cover the analysis and test results that have been obtained since 2004.