July 19, 2013
The NASA Aeronautics Academy had the fortune of presenting their team projects to GE Aviation as well as touring some of GE’s research labs in Cincinnati, Ohio. The first lab that the Academy toured was the Low Speed Compressor Lab and our tour guide was Dr. Hyoun Woo. This lab is over 50 years old and has been doing state of the art research to enhance the efficiency of compressors. In order to test compressors and see changes in efficiencies, GE needed to scale up the size of the airfoils of the rotors and the stators. With an increase in airfoil size the lab needed to decrease the speed at which the rotors turned to compensate for an increase in Reynolds number, hence the name, Low Speed Compressor. With a large scale model of a compressor, GE has been able to do research on the aerodynamics of the flow around the rotor and stator blades as well as temperature and pressure measurements. One specific experiment was to determine when the engine will stall. Engine stall is a very big safety concern in the airline industry as it effectively stalls the aircraft and the consequences can be catastrophic. GE has done experiments where they have stalled the engine to determine the stall margin but they want to be able to determine the stall margin without stalling the engine. This is currently being investigated. The Low Speed Compressor Lab has also done work with the unducted fan engine. This novel design concept showcases two sets of counter rotating fans that are not enclosed with a fan casing. The unducted fan design significantly reduced fuel consumption but there were issues with mounting the engine onto existing aircraft. Before this issue was resolved, the unducted fan project was cancelled due to a sudden drop in oil price. However, the research that enabled prototypes of the fan blades went a long way and ended up being used in GE’s most powerful engine, the GE90. This shows that while a project may be cut or cancelled, the research is always fruitful and beneficial.
The second lab that the Aeronautics Academy visited was the Combustion Test Lab. This lab looked into analyzing the combustor component of the engine. The lab has two test cells and is building two more combustor test cells which will have higher temperature and pressure capabilities. The test cells are built into a pressure house and to run one experiment, the test cell requires two times more electrical power to pump up to a specified pressure than the rest of the GE Aviation facility needs. To run one experiment, a variety of calculations and preparation needs to be done to set the inputs for a test. Also, since the sensors are recording real time data, a large and powerful storage system is needed to store and process the data.
The last lab was a tour of the different engines that GE has developed over the years. Numerous amounts of engines were displayed on stand or hanging from the ceiling in the Learning Center where the academy members gave their team presentations. An employee in the Learning Center gave an overview of each engine. While most of the engines were amazing, the GE90 model was the main attraction. The size of the engine was enormous with a 10.5 foot diameter, it is the largest GE engine to date producing the most thrust at 120,000 pounds! Because of the size, GE is proud to hold the Guinness record of building the largest jet engine in the world. This was the last tour and ended a very successful and informative visit to GE Aviation. The Aeronautics Academy left a very good impression with the Academy!