32th Congress of the International Council of the Aeronautical Sciences

05 - Propulsion

INVESTIGATION OF VARIABLE GEOMETRIES ON THE OPERABILITY AND AIRCRAFT LEVEL PERFORMANCE OF A THREE-SHAFT TURBOFAN ENGINE FOR ENTRY INTO SERVICE 2050

D. Mo¹, Y.X. Liu¹, I. Roumeliotis², D. Nalianda²; ¹AECC Shenyang Engine Research Institute, China ;²Cranfield University, United Kingdom

The development of advanced propulsion systems has entailed complex and accurate fuel control strategy during transient operations. The application of variable geometry has proved to be an effective and practical approach for safety, energy, noise and emission reduction. This paper aims at exploring the influences of implementing variable geometry on a three-shaft turbofan engine performance, including variable inlet guide vanes (VIGV), blow-off valve (BOV) and bypass variable area nozzle (VAN). A dynamic model was established in Simcenter Amesim to provide the ability to assess the operability and aircraft level performance. The fan and compressor map, shaft speed, net thrust, specific fuel consumption (SFC), T4 as well as other critical parameters were investigated to observe the benefits of incorporating the mentioned devices. Results show that BOV opening would significantly mitigate the IPC surge issues by increasing the surge margin (SM) from 10% to 15%. However, the resulted loss in net thrust (FN) and SFC would reach 1.38% and 1.35% at take-off condition. The mission analysis also reveals that the over-open of BOV would consume 2.7% additional fuel. By contrast, a 10% of VAN expansion could better the SFC at take-off and block fuel by 8.62% and 2.41% respectively. Furthermore, T4 dropped by at least 26K if the bypass VAN went up by 10%. Meanwhile, the introduction of VIGV would not bother the engine performance but enlarge the core fan surge margin. Finally, exploiting the potential advantages of VIGV, BOV and VAN, a comprehensive control schedule was established to improve stability and save mission fuel.


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