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Home | Update | Latest Issue | Gallery | FR Profile | Datafiles | FR 7/97 MTU SETS NEW STANDARDS FOR LOW PRESSURE TURBINES by Dr. Reinhard Niehuis / Dr. Klaus-Peter Rüd MTU München has come another step closer to its goal of developing more economical and environmental-friendly engines. During test runs, at the high altitude test bench of the University of Stuttgart, at the beginning of this year, the fast-turning transonic low-pressure turbine of the ADP demonstrator engine showed an efficiency which set new technological standards in the international comparison. MTU's three-stage transonic low-pressure turbine had already accomplished successful runs in the ADP demonstrator engine (Advanced Ducted Propfan) which was built together with FiatAvio and Pratt & Whitney, then driving the fan. The main goal of this first engine test was to prove the functionality of the propfan propulsion concept in extremely high bypass conditions, designed for a higher economic efficiency and environmental friendliness of future engines. Then, the noise emission of the new propulsion concept was measured, also proving that a variable propfan can generate enough reverse thrust. Since ground test-runs were sufficient for these tests, the MTU low-pressure turbine was at that time not tested under design/flight conditions. While the basic function and strength of the low-pressure turbine was proven, an exact and reliable efficiency measurement was still needed. Only in the frame of the Engine 3E technology program was it now possible to measure the ADP turbine with aerodynamical precision. The program "environmental friendly propulsion engine 3E" is part of the German government funded aerospace research program. The fast-turning transonic low-pressure turbine is a key component of the 3E program. In January of this year, extensive component tests with the ADP low-pressure turbine were successfully accomplished at the high-altitude test bench of the University of Stuttgart. Although the MTU low-pressure turbine, as compared to conventional turbines, features a drastically reduced number of stages, is fast turning, and has transonic flow characteristics, it achieved the same specific efficiency which so far was the domain of the world's best conventional low-pressure turbines. The MTU low-pressure turbine was fitted with extensive and modern instrumentation for the high-altitude test bench trials. Also, a new water brake system had to be installed in the test bench to cope with the high performance output and rpm of the ADP low-pressure turbine. Along with the exact measurement of the efficiency and the charcteristics, it was also possible to record detailed data of the turbine's 3-D flow field. The gathered data significantly expanded the understanding of the aerodynamics and acoustics of fast-turning transonic turbines, generating an important basis for the calibration of new 3-D designs. This know-how is now being used to achieve the further expansion of the efficiency. Parallel to these measurements in the altitude test bench, MTU has already made the next steps towards fast-turning transonic low-pressure turbines. The ADP demonstrator will continue to be used as a technology bench but will be equipped with new blades which are already designed according to the newest findings of aerodynamics, acoustics and strength. With the new blades, higher pressure rations and higher aerodynamical loads will be possible. Furthermore, the more stringent fatigue and life-time requirements will be fulfilled which have been acquired as standards from the most recent engine studies and market analyses. MTU's aim is to pick up the testing of the new low-pressure turbine by the end of 1997. From page 58 of FLUG REVUE 7/97 Home | Update | Latest Issue | Gallery | FR Profile | Datafiles | FR 7/97 Copyright 1997 by Motor-Presse Stuttgart. All rights reserved. Last updated June 4, 1997