Institute of Flight Propulsion

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Institute of Flight Propulsion Experimental investigation and numerical simulation of flight propulsion systems and turbomachinery components n Research activities of the Institute of Flight

Based on a long tradition the institute develops thermo-dynamic engine models in order to investigate steady and unsteady gas turbine engine and turbomachinery behavior. Prof. Dr.-Ing. Oskar J.

1 Institute of Flight Propulsion Experimental investigation and numerical simulation of flight propulsion systems and turbomachinery components n Research activities of the Institute of Flight Propulsion in 2015 covered topics in the fields of flight propulsion, gas turbines and thermal turbomachinery. Based on a long tradition the institute develops thermo-dynamic engine models in order to investigate steady and unsteady gas turbine engine and turbomachinery behavior. Prof. Dr.-Ing. Oskar J. Haidn (Acting Head) Contact sekretariat@lfa.mw.tum.de Phone The history of the Institute of Flight Propulsion (LFA) reaches back until 1964, when Prof. Münzberg was first appointed to the head of the chair in downtown Munich. Since its foundation the institute has been dedicated to research and teaching in the field of jet propulsion and gas turbines. The institute is an active member of national research associations, participant in European research projects and long-term partner of leading aero-engine and component manufactures. One Compressor Aerodynamics, Performance and Operating Range Extension highlight is the framework agreement between the Institute of Flight Propulsion/ TUM, the Bavarian Government and GE Global Research Europe. The cooperation includes the development of the world s most advanced high speed research radial and axial compressor laboratories focused on developing tomorrow s aircraft engines and gas turbines. End of 2015 the first test vehicle for the new axial compressor testbed arrived at Garching and the commissioning of the entire rig already started. The achievement of a high level of efficiency in combination with the guarantee of aerodynamic stability is a main objective in the design of highly loaded compressors. Since the stability margin drops critically with increasing stage loading and transient operation, identifying and understanding the mechanisms for stall inception is the key to increase the range of stable operation. Unsteady flow simulations are applied to investigate the phenomena inherent to the development of aerodynamic instabilities. For an investigated centrifugal compressor, the impact of newly designed and circumferentially non-uniform inlet guide vanes is studied. The simulation results are validated against measurement data currently acquired from the institute s high speed centrifugal compressor test rig. Furthermore, casing treatments for multistage axial compressors are designed numerically to passively extend the stable operating range. Tip blowing casing treatment applied to an axial compressor including streamlines The unsteady interaction between main flow and the exiting and re-entering treatment flow is investigated using state of the art phase lag simulations. Experimental validation is performed in close cooperation with associated national research institutes and industry partners. 118 Institute of Flight Propulsion

Computational Aeroacoustics for Ducted and Unducted Turbomachinery Growing environmental awareness raises demand for highly-efficient and low noise emitting turbomachinery, guaranteeing stable

In order to improve state-of-the-art turbomachinery, methods for direct and hybrid sound prediction are devolved and applied in combination with high-fidelity computational fluid dynamics analyses.

2 Computational Aeroacoustics for Ducted and Unducted Turbomachinery Growing environmental awareness raises demand for highly-efficient and low noise emitting turbomachinery, guaranteeing stable operation under a large range of operating conditions. In order to improve state-of-the-art turbomachinery, methods for direct and hybrid sound prediction are devolved and applied in combination with high-fidelity computational fluid dynamics analyses. Based on time-resolved simulations of the flow field, deterministic and nondeterministic sources for aerodynamically generated sound can be identified to deduce avenues for passively reducing noise. The radiated sound field is then determined by extrapolating the flow field data into the acoustic farfield by means of in-house acoustic solvers. Due to the high computational effort involved in combined aero and acoustic predictions, present research activities aim at developing low order models for predicting sound from propellers and open rotors. Consequently, lower turn-around times for design iterations can be achieved, thus offering possibilities for automated aeroacoustic optimizations and acoustic inverse design of turbomachinery. Methodology for hybrid acoustic predictions relying on high fidelity flow field simulations and in-house sound extrapolation routines Supersonic Combustion Research for Scramjet Applications A scramjet (supersonic combustion ramjet) is a future air breathing propulsion concept for high speed vehicles traveling faster than Mach 5. It is one of the most promising propulsion concepts for future space transportation systems and hypersonic flight vehicles. Despite decades of research in this area, scramjets still offer several unresolved challenges. To achieve an air breathing hypersonic flight one of the key technologies is supersonic combustion. At these speeds, the residence time of air inside the engine is of the order of milliseconds. Therefore, mixing and reaction processes in the combustor must be efficient and very fast. The internal flow of a scramjet combustor is studied in a supersonic combustion test bed at the Institute of Flight Propulsion. Current research topics are related to improving combustion stability, reducing auto-ignition temperatures and increasing combustor efficiency using catalytic radical farming and the investigation of the non-reacting and reacting internal flow phenomena using optical measurement techniques. Supersonic combustion test bed at the Institute of Flight Propulsion Institute of Flight Propulsion 119

Compact Turboshaft Engine Quick-Start System for Rotorcraft Applications Turboshaft engine testbed Current helicopters of the light and medium class have two engines installed due to safety reasons.

An operational strategy during flight can be an intended shutdown of one engine.

3 Compact Turboshaft Engine Quick-Start System for Rotorcraft Applications Turboshaft engine testbed Current helicopters of the light and medium class have two engines installed due to safety reasons. However, this installed power is rarely needed during a flight mission and the engines are operating mainly in part load, leading to poor specific fuel consumption. An operational strategy during flight can be an intended shutdown of one engine. The required power is then covered by the remaining engine which thus runs at higher loads at enhanced specific fuel consumption. Therewith, fuel can be saved, the mission range can be enhanced and emissions can be reduced. In case of a failure of the remaining running engine, the shut-off engine has to be quick-start capable due to flight safety reasons. Quantification of the fuel savings is a focal point of research on intended single engine operation. Since this engine usage strategy is limited to certain areas of the helicopter flight envelope, flight performance analysis of the helicopter has to be performed in advance. Then, realistic flight missions are chosen for subsequent flight mission simulation and evaluation regarding a useful operational strategy. For realization of engine quick-starts a new system was developed and evaluated at the turboshaft engine testbed. Its working principle is based on air injection through Laval nozzles inside the compressor section. Therewith, a significant start-up time reduction can be achieved. Since shop air is actually used for the quick-start system, an additional system is designed for independent air supply and for integration into a helicopter airframe. For further investigation of the influence on the helicopter drive powertrain, the testbed engine was successfully coupled with the research simulator of the Institute for Helicopter Technology. Structural Design and Optimization of Aircraft Engine Components Stress distribution in a generic disk a) without and b) with heat pipe A higher turbine inlet temperature and the reduction of component weight are key parameters for a better overall efficiency of future propulsion systems. This requires new design concepts for turbine components. The new design should meet or exceed the reliability requirements of conventional designs. For their lifespan, the dimensioning damage mechanisms of turbine components are long-term creep and thermo-mechanical fatigue. To meet these requirements, two design concepts are investigated. On the one hand, additive manufacturing (AM) technologies enable novel light weight structures. Using the finite element method (FEM), a new design method for additively manufactured turbine guide vanes with reduced weight and unchanged functionality and life span is investigated. On the other hand, in order to cool and reduce the maximum material temperature at the rim of turbine disks, the use of high temperature heat pipes inserted into the disk material is investigated. 120 Institute of Flight Propulsion

Centrifugal Compressor Test Rig Centrifugal compressor test rig In the year 2010 a new high-speed radial compressor test rig was commissioned in cooperation with GE Global Research.

4 Centrifugal Compressor Test Rig Centrifugal compressor test rig In the year 2010 a new high-speed radial compressor test rig was commissioned in cooperation with GE Global Research. The latter meets the industrial standards for design & testing and enables experimental testing of different types of modern centrifugal compressors with drive power up to 800 kw and a maximum speed of 30,000 rpm. The test facility can be operated either in open-loop or closed-loop configuration. The research activity focuses on the optimization of centrifugal stage components and their mutual interactions in terms of efficiency and operation range. Research topics like operation range expansion by flow control, impact of impeller surface roughness, performance validation of 3D industrial compressor design and variable inlet guide vanes (IGVs) have been conducted. LFA will continuously expand its research capacity in the area of centrifugal compressors to achieve in-depth understanding of the following topics: n Performance characteristics of shrouded and unshrouded impellers with applications in petrochemical industries and aviation businesses n Testing of various inlet configuration possibilities n Implementation of advanced diffusion systems (with low diffuser ratios, new return channel vanes, etc.) n Numerical investigations in parallel to experimental studies The project is funded by the Bavarian Ministry of Economic Affairs and GE Global Research in Garching, in collaboration with GE Oil & Gas and GE Aviation. Competence n Numerical and experimental investigation in gas turbines and turbomachinery components n Gas turbine performance simulation n Fluid dynamics and structural mechanics of turbomachinery components Infrastructure n Helicopter engine testbed n Test rig for centrifugal compressors n Test rig for axial compressor (under construction) n Subsonic and supersonic combustion testbed n Testbeds for very small gas turbine engines n Institute s own computer cluster with more than 350 cores Courses n Flight Propulsion I & II n Turbomachinery (Basic and Advanced) n Mechanical Design of Jet Engines n Aerodynamic Design of Turbomachinery n Application of Fluidmechanic Calculation Methods for Flight Propulsion n FEM and CFD Design of Turbomachinery Institute of Flight Propulsion 121

5 Management Prof. Dr.-Ing. Oskar J. Haidn (Acting Head) Dr.-Ing. Wolfgang Erhard Dr.-Ing. Andreas Hupfer Adjunct Professors Prof. Dr.-Ing. Hanns-Jürgen Lichtfuß Dr.-Ing. Jörg Henne, MTU Aero Engines Prof. Dr.-Ing. Hans Rick Prof. Dr.-Ing. Dieter Rist Prof. Dr.-Ing. Dr. h.c. mult. Günter Kappler Administrative Staff Karin Engels Angelika Heininger Research Scientists Nan Chen, M.Sc. Dipl.-Ing. Florian Danner Dipl.-Ing. Sina Eisenmann Andreas Feierabend, M.Sc. Fabian Fuchs, M.Sc. Dipl.-Ing. Michael Gurtner Dipl.-Ing. Cyril Guinet André Inzenhofer, M.Sc. Christofer Kendall-Torry, M.Sc. Dipl.-Ing. Martin Kerler Daria Kolmakova, M.Sc. Dipl.-Ing. (FH) Sebastian Lang, M.Sc. Dipl.-Ing. Daniel Paukner Dipl.-Ing. Marcel Schmieder Joona Seppälä, M.Sc. Chengyu Zhang, M.Sc. Technical Staff Zoe Gerstung Roland Grubert Ralf Priller Publications 2015 n Sina Eisenmann, Alessandro Primavera, Andreas Hupfer: Analysis of a Gas Turbine Disk Incorporating Radially Rotating Heat Pipes with a Focus on Stress Concentrations, ISABE , 22nd ISABE Conference, International Society for Airbreathing Engines, Phoenix, USA, 2015 n Martin Kerler, Johannes Elfner, Wolfgang Erhard: Investigation of Engine Operating Behavior after Compressor Casing Modification due to Installation of a Quick-Start System, ISABE , 22nd ISABE Conference, International Society for Airbreathing Engines, Phoenix, USA, 2015 n Nan Chen: Numerical Investigation of a Centrifugal Compressor with Inlet Distortions Induced by Variable Guide Vanes A Comparison between Steady, Transient and Transient Blade Row Simulation Methods, ANSYS Conference & 33rd CADFEM Users Meeting 2015, June 24-26, 2015, Bremen, Germany n Ismail Sezal, Matthias Lang, Christian Aalburg, Nan Chen, Wolfgang Erhard, Alberto Scotti Del Greco, Libero Tapinassi and Rajesh Kumar V. Gadamsetty: Introduction of Circumferentially Non-Uniform Variable Guide Vanes in the Inlet Plenum of a Centrifugal Compressor for Minimum Losses and Flow, GT , ASME Turbo Expo 2015: Turbine Technical Conference and Exposition, Volume 2C: Turbomachinery, Montreal, Quebec, Canada, 2015, ISBN: n Sina Eisenmann, Roman Körner and Andreas Hupfer: Transient Simulation of a Gas Turbine Disk Incorporating Heat Pipes Under Structural Aspects, Paper No. GT , ASME Turbo Expo 2015: Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, 2015, ISBN: n Cyril Guinet, André Inzenhofer and Volker Gümmer: Influencing Parameters of a Tip Blowing Interacting with Rotor Tip Flow, GT , ASME Turbo Expo 2015: Turbine Technical Conference and Exposition, Volume 2A: Turbomachinery, Montreal, Quebec, Canada, 2015, ISBN: n Martin Kerler, Christian Schäffer, Wolfgang Erhard: Design of an Engine Quickstart System for Rotorcraft Application, Paper ETC , 11th European Turbomachinery Conference, Madrid, Spain, 2015 n André Inzenhofer, Andreas Hupfer, Cyril Guinet, Henner Schrapp, and Volker Gümmer: Influence of a Tip Blowing Casing Treatment on the Stator Flow, 51st AIAA/SAE/ASEE Joint Propulsion Conference, Propulsion and Energy Forum, (AIAA ), 2015 n D. Rahn, R. Schmidt, F. Greif, A. Hupfer: Untersuchungen zu Düsenströmungen kleiner Fluggasturbinen, Deutsche Gesellschaft für Luft- und Raumfahrt Lilienthal-Oberth e.v., Deutscher Luft- und Raumfahrtkongress 2015, Rostock; URN: urn:nbn:de:101: n Nan Chen, Wolfgang Erhard: Numerical Investigation of a Centrifugal Compressor Stage with IGV Induced Inlet Flow Distortions, Conference on Modelling Fluid Flow, 16th International Conference on Fluid Flow Technologies, Budapest, Hungary, September 01-04, Institute of Flight Propulsion

Engineering Success by Application of Star-CCM+ for Modern Gas Turbine Design

March 18 th, 2014, Vienna, Austria STAR Global Conference Engineering Success by Application of Star-CCM+ for Modern Gas Turbine Design Karsten Kusterer B&B-AGEMA GmbH, Aachen, Germany Ryozo Tanaka Kawasaki