Bastian Muth

Numerical Investigation of Inlet Induced Distortions of a Turbofan Engine Within an Indoor Test Facility

Future concepts for unmanned air vehicles or passenger aircrafts in blended wing body configuration often feature special fully integrated inlet geometries for the installed jet engines. In order to reduce drag, concepts are discussed to integrate the engines into the fuselage. Due to this unconventional air intake geometries are needed. At the Institute of Jet Propulsion of the University of the German Federal Armed Forces in Munich several jet engines are operated in an indoor test facility for educational as well as research purposes. This engine test bed offers the opportunity to perform basic experimental research on this topic. Different types of engines are available and were used for the numerical feasibility study presented herein. In order to estimate the possibility to operate one of these engines with an s-duct inlet attached numerical simulations of the facility had to be performed to get insight into the internal flow mechanisms. The Larzac 04 engine was chosen as test engine, because it is one of the present research vehicles and therefore features an extended instrumentation. Experimental data gathered during several test runs, performed with a bellmouth intake, have been used to validate the CFD results before simulating the s-shape geometry. The simulations with different s-ducts show the influence the inlet executes onto the inflow characteristics. Furthermore the investigations demonstrate the feasibility to run those ducts at the available engines in the test facility of the institute.

Experimental Investigations on Macro-Aerodynamics Within a Jet Engine Ground Test Facility

A series of ground test facilities is operated for science and pass off testing by research institutes and the various gas turbine engine manufactures. The different tasks entail a number of architectures, suitable for the specific requirements and characterized by parameters like the test cell cross sectional area or the engine thrust class. Despite these differences all test beds have to ensure homogeneous inflow conditions to operate the engine in a safe mode and to get most authentic test results. At the Institute of Jet Propulsion of the University of Federal Armed Forces in Munich several jet engines are operated in an indoor test facility for educational as well as research purposes. The special design of the facility, test cell in combination with a lecturing room, allows numerous visitors or students to participate in engine runs, but it also complicates the flow conditions in contrast to commercially used test beds. Exactly these aerodynamic parameters become more distinctive if the engine air mass flow is increased by installing jet engines of a higher thrust class. Simultaneous to the engine mass flow, also referred as primary mass flow, the mass flow rate through the entire test cell increases, due to the ejector effect at the detuner. Both facts lead to a higher test cell depression and therefore to higher loads onto the building itself and make it necessary to determine them. Studies presented within this publication deal with the macro-aerodynamic phenomena inside the test cell and measurement methods to quantify them accurately.

Basic Study of the Ejector Eect, Part 2: Experimantal Approach

Jet engine test facilities are used for various purposes throughout the lifecycle of aircraft propulsion systems. Whether during the product development phase or the in-service period, engine testing is continuously needed. Due to this fact the facilities have to cope with the changing eorts which appeared over the years. In order to investigate the inuences of dierent geometrical parameters on the performance of engine ground test facilities, a simplied model of the existing test facility of the Institute of Jet Propulsion at the University of the German Federal Armed Forces in Munich was designed and analyzed. This paper deals with the experimental results of the parametric studies performed with this model application. It also shows results of CFD studies and its validatiion, which were carried out in complement to the experimental approach.

Investigation of CFD Prediction Capabilities for Low Reynolds Turbine Aerodynamics

The objective of this work is to study the performance of low pressure turbines operating at low Reynolds numbers by extensive experiments and to validate numerical simulation results with the experimental data. Particular attention is payed to the prediction capabilities of current numerical turbulence and transition models in order to be able to benchmark the performance of future turbine airfoil profiles and to optimise their aero design. The LPT-Cascade under consideration has been investigated at the High Speed Cascade Wind Tunnel of the Institute of Jet Propulsion to gather information about the performance of turbine airfoils under low Reynolds operating conditions. The experiments were executed in the range of Re = 40′ 000 to 400′ 000 with steady state inflow conditions at different Mach number levels. The main focus of the investigation thereby was on the range of Re = 40′ 000 to 70′ 000. The high speed cascade wind tunnel of the University of Federal Armed Forces Munich allows for an independent Reynolds and Mach number variation such that an extensive database can be generated for realistic engine operation conditions. One major test objective was related to flow separation phenomena on the suction surface and its influence on the performance of the turbine profile. For this purpose both the loss behaviour and the pressure distribution on suction and pressure surface of the blade were measured and analysed. In addition to the experiments numerical flow simulations were conducted for the same turbine profile. In order to achieve more information on the influence of different turbulence and transition models on the flow separation, transition, and reattachment behaviour, two different CFD codes were used for comparison purposes. On the one hand the CFD code TRACE, which is developed by the German Aerospace Center (DLR) and MTU Aero Engines and on the other hand the general purpose code ANSYS CFX were applied. The aim is to assess the prediction capabilities of the different codes especially in the low Reynolds number range.© 2009 ASME