Comparison of the Aerodynamics of Acoustically Designed Exit Guide Vanes and a State-of-the-Art Exit Guide Vane

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
Andreas Marn ◽  
Dominik Broszat ◽  
Thorsten Selic ◽  
Florian Schönleitner ◽  
Franz Heitmeir
Keyword(s):  
State Of The Art ◽  
Guide Vane ◽  
Power Level ◽  
Operating Point ◽  
Guide Vanes ◽  
Low Pressure Turbine ◽  
Sound Power Level ◽  
University Of Technology ◽  
Aero Engines ◽  
Engine Operating Point

Within previous EU projects, possible modifications to the engine architecture have been investigated, which would allow for an optimized aerodynamic or acoustic design of the exit guide vanes (EGVs) of the turbine exit casing (TEC). However, the engine weight should not be increased and the aerodynamic performance must be at least the same. This paper compares a state-of-the art TEC (reference TEC) with typical EGVs with an acoustically optimized TEC configuration for the engine operating point approach. It is shown that a reduction in sound power level for the fundamental tone (one blade passing frequency (BPF)) for this acoustically important operating point can be achieved. It is also shown that the weight of the acoustically optimized EGVs (only bladings considered) is almost equal to the reference TEC, but a reduction in engine length can be achieved. Measurements were conducted in the subsonic test turbine facility (STTF) at the Institute for Thermal Turbomachinery and Machine Dynamics, Graz University of Technology. The inlet guide vanes (IGVs), the low pressure turbine (LPT) stage, and the EGVs have been designed by MTU Aero Engines.

Comparison of the Aerodynamics of Acoustically Designed EGVs and a State-of-the-Art EGV

2014 ◽  
Author(s):  
Andreas Marn ◽  
Thorsten Selic ◽  
Florian Schönleitner ◽  
Franz Heitmeir ◽  
Dominik Broszat
Keyword(s):  
State Of The Art ◽  
Power Level ◽  
Operating Point ◽  
Guide Vanes ◽  
Acoustic Design ◽  
Low Pressure Turbine ◽  
Sound Power Level ◽  
University Of Technology ◽  
Aero Engines ◽  
Engine Operating Point

Within previous EU projects, possible modifications to the engine architecture have been investigated, that would allow for an optimised aerodynamic or acoustic design of the exit guide vanes (EGV) of the turbine exit casing (TEC). However, the engine weight should not be increased and the aerodynamic performance must be at least the same. This paper compares a state-of-the art TEC (reference TEC) with typical EGVs with an acoustically optimised TEC configuration for the engine operating point approach. It is shown that a reduction in sound power level for the fundamental tone (1 blade passing frequency) for this acoustically important operating point can be achieved. It is also shown that the weight of the acoustically optimised EGVs (only bladings considered) is almost equal to the Reference TEC, but a reduction in engine length can be achieved. Measurements were conducted in the subsonic test turbine facility (STTF) at the Institute for Thermal Turbomachinery and Machine Dynamics, Graz University of Technology. The inlet guide vanes, the low pressure turbine (LPT) stage, and the EGVs have been designed by MTU Aero Engines.

CFD Computation of Fan Interaction Noise

2007 ◽  
Author(s):  
Sheryl M. Grace ◽  
Douglas L. Sondak ◽  
Daniel J. Dorney ◽  
Michaela Logue
Keyword(s):  
Surface Pressure ◽  
Second Harmonic ◽  
Guide Vane ◽  
Power Level ◽  
Broadband Noise ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Fan Noise ◽  
Guide Vanes ◽  
Blade Passage

In this study, a 3-D, unsteady, Reynolds-averaged Navier-Stokes (RANS) CFD code coupled to an acoustic calculation is used to predict the contribution of the exit guide vanes to tonal fan noise downstream. The configuration investigated is that corresponding to the NASA Source Diagnostic Test (SDT) 22-in fan rig. One configuration from the SDT matrix is considered here: the approach condition, and outlet guide vane count designed for cut-off of the blade passage frequency. In this chosen configuration, there are 22 rotor blades and 54 stator blades. The stators are located 2.5 tip chords downstream of the rotor trailing edge. The RANS computations are used to obtain the spectra of the unsteady surface pressure on the exit guide vanes. The surface pressure at the blade passage frequency and its second harmonic are then integrated together with the Green’s function for an annular duct to obtain the pressure at locations in the duct. Comparison of the computed sound power level at the exhaust plane with experiment show good agreement at the cut-on circumferential mode. The results from this investigation validate the use of the CFD code along with the acoustic model for downstream fan noise predictions. This validation enables future investigations such as the effect of duct variation on the exhaust tonal power level and the validity of using this method for predicting broadband noise levels.

scholarly journals Detailed Experimental Study of the Flow in a Turbine Rear Structure at Engine Realistic Flow Conditions

2020 ◽  
Author(s):  
Valentin Vikhorev ◽  
Valery Chernoray ◽  
Oskar Thulin ◽  
Srikanth Deshpande ◽  
Jonas Larsson
Keyword(s):  
Suction Side ◽  
Flow Conditions ◽  
Local Flow ◽  
Low Pressure Turbine ◽  
University Of Technology ◽  
Flow Reynolds Number ◽  
Outlet Flow ◽  
Engine Mount ◽  
Inlet Conditions ◽  
Aero Engines

Abstract A good aerodynamic design of the turbine rear structure (TRS) is crucial for improving efficiency and reducing emissions from aero-engines. This paper presents a detailed experimental evaluation of an engine realistic TRS which was studied in an engine-realistic rig at Chalmers University of Technology, Sweden. The TRS test section was equipped with three types of outlet guide vanes (OGVs) which are typical of modern state-of-the-art TRS: regular vanes, thickened vanes and vanes with an engine mount recess (a shroud bump). Each of the three vane geometries were studied under on-design and off-design conditions at a fixed flow Reynolds number of 235,000. The study shows that the off-design performance of the TRS strongly depends on the presence of the local flow separation on the OGV suction side near the hub, which is greatly affected by the vane pressure distribution and inlet conditions. Similarly, the OGVs with increased thickness and with a vane shroud bump are shown to affect the performance of the TRS by influencing the losses on the OGV suction side near the hub. Furthermore, the presence of the bump is shown to have noticeable upstream influence on the outlet flow from the low-pressure turbine and noticeable downstream influence on the outlet flow from the TRS.

scholarly journals Detailed Experimental Study of the Flow in a Turbine Rear Structure at Engine-Realistic Flow Conditions

2021 ◽  
pp. 1-11
Author(s):  
Valentin Vikhorev ◽  
Valery Chernoray ◽  
Oskar Thulin ◽  
Srikanth Deshpande ◽  
Jonas Larsson
Keyword(s):  
Suction Side ◽  
Flow Conditions ◽  
Local Flow ◽  
Low Pressure Turbine ◽  
University Of Technology ◽  
Flow Reynolds Number ◽  
Outlet Flow ◽  
Engine Mount ◽  
Inlet Conditions ◽  
Aero Engines

Abstract A good aerodynamic design of the turbine rear structure (TRS) is crucial for improving efficiency and reducing emissions from aero-engines. This paper presents a detailed experimental evaluation of an engine realistic TRS which was studied in an engine-realistic rig at Chalmers University of Technology, Sweden. The TRS test section was equipped with three types of outlet guide vanes (OGVs) which are typical of modern state-of-the-art TRS: regular vanes, thickened vanes and vanes with an engine mount recess (a shroud bump). Each of the three vane geometries were studied under on-design and off-design conditions at a fixed flow Reynolds number of 235,000. The study shows that the off-design performance of the TRS strongly depends on the presence of the local flow separation on the OGV suction side near the hub, which is greatly affected by the vane pressure distribution and inlet conditions. Similarly, the OGVs with increased thickness and with a vane shroud bump are shown to affect the performance of the TRS by influencing the losses on the OGV suction side near the hub. Furthermore, the presence of the bump is shown to have noticeable upstream influence on the outlet flow from the low-pressure turbine and noticeable downstream influence on the outlet flow from the TRS.

Turbine Noise Reduction: Axial Spacing and Embedded Design

2015 ◽  
Author(s):  
C. Faustmann ◽  
S. Zerobin ◽  
S. Bauinger ◽  
A. Marn ◽  
F. Heitmeir ◽  
...  
Keyword(s):  
Power Level ◽  
Low Pressure ◽  
Sound Power ◽  
Noise Generation ◽  
Turbine Stage ◽  
Noise Emission ◽  
Low Pressure Turbine ◽  
Sound Power Level ◽  
Embedded Design ◽  
Lp Turbine

This paper deals with the investigation on the acoustics of different turning mid turbine frames (TMTF) in the two-stage two-spool test turbine located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The facility is a continuously operating cold-flow open-circuit plant which is driven by pressurized air. The flow path consists of a transonic turbine stage (HP) followed by a low pressure turbine stage made of a turning mid turbine frame (TMTF) and a counter-rotating low pressure rotor. Downstream of the low pressure turbine a measurement section is instrumented with acoustic sensors. Three TMTF setups have been investigated at engine like flow conditions. The first configuration (C1) consists of 16 highly 3D-shaped turning struts. The goal of the second design (C2) was to reduce the length of the TMTF by 10% without increasing the losses and providing comparable inflow to the LP turbine rotor. This was achieved by applying 3D-contoured endwalls at the hub. The third one (C3) is a new embedded concept for the turning mid turbine frame with two zero-lift splitters placed into the strut passages. In total 48 vanes (16 struts plus 32 splitter vanes) guide the flow from the HP rotor to the LP rotor. The comparison in terms of noise generation and propagation of the turbines is done by the microphones signal spectra, the emitted sound pressure and sound power level of each TMTF setup. Therefore the acoustic field is characterized by azimuthal and radial modes by means of a microphone array at the outer casing traversed over 360 degrees. By comparing the first two setups (C1 and C2) in terms of noise generation the propagating modes due to the HP turbine were found to be the same, while a difference of 5 dB in amplitude of the modes related to the LP turbine was found due to the different axial spacing between both setups. In the multi-splitter configuration (C3), the overall sound power level depending on the blade passing frequency (BPF) of the HP turbine is reduced by 7 dB and depending on the BPF of the LP turbine by 4 dB compared to C1, respectively. The overall effect is a reduction of the noise emission for the HP turbine due to the embedded design as well as for the LP turbine due to increasing the axial spacing between the TMTF Vanes and LP Blades on the one hand and considerably due to the embedded design on the other hand.

Experimental Investigation of the Upstream Effect of Different Low Pressure Turbine Exit Guide Vane Designs on Rotor Blade Vibration

2016 ◽  
Author(s):  
F. Schönleitner ◽  
T. Selic ◽  
C. Schitter ◽  
F. Heitmeir ◽  
A. Marn
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Low Pressure ◽  
Operating Conditions ◽  
Numerical Code ◽  
Noise Emission ◽  
Blade Vibration ◽  
Vibration Measurements ◽  
Guide Vanes ◽  
Low Pressure Turbine

Exit guide vanes of turbine exit casings are designed to meet aerodynamic, structural and acoustic criteria. New low pressure turbine architectures of aero engines try to optimize components weight in order to decrease the fuel consumption and reduce noise emissions. For this purpose different designs of turbine exit guide vanes (TEGV) exist which vary geometry as well as the number of vanes in the casing. In the subsonic test turbine facility at the Institute for Thermal Turbomachinery and Machine Dynamics of Graz University of Technology, which represents a 1 ½ low pressure turbine stage, the upstream effect of these innovative turbine exit casings (TEC) designs is under investigation. Up to now the influence of the turbine exit casing in relation to the aerodynamic vibration excitation of the rotor blading is not well known. For rotor blade vibration measurements a telemetry system in combination with strain gauges is applied. The present paper is a report of blade vibration measurements within a rotating system in the area of low pressure turbines under engine relevant operating conditions. Within the test phase different turbine exit casings are under investigation at two different operating points (OP). These turbine exit casings represent different design goals, e.g. aerodynamically optimization was performed to reduce losses at the aero design point or an acoustically optimization was done to reduce noise emission at the operating point approach. All these different design intents lead to a changed upstream effect, thus changing rotor blade vibrations. To identify parameters affecting blade vibration attention is paid to aerodynamic measurements as well. Selected results of steady and unsteady flow field measurements are analyzed to draw conclusions. The upstream effect of different turbine exit casings can be quantified at OP1. Depending on the vane number both the potential effect of the TEGV increase and the upstream effect as well. Aerodynamic as well as acoustic improvements as wanted with H-TEC and inverse-cut-off TEC lead to unfavorable conditions and higher blade loading in comparison to the referenced TEC. OP2 provides additional information of downstream effects. Due to the stator vane number the rotor blading is excited in its 4th eigenfrequency. The comparison between all investigated turbine exit casings with respect to the referenced configuration provides a basis for numerical code validation and future developments.

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