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Franz Heitmeir - One of the best experts on this subject based on the ideXlab platform.

  • On the acoustics of a turning mid turbine frame with Embedded Design in a two-stage test-turbine
    Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2015
    Co-Authors: Christian Faustmann, Stefan Zerobin, Andreas Marn, Franz Heitmeir, Rosario Spataro, Emil Göttlich
    Abstract:

    The paper deals with the investigation of the noise generation in the two-stage two-spool test turbine located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) at Graz University of Technology. The facility is a continuously operating cold-flow open-circuit plant which is driven by pressurized air. The flow path is formed by a transonic turbine stage (high pressure, HP) followed by a low pressure (LP) turbine stage consisting of a turning mid turbine frame and a counter-rotating LP rotor. Downstream of the low pressure turbine the measurement section is instrumented with acoustic sensors. The acquisition system consists of a fully circumferentially traversable microphone array located at the outer casing. Two configurations of turning mid turbine frames were tested. The baseline is an intermediate turbine duct with 16 turning struts. The second one is a new Embedded concept for the turning mid turbine frame with two zero-lift splitters placed in the struts’ passages. In total 48 vanes (16 struts plus 32 splitter vanes) guide the flow from the HP rotor to the LP rotor. In order to determine the noise emission of both configurations the microphones signal spectra and the emitted sound power level are compared. The acoustic field is characterized by azimuthal and radial modes by means of a microphone array traversed over 360°. In the multi-splitter configuration, the overall sound power level depending on the blade passing frequency of the HP turbine is reduced by 7 dB and depending on the blade passing frequency of the LP turbine by 4 dB, respectively. The overall effect is a reduction of the acoustic emission for the turning mid turbine frame with Embedded Design.

  • Turbine Noise Reduction: Axial Spacing and Embedded Design
    Volume 2B: Turbomachinery, 2015
    Co-Authors: Christian Faustmann, Stefan Zerobin, Sabine Bauinger, Andreas Marn, Franz Heitmeir, Emil Göttlich
    Abstract:

    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.Copyright © 2015 by ASME

  • Development of a Turning Mid Turbine Frame With Embedded Design—Part II: Unsteady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    © 2014 by ASME. The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

  • Development of a Turning Mid Turbine Frame With Embedded Design—Part I: Design and Steady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

  • Developement of a Turning Mid Turbine Frame With Embedded Design: Part I — Design and Steady Measurements
    Volume 6B: Turbomachinery, 2013
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter rotating low pressure stage like the spools of a modern high bypass aero engine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is consequently reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

Rosario Spataro - One of the best experts on this subject based on the ideXlab platform.

  • Flow Evolution Through a Turning Midturbine Frame with Embedded Design
    Journal of Propulsion and Power, 2017
    Co-Authors: Pascal Bader, Rosario Spataro, Wolfgang Sanz, Emil Göttlich
    Abstract:

    The paper discusses the time-averaged flow of a new-concept turbine transition duct placed in a two-stage counter-rotating test turbine. As a possible architecture for the turbine transition duct o...

  • On the acoustics of a turning mid turbine frame with Embedded Design in a two-stage test-turbine
    Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2015
    Co-Authors: Christian Faustmann, Stefan Zerobin, Andreas Marn, Franz Heitmeir, Rosario Spataro, Emil Göttlich
    Abstract:

    The paper deals with the investigation of the noise generation in the two-stage two-spool test turbine located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) at Graz University of Technology. The facility is a continuously operating cold-flow open-circuit plant which is driven by pressurized air. The flow path is formed by a transonic turbine stage (high pressure, HP) followed by a low pressure (LP) turbine stage consisting of a turning mid turbine frame and a counter-rotating LP rotor. Downstream of the low pressure turbine the measurement section is instrumented with acoustic sensors. The acquisition system consists of a fully circumferentially traversable microphone array located at the outer casing. Two configurations of turning mid turbine frames were tested. The baseline is an intermediate turbine duct with 16 turning struts. The second one is a new Embedded concept for the turning mid turbine frame with two zero-lift splitters placed in the struts’ passages. In total 48 vanes (16 struts plus 32 splitter vanes) guide the flow from the HP rotor to the LP rotor. In order to determine the noise emission of both configurations the microphones signal spectra and the emitted sound power level are compared. The acoustic field is characterized by azimuthal and radial modes by means of a microphone array traversed over 360°. In the multi-splitter configuration, the overall sound power level depending on the blade passing frequency of the HP turbine is reduced by 7 dB and depending on the blade passing frequency of the LP turbine by 4 dB, respectively. The overall effect is a reduction of the acoustic emission for the turning mid turbine frame with Embedded Design.

  • Unsteady CFD simulation of a turning mid turbine frame with Embedded Design
    2015
    Co-Authors: Pascal Bader, Wolfgang Sanz, Johannes Peterleithner, Rosario Spataro
    Abstract:

    This paper discusses the unsteady CFD simulation results of a new concept of an intermediate turbine duct between the high and low pressure turbine of a jet engine. In order to meet the requirements of future jet engines it is helpful to supply the S-shaped intermediate turbine duct with struts carrying the bearing loadings. These struts can be aerodynamically optimized to generate swirl in order to replace the first vane row of the subsequent low pressure rotor. In such a Design large flow structures coming from the outlet of the transonic high pressure stage are transported towards the low pressure rotor and are superimposed by secondary flows generated by the turning struts within the duct. These effects lead to a very inhomogeneous flow reaching the downstream low pressure rotor which leads to higher losses of this rotor. In order to reduce the fluctuations behind the S-shaped duct and to homogenize the flow, the duct can be equipped with splitters. Such an Embedded Design can homogenize the duct outlet flow, thus improving efficiency. In this paper the results of a steady and unsteady CFD simulation of such a turning mid turbine frame with splitters as experimentally investigated in the transonic test turbine facility at the Institute for Thermal Turbomachinery and Machine Dynamics of Graz University of Technology are discussed. A special focus is laid on the interaction between the high pressure stage and the intermediate turbine duct and the thus induced unsteady effects. Expected differences between the steady and unsteady simulation are shown. Additionally the positive effect of the splitters on the uniformity of the flow is investigated.

  • Flow Evolution Through a Turning Mid Turbine Frame With Embedded Design
    Volume 2C: Turbomachinery, 2014
    Co-Authors: Pascal Bader, Rosario Spataro, Wolfgang Sanz, Emil Göttlich
    Abstract:

    Copyright © 2014 by ASME. The paper discusses the time-averaged flow of a new concept turbine transition duct placed in a two-stage counter-rotating test turbine located at the Institute for Thermal Turbomachinery and Machine Dynamics of Graz University of Technology. As a possible architecture for the turbine transition duct of future engines, the structural vanes carrying the bearing loadings can be integrated with the first low pressure vane row in one aerodynamically optimized wide-chord vane. Such architecture is also called Turning Mid Turbine Frame (TMTF). In order to increase the flow uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, a baseline TMTF was reDesigned embedding two splitter vanes into the strut passage. The discussion on the flow field is based on numerical results obtained by a CFD code and validated by aerodynamic measurements. The flow structures moving from the outlet of the transonic high pressure stage are observed propagating towards the low pressure stage. In particular the splitter vanes are seen playing a major role in suppressing the big structures generated by the struts. On the other hand new losses are introduced by the splitter structures. Such structures play a decisive role in the overall component performance and therefore their effect should be properly understood in the Design phase. This work provides a deep insight into the flow physics of TMTF Designed with an Embedded concept for next generation aero-engines. This configuration is seen to be a promising architecture in order to compact the engine size while keeping the components performance high.

  • Development of a Turning Mid Turbine Frame With Embedded Design—Part II: Unsteady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    © 2014 by ASME. The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

Emil Göttlich - One of the best experts on this subject based on the ideXlab platform.

  • Flow Evolution Through a Turning Midturbine Frame with Embedded Design
    Journal of Propulsion and Power, 2017
    Co-Authors: Pascal Bader, Rosario Spataro, Wolfgang Sanz, Emil Göttlich
    Abstract:

    The paper discusses the time-averaged flow of a new-concept turbine transition duct placed in a two-stage counter-rotating test turbine. As a possible architecture for the turbine transition duct o...

  • On the acoustics of a turning mid turbine frame with Embedded Design in a two-stage test-turbine
    Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2015
    Co-Authors: Christian Faustmann, Stefan Zerobin, Andreas Marn, Franz Heitmeir, Rosario Spataro, Emil Göttlich
    Abstract:

    The paper deals with the investigation of the noise generation in the two-stage two-spool test turbine located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) at Graz University of Technology. The facility is a continuously operating cold-flow open-circuit plant which is driven by pressurized air. The flow path is formed by a transonic turbine stage (high pressure, HP) followed by a low pressure (LP) turbine stage consisting of a turning mid turbine frame and a counter-rotating LP rotor. Downstream of the low pressure turbine the measurement section is instrumented with acoustic sensors. The acquisition system consists of a fully circumferentially traversable microphone array located at the outer casing. Two configurations of turning mid turbine frames were tested. The baseline is an intermediate turbine duct with 16 turning struts. The second one is a new Embedded concept for the turning mid turbine frame with two zero-lift splitters placed in the struts’ passages. In total 48 vanes (16 struts plus 32 splitter vanes) guide the flow from the HP rotor to the LP rotor. In order to determine the noise emission of both configurations the microphones signal spectra and the emitted sound power level are compared. The acoustic field is characterized by azimuthal and radial modes by means of a microphone array traversed over 360°. In the multi-splitter configuration, the overall sound power level depending on the blade passing frequency of the HP turbine is reduced by 7 dB and depending on the blade passing frequency of the LP turbine by 4 dB, respectively. The overall effect is a reduction of the acoustic emission for the turning mid turbine frame with Embedded Design.

  • Turbine Noise Reduction: Axial Spacing and Embedded Design
    Volume 2B: Turbomachinery, 2015
    Co-Authors: Christian Faustmann, Stefan Zerobin, Sabine Bauinger, Andreas Marn, Franz Heitmeir, Emil Göttlich
    Abstract:

    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.Copyright © 2015 by ASME

  • Flow Evolution Through a Turning Mid Turbine Frame With Embedded Design
    Volume 2C: Turbomachinery, 2014
    Co-Authors: Pascal Bader, Rosario Spataro, Wolfgang Sanz, Emil Göttlich
    Abstract:

    Copyright © 2014 by ASME. The paper discusses the time-averaged flow of a new concept turbine transition duct placed in a two-stage counter-rotating test turbine located at the Institute for Thermal Turbomachinery and Machine Dynamics of Graz University of Technology. As a possible architecture for the turbine transition duct of future engines, the structural vanes carrying the bearing loadings can be integrated with the first low pressure vane row in one aerodynamically optimized wide-chord vane. Such architecture is also called Turning Mid Turbine Frame (TMTF). In order to increase the flow uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, a baseline TMTF was reDesigned embedding two splitter vanes into the strut passage. The discussion on the flow field is based on numerical results obtained by a CFD code and validated by aerodynamic measurements. The flow structures moving from the outlet of the transonic high pressure stage are observed propagating towards the low pressure stage. In particular the splitter vanes are seen playing a major role in suppressing the big structures generated by the struts. On the other hand new losses are introduced by the splitter structures. Such structures play a decisive role in the overall component performance and therefore their effect should be properly understood in the Design phase. This work provides a deep insight into the flow physics of TMTF Designed with an Embedded concept for next generation aero-engines. This configuration is seen to be a promising architecture in order to compact the engine size while keeping the components performance high.

  • Development of a Turning Mid Turbine Frame With Embedded Design—Part II: Unsteady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    © 2014 by ASME. The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

Christian Faustmann - One of the best experts on this subject based on the ideXlab platform.

  • On the acoustics of a turning mid turbine frame with Embedded Design in a two-stage test-turbine
    Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 2015
    Co-Authors: Christian Faustmann, Stefan Zerobin, Andreas Marn, Franz Heitmeir, Rosario Spataro, Emil Göttlich
    Abstract:

    The paper deals with the investigation of the noise generation in the two-stage two-spool test turbine located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) at Graz University of Technology. The facility is a continuously operating cold-flow open-circuit plant which is driven by pressurized air. The flow path is formed by a transonic turbine stage (high pressure, HP) followed by a low pressure (LP) turbine stage consisting of a turning mid turbine frame and a counter-rotating LP rotor. Downstream of the low pressure turbine the measurement section is instrumented with acoustic sensors. The acquisition system consists of a fully circumferentially traversable microphone array located at the outer casing. Two configurations of turning mid turbine frames were tested. The baseline is an intermediate turbine duct with 16 turning struts. The second one is a new Embedded concept for the turning mid turbine frame with two zero-lift splitters placed in the struts’ passages. In total 48 vanes (16 struts plus 32 splitter vanes) guide the flow from the HP rotor to the LP rotor. In order to determine the noise emission of both configurations the microphones signal spectra and the emitted sound power level are compared. The acoustic field is characterized by azimuthal and radial modes by means of a microphone array traversed over 360°. In the multi-splitter configuration, the overall sound power level depending on the blade passing frequency of the HP turbine is reduced by 7 dB and depending on the blade passing frequency of the LP turbine by 4 dB, respectively. The overall effect is a reduction of the acoustic emission for the turning mid turbine frame with Embedded Design.

  • Turbine Noise Reduction: Axial Spacing and Embedded Design
    Volume 2B: Turbomachinery, 2015
    Co-Authors: Christian Faustmann, Stefan Zerobin, Sabine Bauinger, Andreas Marn, Franz Heitmeir, Emil Göttlich
    Abstract:

    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.Copyright © 2015 by ASME

  • Development of a Turning Mid Turbine Frame With Embedded Design—Part II: Unsteady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    © 2014 by ASME. The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

  • Development of a Turning Mid Turbine Frame With Embedded Design—Part I: Design and Steady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

  • Developement of a Turning Mid Turbine Frame With Embedded Design: Part I — Design and Steady Measurements
    Volume 6B: Turbomachinery, 2013
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter rotating low pressure stage like the spools of a modern high bypass aero engine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is consequently reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

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  • Development of a Turning Mid Turbine Frame With Embedded Design—Part II: Unsteady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    © 2014 by ASME. The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

  • Development of a Turning Mid Turbine Frame With Embedded Design—Part I: Design and Steady Measurements
    Journal of Turbomachinery, 2014
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter-rotating low pressure (LP) stage like the spools of a modern high bypass aeroengine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part of the paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is, consequently, reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

  • Developement of a Turning Mid Turbine Frame With Embedded Design: Part I — Design and Steady Measurements
    Volume 6B: Turbomachinery, 2013
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    The paper presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to simulate the flow behavior of a transonic turbine followed by a counter rotating low pressure stage like the spools of a modern high bypass aero engine. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of turning struts placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on the setup over the last years, which were used as baseline for this paper, showed that wide chord vanes induce large wakes and extended secondary flows at the LP rotor inlet flow. Moreover, unsteady interactions between the two turbines were observed downstream of the LP rotor. In order to increase the uniformity and to decrease the unsteady content of the flow at the inlet of the LP rotor, the mid turbine frame was reDesigned with two zero-lifting splitters Embedded into the strut passage. In this first part paper the Design process of the splitters and its critical points are presented, while the time-averaged field is discussed by means of five-hole probe measurements and oil flow visualizations. The comparison between the baseline case and the Embedded Design configuration shows that the new Design is able to reduce the flow gradients downstream of the turning struts, providing a more suitable inlet condition for the low pressure rotor. The improvement in the flow field uniformity is also observed downstream of the turbine and it is consequently reflected in an enhancement of the LP turbine performance. In the second part of this paper the influence of the Embedded Design on the time-resolved field is investigated.

  • Development of a Turning Mid Turbine Frame With Embedded Design: Part II — Unsteady Measurements
    Volume 6B: Turbomachinery, 2013
    Co-Authors: Rosario Spataro, Christian Faustmann, Emil Göttlich, Davide Lengani, Franz Heitmeir
    Abstract:

    The paper, which is constituted by two parts, presents a new setup for the two-stage two-spool facility located at the Institute for Thermal Turbomachinery and Machine Dynamics (ITTM) of Graz University of Technology. The rig was Designed in order to reproduce the flow behavior of a transonic turbine followed by a counter rotating low pressure stage like those in high bypass aero-engines. The meridional flow path of the machine is characterized by a diffusing S-shaped duct between the two rotors. The role of wide chord vanes placed into the mid turbine frame is to lead the flow towards the LP rotor with appropriate swirl. Experimental and numerical investigations performed on this setup over the last years showed that the wide chord struts induce large wakes and extended secondary flows at LP inlet flow. Moreover, large deterministic fluctuations of pressure, which may cause noise and blade vibrations, were observed downstream of the LP rotor. In order to minimize secondary vortices and to damp the unsteady interactions, the mid turbine frame was reDesigned to locate two zero-lifting splitters into the vane passage. While in the first part paper the Design process of the splitters and the time-averaged flow field were presented, in this second part the measurements performed by means of a fast response probe will support the explanation of the time-resolved field. The discussion will focus on the comparison between the baseline case (without splitters) and the Embedded Design.