Impact of Individual High-Pressure Turbine Rotor Purge Flows on Turbine Center Frame Aerodynamics

Zerobin, Stefan; Aldrian, Christian; Peters, A.; Heitmeir, Franz; Göttlich, Emil

doi:10.1115/gt2017-63616

Cited by 8 publications

(3 citation statements)

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“…The measurement campaign is carried out in its entirety in the Transonic Test Turbine Facility (TTTF) of the Graz University of Technology (Institute of Thermal Turbomachinery and Machine Dynamics, ITTM). The TTTF is a dual-spool, continuous, open-circuit test bench historically devoted to the aerothermal investigation of intermediate turbine frames [19][20][21]. The main flow is supplied to the turbine by a 3 MW compression station, while a 560 kW suction blower, placed downstream of the test section, allows to decrease and stabilize the backpressure against ambient condition variations.…”

Section: Facility and Test Vehiclementioning

confidence: 99%

Aerodynamics and Sealing Performance of the Downstream Hub Rim Seal in a High-Pressure Turbine Stage

Merli

Krajnc

Hafizovic

et al. 2023

IJTPP

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The purpose of the paper is to characterize the aerodynamic behavior of a rotor-downstream hub cavity rim seal in a high-pressure turbine (HPT) stage. The experimental data are acquired in the Transonic Test Turbine Facility at the Graz University of Technology: the test setup includes two engine-representative turbine stages (the last HPT stage and first LPT stage), with the intermediate turbine duct in between. All stator-rotor cavities are supplied with purge flows by a secondary air system, which simulates the bleeding air from the compressor stages of the real engine. The HPT downstream hub cavity is provided with wall taps and pitot tubes at different radial and circumferential locations, which allows the performance of steady pressure and seed gas concentration measurements for different purge mass flows and HPT vanes clocking positions. Moreover, miniaturized pressure transducers are adopted to evaluate the unsteady pressure distribution, and an oil flow visualization is performed to retrieve additional information on the wheel space structures. The annulus pressure asymmetry depends on the HPT vane clocking, but this is shown to have negligible impact on the minimum purge mass flow required to seal the cavity. However, the hub pressure profile drives the distribution of the cavity egress in the turbine channel. The unsteady pressure field is dominated by blade-synchronous oscillations. No non-synchronous components with comparable intensity are detected.

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Section: Facility and Test Vehiclementioning

confidence: 99%

Aerodynamics and Sealing Performance of the Downstream Hub Rim Seal in a High-Pressure Turbine Stage

Merli

Krajnc

Hafizovic

et al. 2023

IJTPP

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show abstract

“…[3][4][5] In general, the rim seal flow is considered to decrease blade loading of the rotor and intensify the secondary flow loss which deteriorates the aerodynamic performance. [6][7][8] Therefore, it is essential to investigate the impact of the rim seal flow on the mainstream for elucidating the flow and loss mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the blockage effect caused by rim seal flow

Fan

Wang

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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Blockage effect caused by the rim seal flow is one of the most important sources of loss in the interaction between the turbine rim seal flow and mainstream and has not been investigated in detail. To research the blockage effect, numerical simulations were presented for different rim seal flow rates. The pressure distribution was investigated and losses resulting from the blockage effect were analyzed. In addition, the influences of swirl ratio, inclination angle, and width were revealed. Results show that the blockage effect originates from the pushing and compression of egress flow to the mainstream and results in local pressure increase. The egress flow mainly blocks the mainstream downstream of the stator suction side and above the egress flow. Furthermore, the blockage effect strengthens with the increase of rim seal flow rate and weakens with the increase of swirl ratio. The effect of inclination angle and width on the blockage effect could be neglected. With the increase of rim seal flow rate, the blockage on the stator suction side causes the secondary losses to be reduced and the increasing expansion in the rotor passage leads to more losses at the tip and surface. A loss isolation method that defines the space region of loss in the rotor domain is established and proven to be effective. On an average, relative to the design condition, the overall loss introduced by the blockage effect increases by about 89.44% per 1% increase in the rim seal flow rate.

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“…Schrewe et al [18] performed an efficiency measurement and found an efficiency drop with the increase of rim seal mass flow rate in a two-stage low-pressure turbine. Zerobin et al [19,20] investigated the influence of four individual purge flows on the aerodynamic performance of turbine center frames with a 1.5-stage turbine test setup. Purge flow injection intensified secondary flow structures in main annulus flow and increased pressure fluctuations on the platform.…”

Section: Introductionmentioning

confidence: 99%

Particle Image Velocimetry (PIV) Investigation of Blade and Purge Flow Impacts on Inter-Stage Flow Field in a Research Turbine

Zhang

2019

Energies

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Flow field in the inter-stage is of great importance to jet engine turbine performance and efficiency. Investigation of flow fields is limited by the complex geometrical structure. Traditional measurement techniques, such as hot wire, pressure probe and laser Doppler velocimetry (LDV) can hardly obtain a planar information of the flow field simultaneously. To overcome this difficulty, an instantaneous planar velocimetry technique, the particle image velocimetry (PIV) technique is widely employed. However, there is no publication that studied the detailed flow field by PIV in a turbine inter-stage with the consideration of the influence of rotor blade and purge flow. This paper presents a quasi-three dimensional perspective of flow field between inlet guide vane (IGV) and rotor blade in a research turbine inter-stage by using a 2D PIV system. Coherent structures in the flow field are extracted by the proper orthogonal decomposition (POD) method. Time-averaged results show the ellipsoid structures caused by secondary flow in the inter-stage. Rotor blade influence to axial and radial flow is evaluated by time-averaged data and the first order POD mode. Egress of purge flow (9.4% of main annulus flow rate) leads to a domain with 60% axial velocity loss near hub and a growth over three times in radial velocity. POD analysis of purge flow shows detailed flow migration in the whole measurement plane.

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Impact of Individual High-Pressure Turbine Rotor Purge Flows on Turbine Center Frame Aerodynamics

Cited by 8 publications

References 0 publications

Aerodynamics and Sealing Performance of the Downstream Hub Rim Seal in a High-Pressure Turbine Stage

Aerodynamics and Sealing Performance of the Downstream Hub Rim Seal in a High-Pressure Turbine Stage

Numerical investigation of the blockage effect caused by rim seal flow

Particle Image Velocimetry (PIV) Investigation of Blade and Purge Flow Impacts on Inter-Stage Flow Field in a Research Turbine

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