Experimental Investigation of a High-Speed Turbine With Rainbow Rotor and Rim Seal Purge Flow

Cernat, Bogdan C.; Pinho, Jorge; Okada, Mizuki; Lavagnoli, Sergio

doi:10.1115/1.4056776

Cited by 4 publications

(2 citation statements)

References 35 publications

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“…Besides, the employment of pricey high-speed cameras should be avoided under such circumstances due to possible damage to the image sensor. The removal of the undesired reflection was achieved in the fluorescent particle images as shown in figure 13 The PLA method and the simulation setup are described in [7] and [8], respectively. Figure 15 shows yaw angle profiles extracted from figure 14 (c)-(e) along with the dotted lines 𝐿 1 and 𝐿 2 .…”

Section: Resultsmentioning

confidence: 99%

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A fluorescent PIV technique for turbomachinery flows

Okada

Pinho

Cernat

et al. 2023

J. Phys.: Conf. Ser.

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This paper presents the development and applications of a fluorescent Particle Image Velocimetry (PIV) technique as a countermeasure for undesired light reflections on surfaces of channel walls or obstacles. The employment of the fluorescent dye-doped tracer particle with a wavelength-specific optical filter enables a separation of the stokes-shifted particle light emission from reflections on the surfaces. Aiming at applying the technique to engine-like turbomachinery flows, the fluorescent tracer particles were made out of pyrromethene 567 and Di-Ethyl-Hexyl-Sebacat considering multiple aspects of characteristics. The developed particles were firstly tested in a low-speed wind tunnel with a metal turbine blade placed in the flow path and a laser sheet oriented to impinge the blade surface. With the installation of an adequate optical filter, the undesired light reflections were successfully removed, and reasonable vector calculations were enabled in proximity to the reflective blade surfaces. Secondly, the fluorescent PIV was performed on a high-pressure turbine stage hosted in a high-speed short-duration rotating turbine rig to demonstrate the feasibility of the technique in engine-representative turbomachinery flows.

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Section: Resultsmentioning

confidence: 99%

“…In total 250 and 229 datasets were applicable for Mie scattering and fluorescent PIV-PLA. The PLA method and the simulation setup are described in[7] and[8], respectively. Figure15shows yaw angle profiles extracted from figure14 (c)-(e) along with the dotted lines 𝐿 1 and 𝐿 2 .…”

mentioning

confidence: 99%

A fluorescent PIV technique for turbomachinery flows

Okada

Pinho

Cernat

et al. 2023

J. Phys.: Conf. Ser.

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Adaptation of von Karman Institute for Fluid Dynamics’ Isentropic Compression Tube Facility for High-Speed Low-Pressure Turbines Testing

Torre,

Merli,

Valle

et al. 2023

Journal of Turbomachinery

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This paper presents the commissioning of a newly designed High-Speed Low-Pressure Turbine (LPT) stage, operating at transonic exit Mach numbers and low Reynolds numbers, typical of modern geared turbofan (GTF) applications. At first, the characteristics of the research turbine are illustrated. The LPT stage is designed with an equal number of stationary vanes and shrouded rotor blades. The upstream and downstream hub cavities are purged and feature engine-realistic rim seals. The nominal operating condition of the stage is reported, along with a set of off-design conditions, obtained by varying rotor speed and purge mass flows. The second part of the paper describes the substantial revamping of the CT3 large-scale compression tube at Von Karman Institute for Fluid Dynamics, traditionally employed for high-pressure turbine testing, now adapted to host a high-speed LPT stage. The third section is an overview of the time-averaged and fast-response instrumentation. The dataset for each operating conditions includes aerothermal measurements in the annulus flow, in the hub cavities and in the shroud labyrinth seal. In addition, in this section is presented the design of an in-house traversing system for continuous probe traversing during the test. Finally, the outcome of the commissioning phase is discussed, with particular emphasis on the operating conditions stability, as well as on the inlet and cavity injection uniformity. The commissioning of a traversing system for continuous probe traversing during the short-duration test is also discussed.

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Unsteady Interaction Between Purge Flow and Secondary Flow in High-Lift Low-Pressure Turbine

Qu,

Wu,

Zhang

et al. 2024

Journal of Turbomachinery

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The coupling effect between the complex vortex system and the rim purge flow in the endwall region of a high-lift low pressure turbine (LPT) will significantly influence the evolution of secondary flow and the corresponding losses. This paper focused on the unsteady interaction mechanism between the rim purge flow and the secondary flow inside the high-lift LPT under the periodic wake passing. The large eddy simulation (LES) method was used to reveal the influence mechanism of rim purge flow, rotor-stator cavity interaction and unsteady wakes on the secondary flow. Detailed experimental measurement was carried out for the flow field of high-lift LPT under the influences of static purge flow. The results showed that the rim purge flow significantly increased the overturning and underturning downstream of the endwall region, resulting in aggravating secondary loss. The rotating-rim increased the difference of the circumferential velocity between the mainstream and the purge flow, aggravating the Kelvin-Helmholtz (K-H) instability, inducing the K-H vortex structure with stronger energy amplitude, and further increasing the endwall flow loss. The incoming wakes weakened the energy amplitude of the K-H vortex at the rim purge outlet, thinned the thickness of the low-energy fluid at the blade leading edge. Additionally, the interaction between the wakes and the secondary vortices further suppressed the development of the secondary flow. Nevertheless, the incoming wakes caused additional mixing losses and made a negative impact on the overall aerodynamic performance of the high-lift LPT.

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Experimental Investigation of a High-Speed Turbine With Rainbow Rotor and Rim Seal Purge Flow

Cited by 4 publications

References 35 publications

A fluorescent PIV technique for turbomachinery flows

A fluorescent PIV technique for turbomachinery flows

Adaptation of von Karman Institute for Fluid Dynamics’ Isentropic Compression Tube Facility for High-Speed Low-Pressure Turbines Testing

Unsteady Interaction Between Purge Flow and Secondary Flow in High-Lift Low-Pressure Turbine

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