Visualization and Time-Resolved Particle Image Velocimetry Measurements of the Flow in the Tip Region of a Subsonic Compressor Rotor

Tan, David; Li, Yuanchao; Wilkes, Ian; Miorini, Rinaldo L.; Katz, Joseph

doi:10.1115/1.4028433

Cited by 35 publications

(22 citation statements)

References 32 publications

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“…Yoon et al (2006) demonstrated that tip vortex becomes strengthened and migrates upstream as the flow coefficient decreases, which was also validated by Tan et al (2014) found that the evolution of TLV becomes more abrupt, in terms of the initial location and breakdown process near the pre-stall condition. Furthermore, using high-speed imaging, Tan et al (2012) also discovered that the sheet cavitation is thin at BEP condition, while it becomes thickened as a result of an increase in the incidence angle of the flow entering the passage relative to the blade.…”

Section: Effect Of Flow Coefficientmentioning

confidence: 61%

Visualized observations of trajectory and dynamics of unsteady tip cloud cavitating vortices in axial flow pump

Shi

Zhang

Zhao

et al. 2017

JFST

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A large-scale perpendicular cavitating vortices (PCVs), at the trailing edge of attached cavitation on the blade suction side near the tip region, has been found recently due to the great impact on performance breakdown in an axial waterjet pump. However, the trajectory and dynamics of this structure have been given scant attention. In this study, some visualized experiments were carried out to elucidate the PCVs for different conditions. The high-speed imaging coupled with numerical computations show that the vortical cloud cavitation is induced by the combination of tip leakage vortex (TLV) and radial re-entrant jets from the hub to blade tip. Moreover, the trajectory and intensity of PCVs depend on the operating conditions strongly, whether the other parameters, e.g. blade number and blade geometries, are modified. When taken the blade number into consideration, as a consequence of flow passage width and blade loading distributions, the dynamics and strength of PCVs vary considerably. Furthermore, an optimum clearance geometry is seen to eliminate corner vortex and clearance cavitation when the clearance edge is rounded on the pressure side. However, the more intensive tip leakage vortex cavitation is observed due to the increased amount of leakage flux. Additionally, in the original blade with sharp edges, the PCVs is relative weak and has a loose structure, resulting in the multiple interaction with the next blade. These phenomenon are responsible for the severe performance degradation and flow instabilities in the tip region of an axial-flow pump. Lei Shi, Zhang, Zhao, Weidong Shi and van Esch, Journal of Fluid Science and Technology, Vol.12, No.1 (2017) 7 low pressure in the vortex core (Arndt, 2002;Higashi et al., 2002;Murayama, 2006). Thus, cavitation inception is often coupled with vortex structures, such as tip leakage, trailing and hub vortices as well as turbulent vortex structures developing in regions of flow separation.In the aforementioned research, much attention has been paid to the tip leakage vortex cavitation around the fully-wetted hydrofoils (Boulon et al., 1999;Park et al., 2006;Dreyer et al., 2014). Although many progress has been made in regard to the vortex structures and self-induced cavitation, some important parameters are still missing in actual hydraulic machines, for instance, the body force in rotating frame which can alter the cavitation phenomenon. As a result, for the practical applications, the numerical and experimental investigations have been carried out in many rotating machines, both for single and multiphase flows. Farrell and Billet (1994) measured the important variables for the correlation which predict the vortex minimum pressure in a high Reynolds number axial-flow test rig. Moreover, an optimum tip clearance has been theoretically identified as experiments have shown. Afterwards, a combined study of tip clearance and tip vortex cavitation in an axial flow pump was carried out by Laborde et al. (1997). A conclusion is drawn that cavitation inception is...

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Section: Effect Of Flow Coefficientmentioning

confidence: 61%

Visualized observations of trajectory and dynamics of unsteady tip cloud cavitating vortices in axial flow pump

Shi

Zhang

Zhao

et al. 2017

JFST

View full text Add to dashboard Cite

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“…These are traditionally linked with the trajectory of the tip leakage vortex. From other investigations (e.g., [23,24]) it is known that this is a simplification and that, under certain operating conditions, the near casing flow field shows multiple vortical structures and not one clearly defined tip leakage vortex. This becomes obvious in our results at the largest tested tip clearance that is presented later.…”

Section: Time-resolved Casing Staticmentioning

confidence: 99%

Investigation of Performance and Rotor Tip Flow Field in a Low Speed Research Compressor with Circumferential Groove Casing Treatment at Varying Tip Clearance

Rolfes

Lange

Mailach

2017

International Journal of Rotating Machinery

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Experimental investigations in a single-stage low speed axial research compressor are presented. The influence of four different rotor tip clearances on the overall compressor performance and on the rotor tip flow field is investigated in configurations with and without circumferential groove casing treatments. Piezo-resistive pressure transducers are used to capture the unsteady flow field in the rotor tip region. The investigated casing groove is effectively working at the three largest investigated tip clearance sizes. The largest achieved operating range increase by the groove is 6.9%. The groove can delay the upstream movement of the flow interface between leakage flow and main flow and thus increase the stable operating range. Rotating instabilities are shown to exist at large tip clearance sizes in throttled operating conditions. Their amplitudes can be damped by the casing groove. No modal activities could be detected in the current single-stage compressor build.

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“…Those areas correspond to regions of high intensity for both the normal Reynolds stresses and the shear Reynolds stresses, as presented in figure 4 and figure 5. In the second area, around x 2 = 60mm and x 3 = −7mm , the production is believed to be an effect of the interaction between the tip-leakage vortex and the end-wall boundary-layer (Tan et al, 2015). The important production area in the jet is impacted by the high residual, but not entirely, while the other area of important production is not significantly impacted by the high residual.…”

Section: Turbulent Kinetic Energy Budgetmentioning

confidence: 98%

Budget Analysis of Turbulent Kinetic Energy in a Tip-Leakage Flow of a Single Blade: RANS Vs Zonal LES

Monier

Boudet

Caro

et al. 2017

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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This study aims at analyzing the modeling of turbulence in a tip-leakage flow. The academic configuration considered is made of a single airfoil and a flat casing, with clearance, at Re=9.3e5. For characterising the turbulence, a zonal large-eddy simulation (ZLES), validated against experimental data, is considered as reference. ZLES was previously shown to describe precisely the flow features in the tip region, including the Reynolds stresses. Two steady Reynolds-averaged Navier-Stokes (RANS) simulations, using Wilcox's k-ω model, are evaluated against this reference. The first simulation uses the Boussinesq constitutive relation, whereas the second simulation relies on the quadratic constitutive relation (QCR). The analysis focuses on the mean velocities, the Reynolds stresses and a term-to-term decomposition of the turbulent kinetic energy budget. RANS is shown to underestimate the vorticity of the flow, the Reynolds stresses and the turbulent kinetic energy budget terms. The QCR has little effects on these deficits. KEYWORDS TIP-LEAKAGE FLOW, SINGLE AIRFOIL, RANS, LES, REYNOLDS STRESSES, TURBULENT KINETIC ENERGY BUDGET NOMENCLATURE M Mach number ∆x + , ∆y + , ∆z + Cell sizes at the wall, in wall O Normalized rotation tensor units Re c Reynolds number based on Π Sub-grid scale stress tensor the chord length of the blade Ξ Numerical residual tensor U Free-stream velocity δ ij Kroeneker symbol c Chord-length of the blade ρ Density h Tip-clearance height τ Viscous stress tensor k Turbulent kinetic energy τ t \τ QCR t Reynolds stress tensor with p Pressure Boussinesq constitutive u 1 , u 2 , u 3 Stream-wise (resp. transverse relation \with QCR and span-wise) velocities ω Turbulent kinetic energy x 1 , x 2 , x 3 Stream-wise (resp. transverse specific dissipation rate and span-wise) directions

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Visualization and Time-Resolved Particle Image Velocimetry Measurements of the Flow in the Tip Region of a Subsonic Compressor Rotor

Cited by 35 publications

References 32 publications

Visualized observations of trajectory and dynamics of unsteady tip cloud cavitating vortices in axial flow pump

Visualized observations of trajectory and dynamics of unsteady tip cloud cavitating vortices in axial flow pump

Investigation of Performance and Rotor Tip Flow Field in a Low Speed Research Compressor with Circumferential Groove Casing Treatment at Varying Tip Clearance

Budget Analysis of Turbulent Kinetic Energy in a Tip-Leakage Flow of a Single Blade: RANS Vs Zonal LES

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