Investigation on the Flow in a Rotor-Stator Cavity with Centripetal Through-Flow

Hu, Bo; Brillert, Dieter; Dohmen, Hans Josef; Benra, Friedrich-Karl

doi:10.3390/ijtpp2040018

Cited by 18 publications

(26 citation statements)

References 15 publications

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“…The SST-model is known to handle separation in adverse pressure gradients, while having the advantages of a turbulent viscosity model regarding computational effort and stability. In other publications, the model has shown good agreement with measurements in rotor-stator cavities (Hu et al, 2017;Barabas et al, 2015) -the primary focus of this study.…”

Section: Computational Setupsupporting

confidence: 64%

“…The different leakage flows through the cavities affect axial thrust and disk torque (Hu et al, 2017 andSun et al, 2009). Due to the differences in temperature and leakage, the combined frictional losses of the cavities in the CHT model are 2-5% higher than in the adiabatic model.…”

Section: Secondary Effectsmentioning

confidence: 99%

“…Literature shows that the inclusion of rotor-stator cavities is crucial to the correct reproduction of stage characteristics: (Hu et al, 2017) and (Sun et al, 2009), amongst others, research centripetal flow through rotor-stator cavities and show how axial thrust and disk torque are affected. (Guidotti et al, 2012) show the influence of cavity modelling on the efficiency and pressure ratio.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Conjugate Heat Transfer Study of a Centrifugal Compressor with Impeller Cavities

Stahl¹,

Franz²,

Ittern³

2019

GPPS Zurich19

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In this study the effects of heat transfer on the rotorstator cavity temperatures and the characteristics of one industrial, single stage centrifugal compressor are examined. A baseline Computational Fluid Dynamics (CFD) analysis of the fluid with adiabatic (AD) boundary conditions is conducted. The relevant solid bodies are added to the model and a Conjugate Heat Transfer (CHT) calculation of the machine is performed. The two models are compared and validated by experimental data. Most research regarding heat transfer in centrifugal compressors focusses on turbocharger or gas turbine applications, where a significant heat flux from the adjacent turbine is expected. Industrial compressors are often treated as adiabatic. Some publications include the solid body of the impeller in the calculation, but cavities are often not in the focus of the study. Efforts to obtain reliable Heat Transfer Coefficients (HTC) by employing simple correlations for the impeller flow in the presence of a shroud cavity leakage have not yet proven to be successful. When comparing the CHT and the adiabatic model, differences can be observed in wall-and cavity flow temperatures. The adiabatic approach exceeds the measured cavity temperatures by 40%, whereas the CHT calculation yields significantly better results and stays within a margin of error of 1-4%. Additionally, the qualitative temperature distribution and calculated frictional power loss of both models differ noticeably. The bulk flow seems nearly unchanged and the adiabatic approach proves to be sufficient to describe overall compressor performance. Differences in efficiency, total pressure ratio and total temperature ratio between the two models are negligible. For machines engineered to maximum mechanical loads, with tight restrictions in fluid temperature, or if thermal expansion of the components is critical (e.g. tight sealing clearances), a CHT simulation is recommended for more accurate temperature predictions.

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Section: Computational Setupsupporting

confidence: 64%

Section: Secondary Effectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Conjugate Heat Transfer Study of a Centrifugal Compressor with Impeller Cavities

Stahl¹,

Franz²,

Ittern³

2019

GPPS Zurich19

View full text Add to dashboard Cite

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“…Kurokawa et al [23][24][25] investigated C F and C M in an enclosed rotor-stator cavity with centrifugal or centripetal through-flow. From the axial thrust measurements, Hu et al [26] determined a correlation for C F in a rotor-stator cavity with centripetal through-flow. Based on the simulation results of velocity profiles, a part of the 2D Daily and Nece diagram was extended into 3D with a third axis of through-flow coefficient C D .…”

Section: Introductionmentioning

confidence: 99%

Investigation on Thrust and Moment Coefficients of a Centrifugal Turbomachine

Brillert

Dohmen

et al. 2018

IJTPP

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In radial pumps and turbines, the centrifugal through-flow in both the front and the back chambers is quite common. It strongly impacts the core swirl ratio, pressure distribution, axial thrust and frictional torque. In order to investigate these relationships experimentally, a test rig was designed at the University of Duisburg-Essen and described in this paper. Based on both the experimental and numerical results, correlations are determined to predict the impacts of the centrifugal through-flow on the core swirl ratio, the thrust coefficient and the moment coefficient. Two correlations respectively are determined to associate the core swirl ratio with the local through-flow coefficient for both Batchelor type flow and Stewartson type flow. The correlations describing the thrust coefficient and the moment coefficient in a rotor-stator cavity with centripetal through-flow (Hu et al., 2017) are modified for the case of centrifugal through-flow. The Daily and Nece diagram distinguishing between different flow regimes in rotor-stator cavities is extended with a through-flow coordinate into 3D. The achieved results provide a comprehensive data base which is intended to support the calculation of axial thrust and moment coefficients during the design process of radial pumps and turbines in a more accurate manner.

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“…It covers a Reynolds number range of 3.8 × 10 5 ≤ Re ≤ 3.2 × 10 6 and an axial gap width range of 0.0182 ≤ G ≤ 0.0728. A more detailed description can be found in [8][9][10]. The large test rig, first introduced by Barabas et al [11], can reach Reynolds numbers up to Re = 2.5 × 10 8 since it has a large disc radius and is operated with carbon dioxide.…”

Section: Introductionmentioning

confidence: 99%

Impact of Leakage Inlet Swirl Angle in a Rotor–Stator Cavity on Flow Pattern, Radial Pressure Distribution and Frictional Torque in a Wide Circumferential Reynolds Number Range

Schröder

Dohmen

Brillert

et al. 2020

IJTPP

Self Cite

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In the side-chambers of radial turbomachinery, which are rotor–stator cavities, complex flow patterns develop that contribute substantially to axial thrust on the shaft and frictional torque on the rotor. Moreover, leakage flow through the side-chambers may occur in both centripetal and centrifugal directions which significantly influences rotor–stator cavity flow and has to be carefully taken into account in the design process: precise correlations quantifying the effects of rotor–stator cavity flow are needed to design reliable, highly efficient turbomachines. This paper presents an experimental investigation of centripetal leakage flow with and without pre-swirl in rotor–stator cavities through combining the experimental results of two test rigs: a hydraulic test rig covering the Reynolds number range of 4 × 10 5 ≤ R e ≤ 3 × 10 6 and a test rig for gaseous rotor–stator cavity flow operating at 2 × 10 7 ≤ R e ≤ 2 × 10 8 . This covers the operating ranges of hydraulic and thermal turbomachinery. In rotor–stator cavities, the Reynolds number R e is defined as R e = Ω b 2 ν with angular rotor velocity Ω , rotor outer radius b and kinematic viscosity ν . The influence of circumferential Reynolds number, axial gap width and centripetal through-flow on the radial pressure distribution, axial thrust and frictional torque is presented, with the through-flow being characterised by its mass flow rate and swirl angle at the inlet. The results present a comprehensive insight into the flow in rotor–stator cavities with superposed centripetal through-flow and provide an extended database to aid the turbomachinery design process.

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Investigation on the Flow in a Rotor-Stator Cavity with Centripetal Through-Flow

Cited by 18 publications

References 15 publications

Conjugate Heat Transfer Study of a Centrifugal Compressor with Impeller Cavities

Conjugate Heat Transfer Study of a Centrifugal Compressor with Impeller Cavities

Investigation on Thrust and Moment Coefficients of a Centrifugal Turbomachine

Impact of Leakage Inlet Swirl Angle in a Rotor–Stator Cavity on Flow Pattern, Radial Pressure Distribution and Frictional Torque in a Wide Circumferential Reynolds Number Range

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