Influence of Radial Inflow on Rotor-Stator Cavity Pressure Distributions

Hart, Kenneth J.; Turner, A. B.

doi:10.1115/94-gt-106

Cited by 3 publications

(5 citation statements)

References 8 publications

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“…This choice was based on various considerations, such as similarity in geometric configuration and flow conditions. The experimental data for the validation test come from Hart and Turner [12]. Figure 4 shows a schematic diagram of the fully shrouded rotor-stator system consisting of a rotor of 400 mm diameter (b=400 mm), spinning at up to 4400 r/min and separated from a shrouded stator by an axial air gap which can be varied from 2-23 mm in width.…”

Section: Validation Of the Computational Modelmentioning

confidence: 99%

Numerical investigation of radial inflow in the impeller rear cavity with and without baffle

Liu

et al. 2016

Sci. China Technol. Sci.

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In typical small engines, the cooling air for high pressure turbine (HPT) in a gas turbine engine is commonly bled off from the main flow at the tip of the centrifugal impeller. The pressurized air flow is drawn radially inwards through the impeller rear cavity. The centripetal air flow creates a strong vortex because of high inlet tangential velocity, which results in significant pressure losses. This not only restricts the mass flow rate, but also reduces the cooling air pressure for down-stream hot components. The present study is devoted to the numerical modeling of flow in an impeller rear cavity. The simulations are carried out with axisymmetric and 3-D sector models for various inlet swirl ratio  0 (0-0.6), turbulent flow parameter  T (0.028-0.280) with and without baffle. The baffle is a thin plate attached to the stationary wall of the cavity, and is proved to be useful in reducing the pressure loss of centripetal flow in the impeller rear cavity in the current paper. Further flow details in impeller rear cavity with and without baffle are displayed using CFD techniques. The CFD results show that for any specified geometry, the outlet pressure coefficient of impeller rear cavity with or without baffle depends only on the inlet swirl ratio and turbulent flow parameter. Meanwhile, the outlet pressure coefficient of the cavity with baffle is indeed smaller than that of cavity without baffle, especially for the cases with high inlet swirl ratio. The suppression of the effect of centrifugal pumping and the mixing beween the main air which is downstream of the baffle and the recirculating flow of the vortex in the stationary cavity, which are caused by the use of baffle, are the underlying reasons that lead to the reduction of outlet pressure loss.impeller rear cavity, de-swirling device, baffle, Batchelor's Model, Vortex Model Citation:Liu G, Du Q, Liu J, et al. Numerical investigation of radial inflow in the impeller rear cavity with and without baffle.

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Section: Validation Of the Computational Modelmentioning

confidence: 99%

Numerical investigation of radial inflow in the impeller rear cavity with and without baffle

Liu

et al. 2016

Sci. China Technol. Sci.

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“…A substantial amount of work has been performed by numerous researchers on the flow of fluid close to rotating discs. Hart and Turner (1994) contains a basic chronological review of some of this work and its relevance to rotor-stator cavity velocity and pressure variations.…”

Section: Theory and Review Of Previous Workmentioning

confidence: 99%

“…In order to promote confidence in the use of this CFD code for the assessment of impeller rear face rotor-stator cavity geometries and through flows, CFD models were produced to validate the code at most of the geometry and flow conditions tested on the experimental rig. This validation process was reported in Hart and Turner (1994).…”

Section: Computational Fluid Dynamics (Cfd)mentioning

confidence: 99%

“…Such an exercise would also allow anomalous points and trends to be more clearly identified and dealt with. The validation exercise reported in Hart and Turner (1994) compared values of 0 from rig test and CFD at an Re m of 1.0 x 106 with various throughflows. In many cases there was little difference between rig and CFD values but where there is discrepancy, and until it can be fully resolved, the user of these design curves is advised to perform a sensitivity check using As stated previously, the aim of these design curves is to provide guidance on the effect of geometry and bleed flows on rotor-stator cavity core tangential velocities to enable preliminary design and analysis work to be performed without recourse to expensive rig test and/or CFD work.…”

Section: Design Curvesmentioning

confidence: 99%

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Simple Design Methods for the Prediction of Radial Static Pressure Distributions in a Rotor-Stator Cavity With Radial Inflow

Hart

Turner

1995

Volume 1: Turbomachinery

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Research has been conducted into the effects of component geometry and air bleed flow on the radial variation of static pressure and core tangential velocity in a rotor-stator cavity of the type often found behind the impeller of a gas turbine engine centrifugal compressor. A CFD code, validated by rig test data for a wide range of rotor-stator axial gaps and throughflows, has been used to generate pressure and velocity data for typical gas turbine operating conditions. This data has been arranged as a series of simple design curves which relate the rotational speed of the core of fluid between rotor and stator boundary layers, and hence the static pressure distribution, to primary cavity geometry, rotational Reynolds number and bleed throughflow with particular attention to radial inflowing bleeds. Details are provided on the use and limitations of these curves. Predictions using this method have been compared successfully with measured data from engine test and a compressor test rig, modified to facilitate variable quantity and direction of impeller rear face bleed flow, at typical gas turbine operational power conditions. Data generated by these curves can be used directly in the design process and to validate integral momentum methods which can provide relatively simple computation of rotor-stator cavity pressure and velocity distributions independently or within air system network programs. This approach is considered to be a cost and time effective addition to the analytical design process especially if validated CFD code, which can accommodate rotational flows consistently and accurately, is not available.

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“…It is found that the value of β 0 has a significant influence on the distribution of the swirl ratio β in the central core region. Hart and Turner [9,10] used numerical and experimental methods to obtain the pressure and swirl ratio in the impeller rear cavities with different geometries and air bleed flow. The aim of their researches was to obtain a series of curves that can help predict velocity and pressure distribution quickly and accurately without the need for costly CFD work or rig testing during the initial engine design phase.…”

Section: Introductionmentioning

confidence: 99%

Computational Investigation of Flow Control Methods in the Impeller Rear Cavity

Liu

et al. 2020

International Journal of Aerospace Engineering

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In typical median and small aeroengines, the air used to realize the functions such as cooling of turbine blades and disks, sealing of turbine cavities and bearing chambers, adjusting of rotating assembly axial load is normally drawn through the rear cavity of centrifugal impeller, so the thorough understanding of flow characteristics and pressure distribution and the proposal of the corresponding control methods in the cavity are the key to design the rational secondary air system. With an impeller rear cavity in a small turbofan engine as an object, the current study was dedicated to the investigation of flow control methods in the cavity. Two methods, namely, baffle and swirl-controlled orifice, were proposed to regulate the pressure loss and distribution in the cavity. Furthermore, the influence of geometry parameters of the two methods such as the length of baffle, the space between the baffle and rotating disk wall, the orientation, and radial position of swirl-controlled orifice was investigated. The CFD results show that the swirl-controlled orifice which could deswirl the flow is more effective in regulating the pressure loss and its distribution in cavity than baffle. The variation of the radial position of the swirl-controlled orifice had little influence on pressure loss but obvious influence on pressure distribution; therefore, decreasing the radial position could reduce the axial load on the rotating disk without changing the outlet pressure.

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Influence of Radial Inflow on Rotor-Stator Cavity Pressure Distributions

Cited by 3 publications

References 8 publications

Numerical investigation of radial inflow in the impeller rear cavity with and without baffle

Numerical investigation of radial inflow in the impeller rear cavity with and without baffle

Simple Design Methods for the Prediction of Radial Static Pressure Distributions in a Rotor-Stator Cavity With Radial Inflow

Computational Investigation of Flow Control Methods in the Impeller Rear Cavity

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