Numerical investigation on the effect of radial location of sealing air inlet and its geometry on the sealing performance of a stator-well cavity

Zhang, Feng; Wang, Xinjun; Li, Jun; Zheng, Dan

doi:10.1016/j.ijheatmasstransfer.2017.08.053

Cited by 10 publications

(4 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The rotating core is pushed radially inward by the vortex, forming an interface between the two. This flow structure is similar to that shown computationally by [10].…”

Section: Models Of Flow Structure In Rotor-stator Systemssupporting

confidence: 85%

See 1 more Smart Citation

Influence of Leakage Flows on Hot Gas Ingress

Patinios

Ong

Scobie

et al. 2018

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

One of the most important problems facing gas turbine designers today is the ingestion of hot mainstream gases into the wheel-space between the turbine disk (rotor) and its adjacent casing (stator). A rim seal is fitted at the periphery and a superposed sealant flow—typically fed through the bore of the stator—is used to prevent ingress. The majority of research studies investigating ingress do so in the absence of any leakage paths that exist throughout the engine's architecture. These inevitable pathways are found between the mating interfaces of adjacent pieces of hardware. In an environment where the turbine is subjected to aggressive thermal and centrifugal loading, these interface gaps can be difficult to predict and the resulting leakage flows which pass through them even harder to account for. This paper describes experimental results from a research facility which experimentally models hot gas ingestion into the wheel-space of an axial turbine stage. The facility was specifically designed to incorporate leakage flows through the stator disk; leakage flows were introduced axially through the stator shroud or directly underneath the vane carrier ring. Measurements of CO2 gas concentration, static pressure, and total pressure were used to examine the wheel-space flow structure with and without ingress from the mainstream gas-path. Data are presented for a simple axial-clearance rim-seal. The results support two distinct flow-structures, which are shown to be dependent on the mass-flow ratio of bore and leakage flows. Once the leakage flow was increased above a certain threshold, the flow structure is shown to transition from a classical Batchelor-type rotor-stator system to a vortex-dominated structure. The existence of a toroidal vortex immediately inboard of the outer rim-seal is shown to encourage ingestion.

show abstract

“…The rotating core is pushed radially inward by the vortex, forming an interface between the two. This flow structure is similar to that shown computationally by [10].…”

Section: Models Of Flow Structure In Rotor-stator Systemssupporting

confidence: 85%

“…Zhang et al [10] computationally investigated the introduction of sealing flow at various radial locations on the stationary surface of a stator-well cavity. The flow structure in the upstream stator-rotor wheel-space was shown to be affected by the radial extent of the inlet.…”

Section: Literature Reviewmentioning

confidence: 99%

Influence of Leakage Flows on Hot Gas Ingress

Patinios

Ong

Scobie

et al. 2018

Journal of Engineering for Gas Turbines and Power

View full text Add to dashboard Cite

show abstract

“…There is a two-fold impact: a reduction in bypass losses (therefore increasing useful work) and an increase in cavity swirl, thereby reducing shear stress and windage. Experiments and computations have shown that the location, geometry, and angle of the superposed flows strongly influence the sealing characteristics [6][7][8].…”

Section: Introduction and Review Of Relevant Researchmentioning

confidence: 99%

Windage Torque Reduction in Low-Pressure Turbine Cavities Part II: Experimental and Numerical Results

Jackson,

Li,

Christodoulou

et al. 2024

Journal of Turbomachinery

View full text Add to dashboard Cite

Minimizing the losses within a low-pressure turbine (LPT) system is critical for the design of next-generation ultra-high bypass ratio aero-engines. The stator-well cavity windage torque can be a significant source of loss within the system, influenced by the ingestion of mainstream annulus air with a tangential velocity opposite to that of the rotor. This paper presents experimental and numerical results of three carefully designed Flow Control Concepts (FCCs) – additional geometric features on the stator surfaces, which were optimized to minimize the windage torque within a scaled, engine-representative stator-well cavity. FCC1 and FCC2 featured rows of guide vanes at the inlet to the downstream and upstream wheel-spaces, respectively. FCC3 combined FCC1 and FCC2. Superposed flows were introduced to the upstream section of the cavity, which modelled the low radius coolant and higher radius leakage between the rotor blades. In addition to torque measurements, total and static pressures were collected, from which the cavity swirl ratio was derived. Additional swirl measurements were collected using a five-hole aerodynamic probe, which traversed radially at the entrance and exit of the cavity. A cavity windage torque reduction of 55% on the baseline (which has no flow control) was measured for FCC3, at the design condition with superposed flow. For this concept, an increase in the cavity swirl in both the upstream and downstream wheel-spaces was demonstrated experimentally and numerically. With increasing superposed flow, the contribution of FCC1 surpassed FCC2, due to more mass flow entering

show abstract

“…The rotating bolts generate unsteadiness due to wake shedding. Zhang et al [36] investigated the effects of the radial location of sealing air inlet hole and the shape of sealing air supply geometry on the flow characteristics and sealing performance of the stator-well cavity.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of hot gas ingestion into the rotor-stator disk cavities of a subscale 1.5-stage axial gas turbine

Ghasemian

Princevac

Kim³

et al. 2019

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

Both steady and unsteady Reynolds Averaged Navier-Stokes (RANS) techniques coupled with the k À e and k À x ðSSTÞ turbulence models are utilized to study the flow characteristics and hot gas ingestion through rim seal in a subscale 1.5-stage axial gas turbine. A scalar transport equation is solved for a tracer gas to represent the coolant flow interaction with the main stream flow. To validate the numerical methodology, radial pressure and sealing effectiveness distributions are compared with the experimental data. The k À x ðSSTÞ turbulence model has the capability to predict secondary flow characteristics, reattachment and separation, thus leading to better agreement with the experimental data. Both radial and circumferential pressure distributions are analyzed to get deeper insight into rotationally and externally induced ingress mechanisms. The circumferential pressure peak-to-trough amplitude is significantly attenuated in the cavity region compared to annulus region. Finally, different purge flow rates and rotational speeds are examined. Results indicate that as purge flow rate increases, the static pressure in the disk cavity region raises remarkably and consequently the sealing effectiveness improves. Averaged sealing effectiveness in the rim cavity decreases linearly with the rotational speed. To visualize different mechanisms of ingestion, streamline and flow field are shown.

show abstract

Numerical investigation on the effect of radial location of sealing air inlet and its geometry on the sealing performance of a stator-well cavity

Cited by 10 publications

References 31 publications

Influence of Leakage Flows on Hot Gas Ingress

Influence of Leakage Flows on Hot Gas Ingress

Windage Torque Reduction in Low-Pressure Turbine Cavities Part II: Experimental and Numerical Results

Numerical modeling of hot gas ingestion into the rotor-stator disk cavities of a subscale 1.5-stage axial gas turbine

Contact Info

Product

Resources

About