Tip leakage vortex and its breakdown mechanism in aspirated compressor cascades designed with conventional method and curvature induced pressure recovery concept

Cao, Zeyuan; Zhang, Xiang; Zhang, Fei; Song, Cheng; Gao, Xi; Liu, Bo

doi:10.1016/j.ast.2021.106692

Cited by 10 publications

(2 citation statements)

References 32 publications

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“…There are complex flow phenomena near the rotor tip clearance and stator blades of a transonic compressor, such as leakage flow, passage shock waves, boundary layer separation, and rotor-stator interaction, which enhance unsteady perturbations and reduce the compressor's stability. Vortex breakdown is highly likely to be the main cause of low-momentum flow generation near the blade tip [4][5][6], while the wake is the main cause of downstream stator perturbation. Therefore, it is essential to analyze the flow field characteristics in the region of rotor/stator interaction.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Unsteady Rotor–Stator Interaction Mechanism and Wake Transportation Characteristics in a Compressor with Non-Uniform Tip Clearance Rotor

Zhang,

Li,

Wang

et al. 2023

Energies

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This study aims to numerically investigate a transonic compressor by solving the unsteady Reynolds-averaged Navier–Stokes equations. The flow mechanisms related to unsteady flow were carefully examined and compared between rotors with non-uniform tip clearance (D1) and small-value tip clearance (P1). The unsteady flow field near the 50% and 95% blade span characterized by unsteady rotor–stator interaction was analyzed in detail for near-stall (NS) conditions. According to the findings, the perturbation of unsteady aerodynamic force for the stator is much bigger than that of the rotor. At the mid-gap between the rotor and stator, the perturbation of tangential velocity of the D1 scheme in the rotor and stator frame is reduced. At the rotor’s outlet region, the perturbation intensity is divided into three main perturbation regions, which are respectively concentrated in the TLV near the upper endwall, the corner separation at the blade root, and the wake of the whole blade span. Through the analysis of the wake transportation characteristics, it was found that when the wake passes through the stator blade surface, the wake exerts a substantial influence on the flow within the stator passage. It further leads to notable pressure perturbations on the stator’s surface, as well as affecting the development and flow loss of the boundary layer. The negative jet effect induces opposite secondary flow velocity on both sides of the wake near the stator’s surfaces. Therefore, the velocity at a specific point on the stator’s suction surface will decrease and then increase. Conversely, the velocity at a particular point on the pressure surface will increase and then decrease.

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Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Unsteady Rotor–Stator Interaction Mechanism and Wake Transportation Characteristics in a Compressor with Non-Uniform Tip Clearance Rotor

Zhang,

Li,

Wang

et al. 2023

Energies

Self Cite

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“…At the same time, many scholars have studied the influence of factors such as tip clearance and rotation speed on the internal flow pattern of fluid machinery. Shi et al [28][29][30] investigated the effect of tip clearance on the velocity distribution in a multiphase pump, the internal flow and velocity distribution characteristics in pump under different tip clearances were studied using experimental and numerical methods.Cao et al 31 investigated the effect of blade pressure distribution on tip leakage flows based on three aspirated blades, including the one designed with conventional method and the other two designed with curvature induced pressure recovery. Han and Tan 32 studied the influence of speed on the energy performance of mixedflow pumps, tip leakage flow, TLV structure, and pressure pulsation.…”

Section: Introductionsmentioning

confidence: 99%

Analysis on the escape phenomenon of oil mist from turbine lower guide bearing based on VOF model

Pang

Liu

et al. 2021

Advances in Mechanical Engineering

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To analyze the cause and mechanism of oil mist escaping from the lower guide bearing during the operation of a turbine, the oil-gas mixture in the lower guide bearing was numerically simulated by using the VOF two-phase flow model and the SST turbulence model. The influences of different sealing clearances and speeds on the flow field and the oil-gas distribution in the oil tank were studied, and the escaping characteristics of oil mist were analyzed. The results show that increasing the clearance of the labyrinth seal will reduce the pressure difference between the inside and outside of the oil tank and reduce the driving force for the escape of the oil mist. However, increasing the clearance will increase the turbulence of the flow field, the number and volume of bubbles in the lubricating oil, which will lead to the uneven distribution of oil and gas and reduce the motion stability of the lower guide bearing. The change of speed will affect the normal use of the shaft-collar pump. High speed will aggravate the generation of bubbles in the oil tank and increase the possibility of cavitation in the lower guide bearing structure. In engineering practices, it is necessary to comprehensively consider factors such as oil mist escape phenomenon, economic benefits, process manufacturing and assembly, and adopt the lower guide bearing structure with a suitable labyrinth seal clearance.

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Influence of Cavity Leakage flow on Corner Separation in a Shrouded Stator Cascade

Kong

Huang²,

Liu³

et al. 2022

J. Therm. Sci.

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Tip leakage vortex and its breakdown mechanism in aspirated compressor cascades designed with conventional method and curvature induced pressure recovery concept

Cited by 10 publications

References 32 publications

Numerical Investigation of Unsteady Rotor–Stator Interaction Mechanism and Wake Transportation Characteristics in a Compressor with Non-Uniform Tip Clearance Rotor

Numerical Investigation of Unsteady Rotor–Stator Interaction Mechanism and Wake Transportation Characteristics in a Compressor with Non-Uniform Tip Clearance Rotor

Analysis on the escape phenomenon of oil mist from turbine lower guide bearing based on VOF model

Influence of Cavity Leakage flow on Corner Separation in a Shrouded Stator Cascade

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