Journal ArticleDOI
Numerical Simulation of Tip Leakage Flows in Axial Flow Turbines, With Emphasis on Flow Physics: Part I — Effect of Tip Clearance Height
J. Tallman,B. Lakshminarayana +1 more
TLDR
In this article, a 3D Navier-Stokes CFD code was used to simulate the effects of turbine parameters on the tip leakage flow and vortex in a linear turbine cascade to understand the detailed flow physics.Abstract:
A pressure-correction based, 3D Navier-Stokes CFD code was used to simulate the effects of turbine parameters on the tip leakage flow and vortex in a linear turbine cascade to understand the detailed flow physics. A baseline case simulation of a cascade was first conducted in order to validate the numerical procedure with experimental measurements. The effects of realistic tip clearance spacing, inlet conditions, and relative endwall motion were then sequentially simulated, while maintaining previously modified parameters. With each additional simulation, a detailed comparison of the leakage flow's direction, pressure gradient, and mass flow, as well as the leakage vortex and its roll-up, size, losses, location, and interaction with other flow features, was conducted. Part I of this two-part paper focuses on the effect of reduced tip clearance height on the leakage flow and vortex. Reduced tip clearance results in less mass flow through the gap, a smaller leakage vortex, and less aerothermal losses in both the gap and the vortex. The shearing of the leakage jet and passage flow to which leakage vortex roll-up is usually attributed to is not observed in any of the simulations. Alternative explanations of the leakage vortex's roll-up are presented. Additional secondary flows that are seen near the casing are also discussed.read more
Citations
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Journal ArticleDOI
Performance-based health monitoring, diagnostics and prognostics for condition-based maintenance of gas turbines: A review
TL;DR: In this paper, a systematic review of recently developed engine performance monitoring, diagnostic and prognostic techniques is presented, which provides experts, students or novice researchers and decision-makers working in the area of gas turbine engines with the state of the art for performance-based condition monitoring.
Journal ArticleDOI
Flow Physics and Profiling of Recessed Blade Tips: Impact on Performance and Heat Load
TL;DR: In this article, an improved design of a recessed blade tip for a highly loaded axial turbine rotor blade with application in high pressure axial turbines in aero engine or power generation is presented.
Journal ArticleDOI
Transonic Turbine Blade Tip Aerothermal Performance With Different Tip Gaps—Part I: Tip Heat Transfer
TL;DR: A closely combined experimental and computational fluid dynamics (CFD) study on a transonic blade tip aerothermal performance at engine representative Mach and Reynolds numbers (Mexit=1,Reexit=1.27×106) is presented in this paper.
Journal ArticleDOI
Sediment erosion in hydro turbines and its effect on the flow around guide vanes of Francis turbine
TL;DR: In this article, the effects of sediment erosion of turbine components on the flow phenomenon are investigated. But the exact phenomenon of erosion of surface by the solid particles has not been fully understood, despite of centuries of investigations and research, despite the increasing number of hydropower plants are being built in the regions where rivers are heavily loaded with sediment.
Journal ArticleDOI
Effects of squealer rim height on aerodynamic losses downstream of a high-turning turbine rotor blade
Sang Woo Lee,Byoung Joo Chae +1 more
TL;DR: In this article, the effects of squealer rim height on three-dimensional flows and aerodynamic losses downstream of a high-turning turbine rotor blade have been investigated for a typical tip gap-to-chord ratio of h/c = 2.0%.
References
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Journal ArticleDOI
Predictions of Channel and Boundary-Layer Flows with a Low-Reynolds-Number Turbulence Model
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Journal ArticleDOI
The Development of Axial Turbine Leakage Loss for Two Profiled Tip Geometries Using Linear Cascade Data
J. P. Bindon,G. Morphis +1 more
TL;DR: In this paper, the authors used linear cascade experimental data as though it were a rotor with work transfer and found that radiused geometry, contoured to shed radial flow into the gap and reduce the leakage mass flow, was found to have a significantly higher efficiency.
Journal ArticleDOI
Numerical Simulation of Tip Clearance Effects in Turbomachinery
Anton Basson,B. Lakshminarayana +1 more
TL;DR: In this paper, an efficient grid generation scheme was developed for the analysis of turbulent turbomachinery flows and tip clearance flows, and a semi-implicit, pressure-based computational fluid dynamics scheme that directly includes artificial dissipation, and is applicable to both viscous and inviscid flows.
Proceedings ArticleDOI
Reduction of Tip Clearance Losses Through 3-D Airfoil Designs
TL;DR: In this article, the impact of spanwise stacking of turbine airfoil sections on tip clearance flows was investigated in a water tunnel by using linear cascades to validate the design concepts and the verification of the overall design concepts was executed in an uncooled full scale rotating rig.
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