A Method for Calculating Axial Turbomachine End Wall Turbulent Boundary Layers

1989 ◽  
Author(s):  
Kang Shun ◽  
Liu Fengjun ◽  
Wang Zhongqi
Keyword(s):  
Boundary Layer ◽  
Iterative Solution ◽  
Stream Surface ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Curvilinear Coordinate ◽  
Orthogonal Curvilinear Coordinate System ◽  
Layer Flow ◽  
End Wall ◽  
Differential And Integral Equations

Based on two families of relative stream-surface theory, the differential and integral equations of the endwall boundary layer in the S2 stream surface (hub to tip stream surface) have been established in the orthogonal curvilinear coordinate system in the present paper. By directly associating the blade force defects with the warping of S2 stream surface near the endwall, we have proposed a new method for predicting the endwall boundary layer. This method can be used to conduct the interactions of the end wall boundary layer with the S2 stream surface potentisl flow, in order to get the iterative solution of the end wall boundary layer flow with the potential flow in S2 stream surface. The predicted results have shown that the present method is acceptable.

An experimental study of the three dimensional boundary layer on the end wall of a vortex chamber

1976 ◽  
Vol 352 (1669) ◽  
pp. 169-187 ◽  
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Vortex Chamber ◽  
Operating Conditions ◽  
Wall Friction ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Dimensional Boundary ◽  
Layer Flow ◽  
End Wall

Profiles of the radial and circumferential components of velocity have been measured in the end-wall boundary layer of a vortex chamber as part of an experimental and theoretical investigation of a confined, incompressible vortex flow. The profiles have been presented here for various radial positions and operating conditions and the main features of the boundary-layer have been discussed. Further, the circumferential profiles have been analysed by plotting them in two types of dimensionless coordinates. Also, the wall friction data corresponding to the circumferential direction have been plotted. Hence an empirical expression for the wall friction factor was obtained. The data presented here reveal some new features and provide new information on the end-wall boundary layer flow in a vortex chamber.

An Axial Compressor End-Wall Boundary Layer Calculation Method

1979 ◽  
Vol 101 (2) ◽  
pp. 233-245 ◽  
Author(s):  
J. De Ruyck ◽  
C. Hirsch ◽  
P. Kool
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Velocity Profile ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Wall Region ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
End Wall

An axial compressor end-wall boundary layer theory which requires the introduction of three-dimensional velocity profile models is described. The method is based on pitch-averaged boundary layer equations and contains blade force-defect terms for which a new expression in function of transverse momentum thickness is introduced. In presence of tip clearance a component of the defect force proportional to the clearance over blade height ratio is also introduced. In this way two constants enter the model. It is also shown that all three-dimensional velocity profile models present inherent limitations with regard to the range of boundary layer momentum thicknesses they are able to represent. Therefore a new heuristic velocity profile model is introduced, giving higher flexibility. The end-wall boundary layer calculation allows a correction of the efficiency due to end-wall losses as well as calculation of blockage. The two constants entering the model are calibrated and compared with experimental data allowing a good prediction of overall efficiency including clearance effects and aspect ratio. Besides, the method allows a prediction of radial distribution of velocities and flow angles including the end-wall region and examples are shown compared to experimental data.

scholarly journals LES and RANS Analysis of the End-Wall Flow in a Linear LPT Cascade: Part I — Flow and Secondary Vorticity Fields Under Varying Inlet Condition

2018 ◽  
Author(s):  
R. Pichler ◽  
Yaomin Zhao ◽  
R. D. Sandberg ◽  
V. Michelassi ◽  
R. Pacciani ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Secondary Flow ◽  
Flow Characteristics ◽  
Flow Region ◽  
Secondary Flows ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Wall Flow ◽  
End Wall ◽  
The Impact

In low-pressure-turbines (LPT) around 60–70% of losses are generated away from end-walls, while the remaining 30–40% is controlled by the interaction of the blade profile with the end-wall boundary layer. Experimental and numerical studies have shown how the strength and penetration of the secondary flow depends on the characteristics of the incoming end-wall boundary layer. Experimental techniques did shed light on the mechanism that controls the growth of the secondary vortices, and scale-resolving CFD allowed to dive deep into the details of the vorticity generation. Along these lines, this paper discusses the end-wall flow characteristics of the T106 LPT profile at Re = 120K and M = 0.59 by benchmarking with experiments and investigating the impact of the incoming boundary layer state. The simulations are carried out with proven Reynolds-averaged Navier–Stokes (RANS) and large-eddy simulation (LES) solvers to determine if Reynolds Averaged models can capture the relevant flow details with enough accuracy to drive the design of this flow region. Part I of the paper focuses on the critical grid needs to ensure accurate LES, and on the analysis of the overall time averaged flow field and comparison between RANS, LES and measurements when available. In particular, the growth of secondary flow features, the trace and strength of the secondary vortex system, its impact on the blade load variation along the span and end-wall flow visualizations are analysed. The ability of LES and RANS to accurately predict the secondary flows is discussed together with the implications this has on design.

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