Three-Dimensional Flow Within a Turbine Cascade Passage

1977 ◽  
Vol 99 (1) ◽  
pp. 21-28 ◽  
Author(s):  
L. S. Langston ◽  
M. L. Nice ◽  
R. M. Hooper
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Three Dimensional ◽  
Field Tests ◽  
Turbine Cascade ◽  
Three Dimensional Flow ◽  
Aerodynamic Loss ◽  
Wall Flow ◽  
Layer Flow ◽  
End Wall

Detailed measurements of the subsonic flow in a large-scale, plane turbine cascade were made to evaluate the three-dimensional nature of the flow field. Tests were conducted at a passage aspect ratio of 1.0 with a collateral inlet boundary layer. Flow visualization was done on airfoil and endwall surfaces. Velocity and pressure measurements were taken before and behind the cascade and in six axial planes within a cascade passage, using a five-hole probe. Hot wire measurements were taken in the endwall boundary layer within the cascade passage. The characteristics of the endwall boundary layer are presented, showing that three-dimensional separation is an important feature of end-wall flow. A large part of the endwall boundary layer was found to be very thin when compared to the cascade inlet boundary layer. Data showing the growth of aerodynamic loss through the passage are discussed.

Potential Flow Field Generated by Downstream Moving Bars and Propagated on a Turbine Blade at Low Reynolds Number

2011 ◽  
Author(s):  
Ve´ronique Penin ◽  
Pascale Kulisa ◽  
Franc¸ois Bario
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Numerical Study ◽  
Three Dimensional ◽  
Potential Effect ◽  
Navier Stokes ◽  
Turbine Cascade ◽  
Wake Interaction ◽  
Rotor Stator Interaction ◽  
The Stability

During the last few decades, the size and weight of turbo-machinery have been continuously reduced. However, by decreasing the distance between rows, rotor-stator interaction is strengthened. Two interactions now have the same magnitude: wake interaction and potential effect. Studying this effect is essential to understand rotor-stator interactions. Indeed, this phenomenon influences the whole flow, including the boundary layer of the upstream and downstream blades, ergo the stability of the flow and the efficiency of the machine. A large scale turbine cascade followed by a specially designed rotating cylinder system is used. Synchronised velocity LDA measurements on the vane profile show the flow and boundary layer behavior due to the moving bars. To help the general understanding and to corroborate our experimental results, numerical investigations are carried out with an unsteady three dimensional Navier-Stokes code. Moreover, the numerical study informs about the potential disturbance to the whole flow of the cascade.

Instability in a viscous flow driven by streamwise vortices

2001 ◽  
Vol 432 ◽  
pp. 127-166 ◽  
Author(s):  
K. W. BRINCKMAN ◽  
J. D. A. WALKER
Keyword(s):  
Boundary Layer ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Wall Layer ◽  
External Flow ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Wall Flow ◽  
Turbulent Wall ◽  
Near Wall

Unsteady separation processes at large finite, Reynolds number, Re, are considered, as well as the possible relation to existing descriptions of boundary-layer separation in the limit Re → ∞. The model problem is a fundamental vortex-driven three-dimensional flow, believed to be relevant to bursting near the wall in a turbulent boundary layer. Bursting is known to be associated with streamwise vortex motion, but the vortex/wall interactions that drive the near-wall flow toward breakdown have not yet been fully identified. Here, a simulation of symmetric counter-rotating vortices is used to assess the influence of sustained pumping action on the development of a viscous wall layer. The calculated solutions describe a three-dimensional flow at finite Re that is independent of the streamwise coordinate and consists of a crossflow plane motion, with a developing streamwise flow. The unsteady problem is constructed to mimic a typical cycle in turbulent wall layers and numerical solutions are obtained over a range of Re. Recirculating eddies develop rapidly in the near-wall flow, but these eddies are eventually bisected by alleyways which open up from the external flow region to the wall. At sufficiently high Re, an oscillation was found to develop in the streamwise vorticity field near the alleyways with a concurrent evolution of a local spiky behaviour in the wall shear. Above a critical value of Re, the oscillation grows rapidly in amplitude and eventually penetrates the external flow field, suggesting the onset of an unstable wall-layer breakdown. Local zones of severely retarded streamwise velocity are computed which are reminiscent of the low-speed streaks commonly observed in turbulent boundary layers. A number of other features also bear a resemblance to observed coherent structure in the turbulent wall layer.

Turbulent Boundary Layer Flow on the End Wall of a Cylindrical Vortex Chamber

1975 ◽  
Vol 189 (1) ◽  
pp. 305-315 ◽  
Author(s):  
T. J. Kotas
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Boundary Layer Flow ◽  
Three Dimensional ◽  
Vortex Chamber ◽  
Cylindrical Vortex ◽  
Layer Flow ◽  
Momentum Integral ◽  
End Wall

A presentation of some measurements of velocities in the turbulent boundary layer on the end wall of a vortex chamber. These show that the boundary layer flow is three-dimensional with large inward radial velocities. Consequently, most of the fluid entering the vortex chamber passes into the central region through the boundary layers on the end walls rather than the main space of the vortex chamber. A momentum integral solution is used to obtain an estimate of the radial flow through the end-wall boundary layers. A comparison of the theoretical curves with the experimental results gives support to the main assumptions used in the solutions.

scholarly journals Investigation Concerning the Fluid Flow in the Mixed-Flow Diffuser

1971 ◽  
Author(s):  
Shinji Honami ◽  
Keizo Tsukagoshi ◽  
Toshimichi Sakai ◽  
Ichiro Watanabe
Keyword(s):  
Boundary Layer ◽  
Fluid Flow ◽  
Velocity Profile ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Pressure Gradients ◽  
Flow Mechanism ◽  
Mixed Flow ◽  
Three Dimensional Flow ◽  
Layer Flow

Velocity profile measurements were performed on the flow in a mixed-flow diffuser with walls having equal cone angles. The aim of the present study is to understand the flow behavior and the relation between the flow patterns and the diffuser losses. The boundary layer flow accompanied by separation on the inner wall and the velocity normal to the diffuser walls were measured in detail to examine the three-dimensional flow behavior in the mixed-flow diffuser. Comparing with the radial diffuser, the mixed-flow diffuser had a more complicated flow mechanism as it had the pressure gradients of transverse and normal directions.

Experimental Investigation of Three-Dimensional Secondary Flow on the Endwall of a Blade Channel in an Axial Turbine Cascade

2000 ◽  
Author(s):  
Arkadiy F. Slitenko ◽  
Yuriy M. Jukov
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Preliminary Analysis ◽  
Large Scale ◽  
Three Dimensional ◽  
Generalized Equations ◽  
Turbine Cascade ◽  
Blade Cascade ◽  
Integral Characteristics ◽  
Dimensional Boundary

The local and integral characteristics of three-dimensional boundary layer were investigated in a large scale turbine blade cascade. The flow visualization was carried out for preliminary analysis of the flow structure on the endwall of a blade channel. Then the distribution of velocity components and flow angles in three-dimensional boundary layers was measured in detail. On the basis of the investigation results the generalized equations for calculation of boundary layer characteristics were determined.

Effects of Catalytic and Dry Low NOx Combustor Turbulence on Endwall Heat Transfer Distributions

2005 ◽  
Vol 127 (4) ◽  
pp. 414-424 ◽  
Author(s):  
F. E. Ames ◽  
P. A. Barbot ◽  
C. Wang
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
Catalytic Combustor ◽  
Vortex Systems

Endwall heat transfer distributions taken in a large-scale low speed linear cascade facility are documented for mock catalytic and dry low NOx (DLN) combustion systems. Inlet turbulence levels range from about 1.0% for the mock catalytic combustor condition to 14% for the mock dry low NOx combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Catalytic combustor endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the mock dry low NOx cases. Turbulence scales have been documented for both cases. Inlet boundary layers are relatively thin for both the mock catalytic and DLN combustor cases. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the mock catalytic and DLN combustor inlet cases. Both midspan and 95% span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

scholarly journals Boundary Layer Characteristics on the Buckets of a Large-Scale Turbine Stage: Part 1 — Profiles of Mean and Turbulent Velocity Vectors

1970 ◽  
Author(s):  
W. H. Day
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Three Dimensional ◽  
Turbulent Velocity ◽  
Velocity Magnitude ◽  
Dimensional Boundary ◽  
Layer Flow ◽  
Flow Effects ◽  
Visualization Techniques ◽  
High Degree

Data have been obtained on details of the three-dimensional boundary layer flow on rotating turbine buckets using hot-wire anemometer and flow visualization techniques. Profiles of velocity magnitude and two angular directions are presented for both the mean and turbulent velocity vectors, as well as profiles of the three products of fluctuating velocities. The data were obtained along six flow paths covering the pressure and suction sides at three radial heights. A high degree of turbulence relative to the rotating buckets was found at all points in the boundary layer on both the pressure and suction sides. Also three-dimensional (radial flow) effects in the boundary layer were significant.

scholarly journals An Analysis of the Turbine Endwall Boundary Layer and Aerodynamic Losses

1975 ◽  
Author(s):  
T. C. Booth
Keyword(s):  
Boundary Layer ◽  
Layer Thickness ◽  
Shape Factor ◽  
Boundary Layer Thickness ◽  
Energy Equation ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Aerodynamic Loss ◽  
Flow Configurations ◽  
Momentum Integral

A momentum-integral analysis of the three-dimensional flow on the turbine endwall is presented. The formulation is for a compressible turbulent boundary layer with a constant streamwise shape factor. The effect of compressibility enters through a coordinate transformation and an assumed energy equation. An aerodynamic loss model is derived using inner and outer expansions. The losses decompose into frictional losses on the annulus and a vortex loss. Results are predicted for four cascade tests. In addition, previously observed trends of loss versus inlet boundary layer thickness, blade height, and blade chord are predicted. To illustrate a possible application, a parametric study is presented showing the effect on losses and heat transfer of various inlet boundary layer thickness distributions, which simulates different secondary flow configurations.

Effects of Catalytic and Dry Low NOx Combustor Turbulence on Endwall Heat Transfer Distributions

2003 ◽  
Author(s):  
F. E. Ames ◽  
P. A. Barbot ◽  
C. Wang
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Field ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Linear Cascade ◽  
Catalytic Combustor ◽  
Vortex Systems

Endwall heat transfer distributions taken in a large-scale low speed linear cascade facility are documented for mock catalytic and dry low NOx (DLN) combustion systems. Inlet turbulence levels range from about 1.0 percent for the mock catalytic combustor condition to 14 percent for the mock dry low NOx combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Catalytic combustor endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the mock dry low NOx cases. Turbulence scales have been documented for both cases. Inlet boundary layers are relatively thin for both the mock catalytic and DLN combustor cases. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the mock catalytic and DLN combustor inlet cases. Both midspan and 95 percent span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.

Particle Image Velocimetry Measurements of the Three-Dimensional Flow in an Exhaust Hood Model of a Low-Pressure Steam Turbine

2006 ◽  
Vol 129 (2) ◽  
pp. 411-419 ◽  
Author(s):  
Wei Zhang ◽  
Bu Geun Paik ◽  
Young Gil Jang ◽  
Sang Joon Lee ◽  
Su Eon Lee ◽  
...  
Keyword(s):  
Flow Structure ◽  
Large Scale ◽  
Particle Image ◽  
Guide Vane ◽  
Three Dimensional ◽  
Vortical Flow ◽  
Exhaust Hood ◽  
Three Dimensional Flow ◽  
Image Velocimetry ◽  
End Wall

The three-dimensional flow structure inside an exhaust hood model of a low-pressure steam turbine was investigated using a particle image velocimetry (PIV) velocity field measurement technique. The PIV measurements were carried out in several selected planes under design operation conditions with simulated total pressure distribution and axial velocity profile. The mean flow fields revealed a complicated vortical flow structure and the major sources of energy loss. Vortices with different scales were observed inside the exhaust hood: a strong separation vortex (SV) behind the tip of the guide vane, a longitudinal vortex (LV) at the exhaust hood top, a large-scale passage vortex (PV) evolving throughout the flow path, and an end-wall vortex (EWV) in the region adjacent to the front end-wall. Both the SV and the large-scale PV seemed to consume large amounts of kinetic energy and reduce the pressure recovery ability. The results indicate that the steam guide vane and the bearing cone should be carefully designed so as to control the vortical flow structure inside the exhaust hood.

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