A Surface Vorticity Analysis of Three-Dimensional Flow through Strongly Swept Turbine Cascades

1974 ◽  
Vol 16 (6) ◽  
pp. 425-433 ◽  
Author(s):  
D. Graham ◽  
R. I. Lewis
Keyword(s):  
Three Dimensional ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Spanwise Direction ◽  
Three Dimensional Flow ◽  
End Effects ◽  
Dimensional Flow ◽  
Blade Row ◽  
Flow Through ◽  
The Subject

The two-dimensional surface vorticity theory of Martensen is extended to deal with the full three-dimensional flow through a swept turbine cascade, including end effects. Basic concepts of surface vorticity theories are dealt with initially, as also are three three-dimensional flow considerations for swept cascades. The paper goes on to develop two theoretical models for the representation of swept blade row flows. The first model assumes that the blade bound vorticity remains constant across the span of the blade. In the second model, this assumption is relaxed so that the blade bound vorticity is allowed to vary in the spanwise direction. In both cases the theories are applied to turbine nozzle cascades. Some of the solutions obtained are compared with experimental tests which were the subject of a previous paper.

Experimental Study of the Three-Dimensional Flow Field in an Annular Turbine Nozzle Guidevane

1984 ◽  
Vol 106 (2) ◽  
pp. 437-444 ◽  
Author(s):  
C. H. Sieverding ◽  
W. Van Hove ◽  
E. Boletis
Keyword(s):  
Guide Vane ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Pressure Distributions ◽  
Blade Row ◽  
Contour Plots ◽  
Crossflow Velocity ◽  
Flow Through ◽  
Double Head

The paper describes the experimental investigation of the three-dimensional flow through a low-speed, low aspect ratio, high turning annular turbine nozzel guide vane. The flow is explored by means of double-head, four-hole pressure probes in twelve axial planes from upstream to far downstream of the blade row. The results are presented under the form of contour plots and spanwise pitch-averaged distributions of losses, flow angles, and static pressure distributions. The concept of presenting the evolution of the endwall boundary layer under the form of streamwise and crossflow velocity components is discussed in detail.

Full Potential Solution of Transonic Quasi-Three-Dimensional Flow Through a Cascade Using Artificial Compressibility

1982 ◽  
Vol 104 (1) ◽  
pp. 143-153 ◽  
Author(s):  
C. Farrell ◽  
J. Adamczyk
Keyword(s):  
Reliable Method ◽  
Three Dimensional ◽  
Full Potential ◽  
Three Dimensional Flow ◽  
Artificial Compressibility ◽  
Dimensional Flow ◽  
Blade Row ◽  
Flow Through ◽  
Transonic Region ◽  
Good Agreement

A reliable method is presented for calculating the flowfield about a cascade of arbitrary two-dimensional airfoils. The method approximates the three-dimensional flow in a turbomachinery blade row by correcting for streamtube convergence and radius change in the throughflow direction. The method is a fully conservative solution of the full potential equation incorporating the finite volume technique on a body-fitted periodic mesh, with an artificial density imposed in the transonic region to ensure stability and the capture of shock waves. Comparison of results for several supercritical blades shows good agreement with their hodograph solutions. Other calculations for these profiles as well as standard NACA blade sections indicate that this is a useful scheme for analyzing both the design and off-design performance of turbomachinery blading.

Excess Streamwise Vorticity and Its Role in Secondary Flow

1987 ◽  
Vol 201 (6) ◽  
pp. 413-420 ◽  
Author(s):  
P W James
Keyword(s):  
Secondary Flow ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Point Of View ◽  
Streamwise Vorticity ◽  
Three Dimensional Flow ◽  
Approximate Methods ◽  
Blade Row ◽  
Flow Through ◽  
Loss Term

The purpose of this paper is, firstly, to show how the concept of excess secondary vorticity arises naturally from attempts to recover three-dimensional flow details lost in passage-averaging the equations governing the flow through gas turbines. An equation for the growth of excess streamwise vorticity is then derived. This equation, which allows for streamwise entropy gradients through a prescribed loss term, could be integrated numerically through a blade-row to provide the excess vorticity at the exit to a blade-row. The second part of the paper concentrates on the approximate methods of Smith (1) and Came and Marsh (2) for estimating this quantity and demonstrates their relationship to each other and to the concept of excess streamwise vorticity. Finally the relevance of the results to the design of blading for gas turbines, from the point of view of secondary flow, is discussed.

Three-Dimensional-Flow Theories for Axial Compressors and Turbines

1948 ◽  
Vol 159 (1) ◽  
pp. 255-268 ◽  
Author(s):  
A. D. S. Carter
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Physical Nature ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Three Dimensional Flow ◽  
Axial Compressors ◽  
Dimensional Flow ◽  
Blade Row

It has long been known that the energy losses occurring in an axial compressor or turbine cannot be fully accounted for by the skin-friction losses on the blades and annulus walls. The difference, usually termed secondary loss, is attributed to miscellaneous secondary flows which take place in the blade row. These flows both cause losses in themselves and modify the operating conditions of the individual blade sections, to the detriment of the overall performance. This lecture analyses the three-dimensional flow in axial compressors and turbines, so that, by appreciation of the factors involved, possible methods of improving the performance can readily be investigated. The origin of secondary flow is first examined for the simple case of a straight cascade. The physical nature of the flow, and theories which enable quantitative estimates to be made, are discussed at some length. Following this, the three-dimensional flow in an annulus with a stationary blade row is examined, and, among other things, the influence of radial equilibrium on the flow pattern is noted. All physical restrictions are then removed, and the major factors governing the three-dimensional flow in an actual machine are investigated as far as is possible with existing information, particular attention being paid to the influence of a non-uniform velocity profile, tip clearance, shrouding, and boundary layer displacement. Finally the various empirical factors used in design are discussed, and the relationships between them established.

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