The Computation of Transonic Flow Through Two-Dimensional Gas Turbine Cascades

1971 ◽  
Author(s):  
P. W. McDonald
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Transonic Flow ◽  
Equations Of Motion ◽  
Two Dimensional ◽  
Airfoil Surface ◽  
Pressure Distributions ◽  
Flow Through ◽  
Turbine Cascades ◽  
Definition Of

Steady transonic flow through two-dimensional gas turbine cascades is efficiently predicted using a time-dependent formulation of the equations of motion. An integral representation of the equations has been used in which subsonic and supersonic regions of the flow field receive identical treatment. Mild shock structures are permitted to develop naturally without prior knowledge of their exact strength or position. Although the solutions yield a complete definition of the flow field, the primary aim is to produce airfoil surface pressure distributions for the design of aerodynamically efficient turbine blade contours. In order to demonstrate the accuracy of this method, computed airfoil pressure distributions have been compared to experimental results.

Numerical Solution of Inviscid Two-Dimensional Transonic Flow Through a Cascade

1987 ◽  
Vol 109 (1) ◽  
pp. 108-113
Author(s):  
J. Forˇt ◽  
K. Kozel
Keyword(s):  
Experimental Data ◽  
Weak Solution ◽  
Numerical Solution ◽  
Transonic Flow ◽  
Numerical Procedure ◽  
Numerical Results ◽  
Two Dimensional ◽  
System Of Difference Equations ◽  
Flow Through ◽  
Turbine Cascades

The paper presents a method of numerical solution of transonic potential flow through plane cascades with subsonic inlet flow. The problem is formulated as a weak solution with combined Dirichlet’s and Neumann’s boundary conditions. The numerical procedure uses Jameson’s rotated difference scheme and the SLOR technique to solve a system of difference equations. Numerical results of transonic flow are compared with experimental data and with other numerical results for both compressor and turbine cascades near choke conditions.

Back Flow in Turbines of Nuclear Closed-Cycle Gas Turbine Plants in Case of Circuit Pipe Rupture

1975 ◽  
Vol 97 (2) ◽  
pp. 189-194 ◽  
Author(s):  
K. Bammert ◽  
P. Zehner
Keyword(s):  
Gas Turbine ◽  
Rotor Blade ◽  
Back Flow ◽  
Blade Tip ◽  
Stator Blade ◽  
Flow Through ◽  
High Temperature Reactor ◽  
Turbine Cascades ◽  
Characteristic Features ◽  
Safety Considerations

For operation of a gas turbine in single-cycle arrangement with a high-temperature reactor, rupture of a main circuit pipe has to be included in the safety considerations. In the event of such an accident there may be a back flow through the turbo machines or a forward flow up to the choking limit. This paper is a report on tests carried out in a two-dimensional cascade wind tunnel on turbine cascades under back flow conditions. By the example of three selected representative cascades the characteristic features in turbine cascades with back flow are discussed. These cascades are a rotor blade tip section with aerofoil-like profiles and a wide pitch, a stator blade or rotor blade mean section with an usual deflection and a rotor blade root section with a narrow pitch and a large deflection.

Effect of Prediffuser Angle on the Static Pressure Recovery in Flow Through Casing-Liner Annulus of a Gas Turbine Combustor at Various Swirl Levels

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Prakash Ghose ◽  
Amitava Datta ◽  
Achintya Mukhopadhyay
Keyword(s):  
Gas Turbine ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Recovery ◽  
Gas Turbine Combustor ◽  
Pressure Losses ◽  
Pressure Distributions ◽  
Inlet Swirl ◽  
Flow Through ◽  
The Ideal

A numerical study has been performed in an axisymmetric diffuser followed by a casing-liner annulus of a typical gas turbine combustor to analyze the flow structure and pressure recovery in the geometry. Static pressure recovery in a gas turbine combustor is important to ensure high pressure of air around the liner. However, the irreversible pressure losses reduce the static pressure recovery from the ideal value. The presence of swirl in the flow from compressor and prediffuser geometry before the dump diffuser influences the flow pattern significantly. In this study, flow structures are numerically predicted with different prediffuser angles and inlet swirl levels for different dump gaps. Streamline distributions and pressure plots on the casing and liner walls are analyzed. Static pressure recovery coefficients are obtained from the pressure distributions across the combustor. The effect of dump gap on the static pressure recovery has also been evaluated. It is observed that the best static pressure recovery can be obtained at optimum values of inlet swirl level and prediffuser angle. Dump gap is found to have significant influence on the static pressure recovery only at small prediffuser angle.

The Transonic Flow Through a Plane Turbine Cascade as Measured in Four European Wind Tunnels

1986 ◽  
Vol 108 (2) ◽  
pp. 277-284 ◽  
Author(s):  
R. Kiock ◽  
F. Lehthaus ◽  
N. C. Baines ◽  
C. H. Sieverding
Keyword(s):  
Transonic Flow ◽  
High Speed ◽  
Turbine Rotor ◽  
Wind Tunnels ◽  
Test Results ◽  
Turbine Rotor Blade ◽  
Pressure Distributions ◽  
Order Of Magnitude ◽  
Blade Section ◽  
Flow Through

Reliable cascade data are esssential to the development of high-speed turbomachinery, but it has long been suspected that the tunnel environment influences the test results. This has now been investigated by testing one plane gas turbine rotor blade section in four European wind tunnels of different test sections and instrumentation. The Reynolds number of the transonic flow tests was Re2 = 8 × 105 based on exit flow conditions. The turbulence was not increased artificially. A comparison of results from blade pressure distributions and wake traverse measurements reveals the order of magnitude of tunnel effects.

Time-Marching Analysis of Steady Transonic Flow in Turbomachinery Cascades Using the Hopscotch Method

1983 ◽  
Vol 105 (2) ◽  
pp. 272-279 ◽  
Author(s):  
R. A. Delaney
Keyword(s):  
Experimental Data ◽  
Euler Equations ◽  
Transonic Flow ◽  
Numerical Scheme ◽  
Curvilinear Coordinates ◽  
Two Dimensional ◽  
Analysis Method ◽  
Time Marching ◽  
Turbine Cascades ◽  
Turbomachinery Cascades

A rapid, time-marching, numerical scheme based on the hopscotch method is presented for solution of steady, two-dimensional, transonic flow in turbomachinery cascades. The scheme is applied to the strong-conservation form of the unsteady Euler equations written in arbitrary curvilinear coordinates. Cascade solutions are obtained on an orthogonal, body-centered coordinate system. Numerical solution results for two turbine cascades are presented and compared with experimental data to demonstrate the accuracy and computational efficiency of the analysis method.

Similarity Law of Transonic Flow Fields Around Cascades

1981 ◽  
Author(s):  
S. Zhou ◽  
M. Y. Shen ◽  
B. Z. Lin
Keyword(s):  
Flow Field ◽  
Transonic Flow ◽  
Flow Fields ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Two Dimensional ◽  
Von Karman ◽  
The Law ◽  
Von Kármán ◽  
Similarity Law

In order to extend the usage range of a cascade having excellent aerodynamic performance, it is beneficial to investigate the similarity between different flow fields. Von Karman gave transonic similarity law of two-dimensional isolated airfoils many years ago. However, the law of cascades is still different from that of airfoils. This paper points out that, to guarantee similarity between two flow fields around cascades, it is necessary that five corresponding transonic similarity parameters must be kept equal. Also some examples have been presented in this paper for demonstration. They indicate that the similarity law will help us to obtain rapidly many similar transonic flow fields around cascades at different operating conditions from a known flow field around a given cascade.

Effect of Blade Curving on the Flow Field Structure in an Annular Turbine Cascade

1999 ◽  
Author(s):  
Yanping Song ◽  
Zhongqi Wang ◽  
Wencai Lu ◽  
Wenyuan Xu
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Field Structure ◽  
Turbine Cascade ◽  
Three Dimensional Flow ◽  
Surface Pressure Distribution ◽  
Pressure Distributions ◽  
Curved Blade ◽  
Turbine Cascades ◽  
Annular Cascade

In the present paper, two annular turbine cascades have been tested in order to investigate the effect of blade curving on the structure of the three-dimensional flow field. The blades in all two cascades have the same section and they are stacked on the trailing edge that is straight in the first and a circular arc in the second. Detailed cascade tests consisted of passage flow parameter traverses, blade and endwall surface pressure distribution, and flow visualization. The results show that the flow field is three dimensional in an annular cascade with different pressure distributions near two endwalls, whose direct effect is amplified through the creation of passage vortices of different scale and strength at hub and tip. Blade curving changes the pressure field completely, in axial, pitchwise and spanwise directions. The combined effect of 3-D characteristics and blade curving causes significant differences of flow field structure in curved blade.

Experimental Investigation and Mathematical Modeling of Clearance Brush Seals

1998 ◽  
Vol 120 (3) ◽  
pp. 573-579 ◽  
Author(s):  
M. T. Turner ◽  
J. W. Chew ◽  
C. A. Long
Keyword(s):  
Radial Pressure ◽  
Experimental Program ◽  
Cfd Analysis ◽  
Axial Pressure ◽  
Pressure Distributions ◽  
Brush Seal ◽  
Flow Through ◽  
Definition Of ◽  
Resistance Coefficients ◽  
Nonlinear Resistance

In this paper, an experimental program and a CFD based mathematical model using a brush seal at two bristle to rotor clearances (0.27 mm and 0.75 mm) are presented. The experimental program examined the radial pressure distributions along the backing ring, the axial pressure distribution along the rotor, and the mass flow through the seal through a range of pressure ratios while exhausting to atmosphere. The results from this experimental program have been used to further calibrate a CFD-based model. This model treats the bristle pack as an axisymmetric, anisotropic porous region, and is calibrated by the definition of nonlinear resistance coefficients in three orthogonal directions. The CFD analysis calculates the aerodynamic forces on the bristles, which are subsequently used in a separate program to estimate the bristle movements, stresses, and bristle and rotor loads. The analysis shows that a brush seal with a build clearance produces a very different flow field within the bristle pack to one with an interference, and the need to understand the bulk movements of the bristles. These are shown to be affected by the level of friction between the bristles and the backing ring, which has an important effect on the bristles wear and seal leakage characteristics.

Theoretical Investigation of Pressure Distributions Along the Surfaces of a Thin Blade of Arbitrary Geometry of a Two-Dimensional Centrifugal Pump Impeller

1977 ◽  
Vol 99 (3) ◽  
pp. 531-539 ◽  
Author(s):  
T. C. Mohana Kumar ◽  
Y. V. N. Rao
Keyword(s):  
Centrifugal Pump ◽  
Numerical Procedure ◽  
Two Dimensional ◽  
Arbitrary Geometry ◽  
Pump Impeller ◽  
Pressure Distributions ◽  
Blade Thickness ◽  
Hydrodynamic Method ◽  
Flow Through ◽  
Centrifugal Pump Impeller

The flow through a two-dimensional centrifugal pump impeller with thin blades of arbitrary geometry is investigated using the hydrodynamic method of singularities. A theoretical analysis is developed to determine the impeller head and pressure distributions along the blade surfaces. The convergence of the numerical procedure is discussed. These results are compared with the theoretical and experimental results reported by Acosta. There is excellent agreement between the theoretical values of the impeller head and the pressure distributions obtained by both methods. Discrepancies in the theoretical and experimental pressure distributions are attributed to the effects of viscosity, inlet turn, blade thickness and inlet stall which are neglected in the analysis.

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