Investigations of Transonic Turbine Cascade With High Stagger and Low Solidity

1979 ◽  
Author(s):  
M. Inoue ◽  
S. Yamaguchi ◽  
M. Kuroumaru
Keyword(s):  
Transonic Flow ◽  
Laval Nozzle ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Chord Length ◽  
Turbine Cascade ◽  
Trailing Edge ◽  
Time Marching ◽  
Shock System ◽  
Transonic Turbine

In order to clarify the transonic flow characteristics of a turbine cascade with high stagger, low solidity and small deflections, experimental studies were carried out by shortening the chord length of a “Laval-nozzle shaped” blade with thick trailing edge. The behavior of the shock system depends on the amount of overlap between the blades. The relations between the behavior and the performances were discussed in detail. The results may be applied to more standard sections. Lastly, validity of an appropriate time marching analysis for the highly staggered cascade was investigated by comparing with the experiment.

The Aerodynamics of Trailing-Edge-Cooled Transonic Turbine Blades: Part 2 — Theoretical and Computational Approach

1997 ◽  
Author(s):  
Mathias Deckers ◽  
John D. Denton
Keyword(s):  
Transonic Flow ◽  
Theoretical Study ◽  
Computational Study ◽  
Control Volume ◽  
Turbine Blades ◽  
Computational Approach ◽  
Trailing Edge ◽  
Time Marching ◽  
Transonic Turbine ◽  
Volume Method

A theoretical and computational study into the aerodynamics of trailing-edge-cooled transonic turbine blades is described in this part of the paper. The theoretical study shows that, for unstaggered blades with coolant ejection, the base pressure and overall loss can be determined exactly by a simple control volume analysis. This theory suggests that a thick, cooled trailing edge with a wide slot can be more efficient than a thin, solid trailing edge. An existing time-marching finite volume method is adapted to calculate the transonic flow with trailing edge coolant ejection on a structured, quasi-orthogonal mesh. Good overall agreement between the present method, inviscid and viscous, and experimental evidence is obtained.

Experimental and Numerical Investigation on the Performance of a Family of Three HP Transonic Turbine Blades

2004 ◽  
Author(s):  
D. Corriveau ◽  
S. A. Sjolander
Keyword(s):  
Flow Velocity ◽  
Turbine Blades ◽  
Suction Side ◽  
Experimental Results ◽  
Base Pressure ◽  
Suction Surface ◽  
Trailing Edge ◽  
Lower Base ◽  
Shock System ◽  
Transonic Turbine

Experimental results concerning the performance of three high-pressure (HP) transonic turbine blades having fore-, aft- and mid-loadings have been presented previously by Corriveau and Sjolander [1]. Results from that study indicated that by shifting the loading towards the rear of the airfoil, improvements in loss performance of the order of 20% could be obtained near the design Mach number. In order to gain a better understanding of the underlying reasons for the improved loss performance of the aft-loaded blade, additional measurements were performed on the three cascades. Furthermore, 2-D numerical simulations of the cascade flow were performed in order to help in the interpretation of the experimental results. Based on the analysis of additional wake traverse data and base pressure measurements combined with the numerical results, it was found that the poorer loss performance of the baseline mid-loaded profile compared to the aft-loaded blade could be traced back to the former’s higher rear suction side curvature. The presence of higher rear suction surface curvature resulted in higher flow velocity in that region. Higher flow velocity at the trailing edge in turn contributed to reducing the base pressure. The lower base pressure at the trailing edge resulted in a stronger trailing edge shock system for the mid-loaded blade. This shock system increased the losses for the mid-loaded baseline profile when compared to the aft-loaded profile.

Experimental and numerical investigations of trailing edge injection in a transonic turbine cascade

2019 ◽  
Vol 92 ◽  
pp. 258-268 ◽  
Author(s):  
Jie Gao ◽  
Ming Wei ◽  
Weiliang Fu ◽  
Qun Zheng ◽  
Guoqiang Yue
Keyword(s):  
Turbine Cascade ◽  
Trailing Edge ◽  
Numerical Investigations ◽  
Transonic Turbine

A Simple Procedure to Compute Losses in Transonic Turbines Cascades

1985 ◽  
Author(s):  
Francesco Martelli ◽  
Alberto Boretti
Keyword(s):  
Transonic Flow ◽  
Simple Procedure ◽  
Turbine Blades ◽  
Wave Interaction ◽  
Integral Boundary ◽  
Shock Wave Interaction ◽  
Time Requirements ◽  
Time Marching ◽  
Shock System ◽  
Marching Method

The prediction of losses in transonic flow in turbines is an important step in the design of turbine stages, but at the same time requirements of simplicity and speed are needed to allow the work of designers. The paper presents a procedure developed to match this goal. It uses classical codes, experimental correlations and simple geometrical models of the shock system. The result of a time marching method with standard mesh is used to run an Integral Boundary layer calculation in which shock wave interaction effects have been included. The shock system is made up of this information plus empirical correlation and a suitable procedure. A mixing calculation is then performed to get the downstream total pressure. The method has been tested with various kinds of turbine blades of which losses and data for calculations have been published. The results are quite good and the procedure appears simple and fast.

Navier–Stokes Solution for Steady Two-Dimensional Transonic Cascade Flows

1988 ◽  
Vol 110 (3) ◽  
pp. 339-346 ◽  
Author(s):  
O. K. Kwon
Keyword(s):  
Stokes Equations ◽  
Solution Procedure ◽  
Curvilinear Coordinates ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Turbine Cascade ◽  
Navier Stokes Equations ◽  
Time Marching ◽  
Transonic Turbine ◽  
Transonic Cascade

A robust, time-marching Navier–Stokes solution procedure based on the explicit hopscotch method is presented for solution of steady, two-dimensional, transonic turbine cascade flows. The method is applied to the strong conservation form of the unsteady Navier–Stokes equations written in arbitrary curvilinear coordinates. Cascade flow solutions are obtained on an orthogonal, body-conforming “O” grid with the standard k–ε turbulence model. Computed results are presented and compared with experimental data.

scholarly journals The Aerodynamics of Trailing-Edge-Cooled Transonic Turbine Blades: Part 1 — Experimental Approach

1997 ◽  
Author(s):  
Mathias Deckers ◽  
John D. Denton
Keyword(s):  
Turbine Blades ◽  
Base Pressure ◽  
Stagnation Temperature ◽  
Trailing Edge ◽  
Static Pressure Distribution ◽  
Discernible Effect ◽  
Two Dimensional Flow ◽  
Shock System ◽  
Flow Through ◽  
Transonic Turbine

The research presented in this part of the paper involved a detailed experimental study of the flow through transonic turbine blading with trailing edge coolant ejection. The tests were carried out on (nearly) flat plate models representing the region of uncovered turning downstream of the throat. The investigation focused on the aerodynamic aspects associated with trailing edge ejection in steady two-dimensional flow over a range of exit Mach numbers, coolant pressure ratios and temperature ratios. The experiments showed that the simple existence of the coolant cavity leads to a substantial change of the flow field in the near wake. Consequently, the slotted unblown base was found to have considerably less loss than the solid one. The effect of coolant ejection is shown to cause a substantial increase in base pressure and reduction in overall loss. The surface static pressure distribution and boundary layers were affected by the coolant in two ways: directly from downstream, via the base pressure, and indirectly through a changed trailing edge shock system. However, the coolant stagnation temperature ratio was found to have no discernible effect on the base pressure and loss.

scholarly journals Simulation of Trailing Edge Vortex Shedding in a Transonic Turbine Cascade

1996 ◽  
Author(s):  
Tom C. Currie ◽  
William E. Carscallen
Keyword(s):  
Vortex Shedding ◽  
Navier Stokes ◽  
Numerical Dissipation ◽  
Turbine Cascade ◽  
Trailing Edge ◽  
Edge Vortex ◽  
Transonic Turbine ◽  
Exit Mach Number ◽  
Good Agreement

Mid-span losses in the NRC transonic turbine cascade peak at an exit Mach number (M2) of ∼1.0 and then decrease by ∼40% as M2 is increased to the design value of 1.16. Since recent experimental results suggest that the decrease may be related to a reduction in the intensity of trailing edge vortex shedding, both steady and unsteady quasi-3D Navier-Stokes simulations have been performed with a highly refined (unstructured) grid to determine the role of shedding. Predicted shedding frequencies are in good agreement with experiment, indicating the blade boundary layers and trailing edge separated free shear layers have been modelled satisfactorily, but the agreement for base pressures is relatively poor, probably due largely to false entropy created downstream of the trailing edge by numerical dissipation. The results emphasize the importance of accounting for the effect of vortex shedding on base pressure and loss.

scholarly journals Viscous Flow Computations in Turbomachine Cascades

1990 ◽  
Author(s):  
P.-A. Chevrin ◽  
C. Vuillez
Keyword(s):  
Stokes Equations ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Turbine Cascade ◽  
Compressor Cascade ◽  
Navier Stokes Equations ◽  
Transonic Compressor ◽  
Different Types ◽  
Time Marching ◽  
Transonic Turbine

Accurate prediction of the flow in turbomachinery requires numerical solution of the Navier-Stokes equations. A two-dimensional Navier-Stokes solver developed at ONERA for the calculation of the flow in turbine and compressor cascades was adapted at SNECMA to run on different types of grid. The solver uses an explicit, time-marching, finite-volume technique, with a multigrid acceleration scheme. A multi-domain approach is used to handle difficulties due to the geometry of the flow. An H-C grid was used in the calculations. Two turbulence models, based on the mixing length approach, were used. The flow in a transonic compressor cascade, a subsonic and a transonic turbine cascade were computed. Comparison with experiments is presented.

Simulation of Trailing Edge Vortex Shedding in a Transonic Turbine Cascade

1998 ◽  
Vol 120 (1) ◽  
pp. 10-19 ◽  
Author(s):  
T. C. Currie ◽  
W. E. Carscallen
Keyword(s):  
Vortex Shedding ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Numerical Dissipation ◽  
Turbine Cascade ◽  
Trailing Edge ◽  
Edge Vortex ◽  
Transonic Turbine ◽  
Exit Mach Number

Midspan losses in the NRC transonic turbine cascade peak at an exit Mach number (M2) of ~1.0 and then decrease by ~40 percent as M2 is increased to the design value of 1.16. Since recent experimental results suggest that the decrease may be related to a reduction in the intensity of trailing edge vortex shedding, both steady and unsteady quasi-three-dimensional Navier–Stokes simulations have been performed with a highly refined (unstructured) grid to determine the role of shedding. Predicted shedding frequencies are in good agreement with experiment, indicating the blade boundary layers and trailing edge separated free shear layers have been modeled satisfactorily, but the agreement for base pressures is relatively poor, probably due largely to false entropy created downstream of the trailing edge by numerical dissipation. The results nonetheless emphasize the importance of accounting for the effect of vortex shedding on base pressure and loss.

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