Numerical Investigation of Three-Dimensional Separation in Twisted Turbine Blade: The Influence of Endwall Boundary Layer State

2020 ◽  
pp. 133-149
Author(s):  
Gaurav Saxena ◽  
Arun K. Saha ◽  
Ritesh Gaur
Keyword(s):  
Boundary Layer ◽  
Numerical Investigation ◽  
Turbine Blade ◽  
Three Dimensional

Analysis and Prediction of Transonic Turbine Blade Losses

1991 ◽  
Author(s):  
C. L. S. Farn ◽  
D. K. Whirlow ◽  
S. Chen
Keyword(s):  
Boundary Layer ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Variable Approach ◽  
Transonic Turbine ◽  
Steam Turbine Blades ◽  
Turbine Blade Design ◽  
Empirical Approaches ◽  
Mixing Losses

The use of simple computational means to determine the performance of cascades of turbine blades is attractive because it can quickly and economically yield results that can be used for optimization of classes of blades. Fully viscous flow computations are not at the point where they are economical for use in a routine way, and most computational methods lack the resolution to determine shock losses in the transonic flow regime. There is still a need for approaches that combine computation and empiricism. We describe approaches that combine quasi-three dimensional inviscid codes and boundary layer methods for blade passage flow with empirical approaches for shock losses and base pressure deficits to predict the losses in cascades of blades. Downstream mixing losses are handled by a distributed variable approach that uses the inviscid and boundary layer results to determine the distribution of variables at the trailing edge plane. The method gives accurate predictions for the set of distinctly different steam turbine blades for which it was run, and forms the basis for the development of rule-based turbine blade design.

An Experimental Study of Endwall and Airfoil Surface Heat Transfer in a Large Scale Turbine Blade Cascade

1980 ◽  
Vol 102 (2) ◽  
pp. 257-267 ◽  
Author(s):  
R. A. Graziani ◽  
M. F. Blair ◽  
J. R. Taylor ◽  
R. E. Mayle
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbine Blade ◽  
Large Scale ◽  
Dominant Role ◽  
Three Dimensional ◽  
Surface Flow ◽  
Airfoil Surface ◽  
Engine Operation ◽  
Blade Cascade

Local rates of heat transfer on the endwall, suction, and pressure surfaces of a large scale turbine blade cascade were measured for two inlet boundary layer thicknesses and for a Reynolds number typical of gas turbine engine operation. The accuracy and spatial resolution of the measurements were sufficient to reveal local variations of heat transfer associated with distinct flow regimes and with regions of strong three-dimensional flow. Pertinent results of surface flow visualization and pressure measurements are included. The dominant role of the passage vortex, which develops from the singular separation of the inlet boundary layer, in determining heat transfer at the endwall and at certain regions of the airfoil surface is illustrated. Heat transfer on the passage surfaces is discussed and measurements at airfoil midspan are compared with current finite difference prediction methods.

Numerical Investigation of the Secondary Flow of a Transonic Turbine Stage Using Various Turbulence Closures

2005 ◽  
Author(s):  
Rene Pecnik ◽  
Paul Pieringer ◽  
Wolfgang Sanz
Keyword(s):  
Boundary Layer ◽  
Secondary Flow ◽  
Numerical Investigation ◽  
Three Dimensional ◽  
Boundary Layer Transition ◽  
Numerical Code ◽  
Turbine Stage ◽  
Layer Transition ◽  
Transonic Turbine ◽  
Flow Effects

The accurate numerical simulation of the flow through turbine stages strongly depends on the proper prediction of turbulence phenomena. Especially investigations of heat transfer, skin friction, flow separation and secondary flow effects demand a reliable simulation of the turbulence respectively laminar to turbulent boundary layer transition. This paper presents a steady state three-dimensional numerical investigation of a transonic turbine guide vane at flow conditions similar to modern highly loaded gas turbines. At the Institute for Thermal Turbomachinery and Machine Dynamics extensive experimental investigations of the three dimensional flow trough this turbine stage were done to gain a better understanding of the flow physics and to verify computational results. The applied numerical code, which was developed at the institute, solves the Reynolds-averaged Navier-Stokes equations using a time-iterative finite volume method. Turbulence is modeled with the one equation model of Spalart and Allmaras, the two equation SST k-ω model of Menter and the V2F model of Durbin, the latter model is also able to capture boundary layer transition to turbulence. The objective of this paper is to compare the numerical results with experimental data and to figure out the impact of the different turbulence models on secondary flow effects.

A three-dimensional laminar boundary-layer calculation

1967 ◽  
Vol 28 (4) ◽  
pp. 769-792 ◽  
Author(s):  
W. H. H. Banks
Keyword(s):  
Boundary Layer ◽  
Boundary Conditions ◽  
Saddle Point ◽  
Numerical Investigation ◽  
Laminar Boundary Layer ◽  
Three Dimensional ◽  
Outer Edge ◽  
Developable Surface ◽  
Governing Equations ◽  
Independent Variables

Results are presented of a preliminary numerical investigation into a three-dimensional laminar boundary layer. It is assumed that the flow is over a developable surface and the boundary conditions at the outer edge of the layer are chosen to be u = U0 + xU1, v = yV1. This choice enables the governing equations to be written in terms of two, and not three, independent variables, viz. x and z. However, the three-dimensionality of the problem gives rise to a coupling of the equations which, not unnaturally, is still present after the elimination of y.For appropriate values of U1 and V1 it is found possible to integrate the equations approximately from the ‘birth’ of the boundary layer (x = 0) right up to a saddle point of attachment. Calculations have already been made for flow at such attachment points and the comparison of the present results with them is extremely good.

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