VISUALIZATION OF FLOW THROUGH THE TURBINE BLADE CASCADE WITH OPTIMIZED STREAMWISE BOUNDARY LAYER FENCE

2012 ◽  
Vol 19 (1) ◽  
pp. 57-80 ◽  
Author(s):  
K. N. Kumar ◽  
Mukka Govardhan
Keyword(s):  
Boundary Layer ◽  
Turbine Blade ◽  
Blade Cascade ◽  
Flow Through

scholarly journals Solution of Turbine Blade Cascade Flow Using an Improved Panel Method

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Zong-qi Lei ◽  
Guo-zhu Liang
Keyword(s):  
Turbine Blade ◽  
Inviscid Flow ◽  
Panel Method ◽  
Experiment Data ◽  
Blade Cascade ◽  
Comparison With Experiment ◽  
Cascade Flow ◽  
Mesh Free ◽  
Blade Row ◽  
Flow Through

An improved panel method has been developed to calculate compressible inviscid flow through a turbine blade row. The method is a combination of the panel method for infinite cascade, a deviation angle model, and a compressibility correction. The resulting solution provides a fast flexible mesh-free calculation for cascade flow. A VKI turbine blade cascade is used to evaluate the method, and the comparison with experiment data is presented.

3-D Numerical Simulation of the Flow Through a Turbine Blade Cascade With Cooling Injection at the Leading Edge

1996 ◽  
Author(s):  
Dieter Bohn ◽  
Karsten Kusterer ◽  
Harald Schönenborn
Keyword(s):  
Numerical Simulation ◽  
Turbine Blade ◽  
Gas Turbines ◽  
Stokes Equations ◽  
Leading Edge ◽  
Body Region ◽  
Gas Temperature ◽  
Hot Gas ◽  
Blade Cascade ◽  
Flow Through

High process efficiencies and high power-weight ratios are two major requirements for the economic operation of present day gas turbines. This development leads to extremely high turbine inlet temperatures and adjusted pressure ratios. The permissible hot gas temperature is limited by the material temperature of the blade. Intensive cooling is required to guarantee an economically acceptable life of the components which are in contact with the hot gas. Although film-cooling has been successfully in use for a couple of years along the suction side and pressure side, problems occur in the vicinity of the stagnation point due to high stagnation pressures and opposed momentum fluxes. In this area basic investigations are necessary to achieve a reliable design of the cooled blade. In the present calculations, a code for the coupled simulation of fluid flow and heat transfer in solid bodies is employed. The numerical scheme works on the basis of an implicit finite volume method combined with a multi-block technique. The full, compressible 3-D Navier-Stokes equations are solved within the fluid region and the Fourier equation for beat conduction is solved within the solid body region. An elliptic grid generator is used for the generation of the structured computational grid, which is a combination of various C-type and H-type grids. Results of a 3-D numerical simulation of the flow through a turbine blade cascade with and without cooling ejection at the leading edge through two slots are presented. The results are compared with 2-D numerical simulations and experimental results. It is shown that the distribution of the coolant on the blade surface is influenced by secondary flow phenomena which can not be taken into account by the 2-D simulations. Further coupled simulations with non-adiabatic walls in the leading edge region are performed with realistic temperature ratios and compared to the same case with adiabatic walls. It is shown that in the case of non-adiabatic walls the temperature on the blade wall is significantly lower than in the case of adiabatic walls.

Investigation of Wake Transport in a Turbine Blade Channel and Its Effect on the Boundary Layer Development

2009 ◽  
Author(s):  
Edyta Bijak-Bartosik ◽  
Witold Elsner
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Turbine Blade ◽  
Flow Direction ◽  
High Energy ◽  
Experimental Investigations ◽  
Small Scale ◽  
Minor Importance ◽  
Blade Cascade

The paper presents the results of experimental investigations of the wake migration within the blade passage of a steam turbine blade cascade. The upstream wakes were generated by the wheel with cylindrical bars rotating at the plane perpendicular to the flow direction. The bars diameter was chosen to match the loss of a representative turbine blade as well as the flow pattern at the inlet to the blade cascade. The measurements were performed with the use of hot-wire technique and double X-wire probe. The application of phase averaging allowed one to reproduce the wake convection. The wake movement was visualized by the perturbation velocity vectors and fluctuating components. Dense spatial resolution of measuring points allows for calculation and analysis of selected terms of turbulent kinetic energy transport equation. The results confirm experimental and numerical observations done already for high-loaded blade profiles, which reveal that as the wake passes through high spatial velocity gradient area the turbulent production appears. The turbulent production causes the increase of turbulent kinetic energy (TKE). The analysis confirms also that the convection is mainly responsible for the wake deformation and that the distortion of shape and wake width change especially at the edges of channel is caused by “jet effect”. It also was proved that the role and share of turbulent diffusion is of minor importance and only a slight increase of diffusion is observed in the rear part of the blade channel close to the suction side, where TKE production appears. It was shown also that transition starts not when the wake touches the boundary layer edge, but earlier under the high energy core of the impacting wake. The earlier start of the transition could be due to pressure coupling caused by high energetic small scale structures.

A Visual Study of Turbine Blade Pressure-Side Boundary Layers

1983 ◽  
Vol 105 (1) ◽  
pp. 47-52 ◽  
Author(s):  
L. S. Han ◽  
W. R. Cox
Keyword(s):  
Boundary Layer ◽  
Flow Visualization ◽  
Boundary Layers ◽  
Turbine Blade ◽  
High Speed ◽  
High Speed Photography ◽  
Pressure Side ◽  
Edge Region ◽  
Visual Study ◽  
Blade Cascade

Boundary layer characteristics on the pressure-side of a turbine airfoil were investigated experimentally in a three-blade cascade tunnel. The blades had a chord length of 21 in. to facilitate flow visualization and high-speed photography. The investigation revealed the existence of the Gortler’s vortices appearing in spurts in regions of severe curvature. In the trailing edge region, Karman vortices were detected and found to interact strongly with the Gortler’s vortices convected thereto.

Endwall Losses and Flow Unsteadiness in a Turbine Blade Cascade

1992 ◽  
Vol 114 (1) ◽  
pp. 191-197 ◽  
Author(s):  
L. Adjlout ◽  
S. L. Dixon
Keyword(s):  
Boundary Layer ◽  
Flow Visualization ◽  
Turbine Blade ◽  
Turbulence Intensity ◽  
Pressure Loss ◽  
Total Pressure ◽  
Free Stream ◽  
Total Pressure Loss ◽  
Pressure Distributions ◽  
Blade Cascade

The purpose of this paper is to describe an investigation of the flow within and downstream of a turbine blade cascade of high aspect ratio. A detailed experimental investigation into the changes in the endwall boundary layer in the cascade (100 deg camber angle) and total pressure loss downstream of the cascade was carried out. Flow visualization was used in order to obtain detailed photographs of the flow patterns on the endwall and for exhibiting the trailing edge vortices. Pressure measurements were carried out using a miniature cranked Kiel probe for three planes downstream of the cascade, with two levels of turbulence intensity of the free stream. Pressure distributions on the blade were measured at three spanwise locations, namely 4, 12, and 50 percent of the full span from the wall. Hot-wire anenometry combined with a spectrum analyzer program was used to determine the frequencies of the flow oscillations. The change in turbulence level of the free stream has a significant influence on all three pressure distributions. The striking difference between two of the pressure distributions is in the aft half of the suction side where the distribution with the lower turbulence intensity has the larger lift. The oil flow visualization reveals what appear to be two separation lines within the passage and are believed to originate from the horseshoe vortex. The pitchwise-averaged total pressure loss coefficient increases with the distance of the measurement plane downstream of the cascade blades. A substantial part of this loss increase close to the wall is caused by the high rate of shear of the new boundary layer on the endwall.

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.

scholarly journals A Visual Study of Turbine Blade Pressure-Side Boundary Layers

1982 ◽  
Author(s):  
Lit S. Han ◽  
W. R. Cox
Keyword(s):  
Boundary Layer ◽  
Flow Visualization ◽  
Boundary Layers ◽  
Turbine Blade ◽  
High Speed ◽  
High Speed Photography ◽  
Pressure Side ◽  
Edge Region ◽  
Visual Study ◽  
Blade Cascade

Boundary layer characteristics on the pressure-side of a turbine airfoil were investigated experimentally in a three-blade cascade tunnel. The blades had a chord length of 21 in. to facilitate flow visualization and high-speed photography. The investigation revealed the existence of the Gortler’s vortices appearing in spurts in regions of severe curvature. In the trailing edge region, Karman vortices were detected and found to interact strongly with the Gortler’s vortices convected thereto.

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