An Experimental Investigation Into the Effect of Wakes on the Unsteady Turbine Rotor Flow

1985 ◽  
Vol 107 (2) ◽  
pp. 458-465 ◽  
Author(s):  
A. Binder ◽  
W. Fo¨rster ◽  
H. Kruse ◽  
H. Rogge
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Air Turbine ◽  
Flow Phenomena ◽  
Unsteady Effects ◽  
Yaw Angle ◽  
Insight Into ◽  
Rotor Flow

Detailed measurements were carried out near and within a turbine rotor using the Laser-2-Focus velocimeter. Testing was performed in a single stage cold air turbine at off-design conditions with a stator outlet Mach number of approximately 0.8. Instantaneous and averaged results of the velocity, the yaw angle, and the turbulence intensity provided information on the rotor flow field. This report describes the periodical and random unsteady effects of the stator wakes impinging on the rotor blades. In particular the constant unsteadiness contours clearly disclose the development of the wakes cut by the rotor blades. The objective of the study was to gain more insight into unsteady flow phenomena affecting losses, heat transfer, and related problems.

scholarly journals Tip Leakage Flow in a Linear Turbine Cascade

1988 ◽  
Vol 110 (1) ◽  
pp. 18-26 ◽  
Author(s):  
J. Moore ◽  
J. S. Tilton
Keyword(s):  
Heat Transfer ◽  
Potential Flow ◽  
Pressure Rise ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Vena Contracta

An experimental and analytical study of flow in the tip clearance gap of a linear turbine rotor blade cascade has been performed. Measurements of wall static pressures and flow velocities are used to verify a flow model involving a vena contracta, near the tip gap entrance, followed by flow mixing to fill the gap. A frequently referenced potential flow theory for flow into a tip gap is found to be in error and the correct theory is shown to model the unloading along the pressure surface of the blade and the endwall static pressure distribution up to the vena contracta accurately. A combined potential flow and mixing model accounts for the pressure rise in the tip gap due to mixing. Turbine tip heat transfer is also discussed and a correlation of local heat transfer rates for essentially incompressible flow over unshrouded turbine rotor blades is presented.

Measurements and Predictions of Heat Transfer on Rotor Blades in a Transonic Turbine Cascade

2004 ◽  
Vol 126 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Paul W. Giel ◽  
Robert J. Boyle ◽  
Ronald S. Bunker
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Thin Foil ◽  
Reynolds Numbers ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Maximum Point ◽  
Stagnation Region ◽  
Design Point ◽  
Laminar To Turbulent Transition

Detailed heat transfer measurements and predictions are given for a power generation turbine rotor with 127 deg of nominal turning and an axial chord of 130 mm. Data were obtained for a set of four exit Reynolds numbers comprised of the facility maximum point of 2.50×106, as well as conditions which represent 50%, 25%, and 15% of this maximum condition. Three ideal exit pressure ratios were examined including the design point of 1.443, as well as conditions which represent −25% and +20% of the design value. Three inlet flow angles were examined including the design point and ±5deg off-design angles. Measurements were made in a linear cascade with highly three-dimensional blade passage flows that resulted from the high flow turning and thick inlet boundary layers. Inlet turbulence was generated with a blown square bar grid. The purpose of the work is the extension of three-dimensional predictive modeling capability for airfoil external heat transfer to engine specific conditions including blade shape, Reynolds numbers, and Mach numbers. Data were obtained by a steady-state technique using a thin-foil heater wrapped around a low thermal conductivity blade. Surface temperatures were measured using calibrated liquid crystals. The results show the effects of strong secondary vortical flows, laminar-to-turbulent transition, and also show good detail in the stagnation region.

A Novel Cooling Method for Turbine Rotor-Stator Rim Cavities Affected by Mainstream Ingress

2004 ◽  
Vol 127 (4) ◽  
pp. 798-806 ◽  
Author(s):  
Y. Okita ◽  
M. Nishiura ◽  
S. Yamawaki ◽  
Y. Hironaka
Keyword(s):  
Gas Flow ◽  
Numerical Study ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Significant Advance ◽  
Axial Distribution ◽  
Cooling Effectiveness ◽  
Cooling Flow ◽  
Cooling Method ◽  
Flow Phenomena

A combined experimental and numerical study of interaction between cooling flow and mainstream gas flow in a turbine rotor-stator rim cavity is reported. Particular emphasis is put on the flow phenomena in a rim cavity downstream of rotor blades. The experiments are conducted on a rig simulating an engine HP-turbine in which cooling effectiveness distributions as well as velocities, turbulence quantities, pressure, and temperature profiles are measured. Numerical calculation, especially at a full 3D, unsteady solution level, can lead to satisfactory predictions in fluid and mass transfer inside the cavity. Both experimental and numerical results indicate that large turbulence stresses near the rotor disk intensify turbulent diffusion across the cavity and consequently axial distribution of the cooling effectiveness inside the cavity becomes uniform. In order to obtain an adequate distribution of cooling effectiveness across the rim cavity and to suppress the turbulence level near the rotor surface for more efficient cooling, a novel cooling method is developed using numerical simulation. The disk-front and -rear cavities are then redesigned according to the new cooling strategy and integrated in the test rig. Experimental results verify a significant advance in cooling performance with the new method.

An Experimental Study of Local and Mean Heat Transfer in a Triangular-Sectioned Duct Rotating in the Orthogonal Mode

1984 ◽  
Vol 106 (3) ◽  
pp. 661-667 ◽  
Author(s):  
R. J. Clifford ◽  
W. D. Morris ◽  
S. P. Harasgama
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Reynolds Numbers ◽  
Local Heat ◽  
Turbine Rotor ◽  
Turbulent Pipe Flow ◽  
Rotor Blades ◽  
Noticeable Effect ◽  
Number Range ◽  
Selection Of

This paper presents a selection of experimental results that examines the influence of orthogonal-mode rotation on local and mean heat transfer in a triangular-sectioned duct with potential application to cooled turbine rotor blades. It is shown that Coriolis acceleration can have a beneficial influence on mean heat transfer relative to the nonrotating case at the lower range of turbulent pipe flow Reynolds numbers studied. Also, rotational buoyancy has been shown to have a noticeable effect over this same Reynolds number range in that progressively increasing buoyancy brings about an attendant reduction in heat transfer. As the Reynolds numbers are increased, say, beyond 30,000, buoyancy effects were found to have little influence on mean heat transfer over the speed range covered. Local axial variations in heat transfer along the duct were also measured, and severe reductions in local heat transfer were detected under certain operating circumstances.

Heat Transfer in a Rotating Square-Sectioned Channel Fitted With In-Line Ribs

Volume 1 ◽  
2004 ◽  
Author(s):  
A. W. Lees ◽  
J. M. J. Khamaj ◽  
W. D. Morris ◽  
S. W. Chang
Keyword(s):  
Heat Transfer ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Central Axis ◽  
Flow And Heat Transfer ◽  
Trailing Edges ◽  
Temperature Parameter ◽  
The Individual ◽  
Independent Parameters ◽  
Reduced Temperature

This investigation studies convective heat transfer in a square-sectioned duct that rotates about an axis perpendicular to the central axis of the duct. The leading and trailing sides of the duct are fitted with in-line ribs aligned at 45° to the central axis of the duct. The leading and trailing edges are heated and the two remaining sidewalls of the duct are adiabatic. Air is the coolant used and the direction of flow is in the radial outward direction. The duct simulates the flow and heat transfer that occurs in the passages of cooled turbine rotor blades. The presentation of results is in itself a non-trivial task as the heat transfer is a function of three independent parameters. It is shown how the performance of the section may be expressed in terms of a reduced temperature parameter and that this approach offers additional insight as compared to the conventional Nusselt number approach (which may be obtained by a simple transformation. The investigation has produced a range of experimental data to aid the validation of CFD codes designed to predict heat transfer in this class of rotating duct. Additionally empirical correlations for heat transfer on the leading and trailing edges are proposed that uncouple the individual effects of Coriolis forces and centripetal buoyancy.

Experimental and Numerical Analysis of Gas Turbine Blades With Different Internal Cooling Geometries

2009 ◽  
Author(s):  
M. Eifel ◽  
V. Caspary ◽  
H. Ho¨nen ◽  
P. Jeschke
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Base Flow ◽  
Internal Cooling ◽  
Turbine Rotor Blade ◽  
Flow Phenomena ◽  
Sst Turbulence Model

This paper presents the effects of major geometrical modifications to the interior of a convection cooled gas turbine rotor blade. The analysis of the flow is performed experimentally with flow visualization via paint injection into water whereas the flow and the heat transfer are investigated numerically with Ansys CFX utilizing the SST turbulence model. Two sets of calculations are carried out, one under the same conditions as the experiments and another according to realistic hot gas conditions with conjugate heat transfer. The aim is to identify flow phenomena altering the heat transfer in the blade and to manipulate them in order to reduce the thermal load of the material. The operating point of the geometric base configuration is set to Re = 50,000 at the inlet while for the modified geometries the pressure ratio is held constant compared to the base. Flow structures and heat transfer conditions are evaluated and are linked to specific geometric features. Among several investigated configurations one could be identified that leads to a cooling effectiveness 15% larger compared to the base.

Experimental and Numerical Analysis of Gas Turbine Blades With Different Internal Cooling Geometries

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
M. Eifel ◽  
V. Caspary ◽  
H. Hönen ◽  
P. Jeschke
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Turbine Rotor ◽  
Base Flow ◽  
Internal Cooling ◽  
Turbine Rotor Blade ◽  
Flow Phenomena ◽  
Sst Turbulence Model

This paper presents the effects of major geometrical modifications to the interior of a convection cooled gas turbine rotor blade. The analysis of the flow is performed experimentally with flow visualization via paint injection into water, whereas the flow and the heat transfer are investigated numerically with ANSYS CFX, utilizing the SST turbulence model. Two sets of calculations are carried out: one under the same conditions as the experiments and another according to realistic hot gas conditions with conjugate heat transfer. The aim is to identify flow phenomena altering the heat transfer in the blade and to manipulate them in order to reduce the thermal load of the material. The operating point of the geometric base configuration is set to Re=50,000 at the inlet while for the modified geometries, the pressure ratio is held constant compared with the base. Flow structures and heat transfer conditions are evaluated and are linked to specific geometric features. Among several investigated configurations one could be identified that leads to a cooling effectiveness 15% larger compared with the base.

scholarly journals Heat Transfer Measurements in Rectangular Channels With Orthogonal Mode Rotation

1990 ◽  
Author(s):  
W. D. Morris ◽  
G. Ghavami-Nasr
Keyword(s):  
Heat Transfer ◽  
Flow Direction ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Rotating Flow ◽  
Internal Cooling ◽  
Rectangular Channels ◽  
Flow Geometry

The influence of rotation on local heat transfer in a rectangular-sectioned duct has been experimentally studied for the case where the ductrotates about an axis orthogonal to its own central axis. The coolant used was air with the flow direction in the radially outwards direction. This rotating flow geometry is encountered in the internal cooling of gas turbine rotor blades.

Heat Transfer Measurements in Rectangular Channels With Orthogonal Mode Rotation

1991 ◽  
Vol 113 (3) ◽  
pp. 339-345 ◽  
Author(s):  
W. D. Morris ◽  
G. Ghavami-Nasr
Keyword(s):  
Heat Transfer ◽  
Flow Direction ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Turbine Rotor ◽  
Secondary Flows ◽  
Rotor Blades ◽  
Coolant Temperature ◽  
Internal Cooling ◽  
General Terms

The influence of rotation on local heat transfer in a rectangular-sectioned duct has been experimentally studied for the case where the duct rotates about an axis orthogonal to its own central axis. The coolant used was air with the flow direction in the radially outward direction. This rotating flow geometry is encountered in the internal cooling of gas turbine rotor blades. Local Nusselt number variations along the duct have been determined over the trailing and leading surfaces. In general terms Coriolis-induced secondary flows are shown to enhance local heat transfer over the trailing surface compared to a stationary duct forced convection situation. The converse is true on the leading surface where significant impediment to local heat transfer can occur. Centripetal buoyancy is shown to influence the heat transfer response with heat transfer being improved on both leading and trailing surfaces as the wall-to-coolant temperature difference is increased with other controlling parameters held constant. Correlating equations are proposed and the results compared with those of other workers in the field.

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