scholarly journals The Effect of Rotor Blade Thickness and Surface Finish on the Performance of a Small Axial Flow Turbine

1983 ◽  
Vol 105 (2) ◽  
pp. 377-382 ◽  
Author(s):  
R. J. Roelke ◽  
J. E. Haas
Keyword(s):  
Surface Finish ◽  
Rotor Blade ◽  
Axial Flow ◽  
Aerodynamic Performance ◽  
Rotor Blades ◽  
Performance Gain ◽  
Test Results ◽  
Blade Profile ◽  
Blade Thickness ◽  
Rough Surface Finish

An experimental investigation was conducted to determine the effect of blade profile inaccuracies and surface finish on the aerodynamic performance of a 11.15-cm tip dia turbine. The as-received cast rotor blades had a significantly thicker profile than the design intent and a fairly rough surface finish. Stage test results showed an increase of one point in efficiency by smoothing the surface finish and another three points by thinning the blade profiles to near the design profile. Most of the performance gain between the as-cast thick and the thinned rotor blades, both with the same surface finish, was attributed to reduced trailing edge losses of the recontoured blades.

Cold Blade Profile Generation Methodology for Compressor Rotor Blades Using FSI Approach

2017 ◽  
Author(s):  
Kirubakaran Purushothaman ◽  
Sankar Kumar Jeyaraman ◽  
Ajay Pratap ◽  
Kishore Prasad Deshkulkarni
Keyword(s):  
Aspect Ratio ◽  
Rotor Blade ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Blade Profile ◽  
Interaction Technique ◽  
Compressor Rotor ◽  
Blade Shape ◽  
Blade Geometry

This paper describes a methodology for obtaining correct blade geometry of high aspect ratio axial compressor blades during running condition taking into account of blade untwist and bending. It discusses the detailed approach for generating cold blade geometry for axial compressor rotor blades from the design blade geometry using fluid structure interaction technique. Cold blade geometry represents the rotor blade shape at rest, which under running condition deflects and takes a new operating blade shape under centrifugal and aerodynamic loads. Aerodynamic performance of compressor primarily depends on this operating rotor blade shape. At design point it is expected to have the operating blade shape same as the intended design blade geometry and a slight mismatch will result in severe performance deterioration. Starting from design blade profile, an appropriate cold blade profile is generated by applying proper lean and pre-twist calculated using this methodology. Further improvements were carried out to arrive at the cold blade profile to match the stagger of design profile at design operating conditions with lower deflection and stress for first stage rotor blade. In rear stages, thermal effects will contribute more towards blade deflection values. But due to short blade span, deflection and untwist values will be of lower values. Hence difference between cold blade and design blade profile would be small. This methodology can especially be used for front stage compressor rotor blades for which aspect ratio is higher and deflections are large.

Compressor Surge in Gas Turbines and Blast Furnace Compressor Installations

1965 ◽  
Vol 87 (2) ◽  
pp. 193-196
Author(s):  
R. A. Strub ◽  
P. Suter
Keyword(s):  
Fatigue Failure ◽  
Gas Turbines ◽  
Axial Flow ◽  
Rotor Blades ◽  
Test Results ◽  
Dynamic Stresses ◽  
Compressor Surge ◽  
Bending Stresses ◽  
Flow Compressor ◽  
Measured Pressure

The character of different surge cycles is described, and the corresponding influence on the dynamic loading of the blades of axial flow compressors is discussed. It is shown that essentially fatigue is governed by the rapidity of loading or unloading of the blading. Test results from an experimental 4-stage axial flow compressor showed that the induced dynamic stresses in the blades, which reach about three times the steady gas bending stresses, can lead to fatigue failure. Reference is also made to previous surge tests carried out on a gas turbine installation, which indicate that a good correlation can be expected between the calculated and the measured pressure distribution. Mention is made of the fatigue failure of the rotor blades of an industrial compressor submitted to a long period of intense surging.

Labyrinth Seal Leakage Tests: Tooth Profile, Tooth Thickness, and Eccentricity Effects

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Ahmed J. M. Gamal ◽  
John M. Vance
Keyword(s):  
Labyrinth Seal ◽  
Design Parameters ◽  
Working Fluid ◽  
Test Results ◽  
Blade Profile ◽  
Labyrinth Seals ◽  
Seal Design ◽  
Blade Thickness ◽  
Center Position ◽  
Blade Tip

The effects of two seal design parameters, namely blade (tooth) thickness and blade profile, on labyrinth seal leakage, as well as the effect of operating a seal in an off-center position, were examined through a series of nonrotating tests. Two reconfigurable seal designs were used, which enabled testing of two-, four-, and six-bladed see-through labyrinth seals with different geometries using the same sets of seal blades. Leakage and cavity pressure measurements were made on each of 23 seal configurations with a in.(101.6mm) diameter journal. Tests were carried out with air as the working fluid at supply pressures of up to 100psia (6.89bar). Experimental results showed that doubling the thickness of the labyrinth blades significantly influenced leakage, reducing the flow rate through the seals by up to 20%. Tests to determine the effect of blade-tip profile produced more equivocal results, with the results of experiments using each of the two test seal designs contradicting each other. Tests on one set of hardware indicated that beveling blades on the downstream side was most effective in limiting leakage, whereas tests on newer hardware with tighter clearances indicated that seals with flat-tipped blades were superior. The test results illustrated that both blade profile and blade thickness could be manipulated so as to reduce seal leakage. However, an examination of the effects of both factors together indicated that the influence of one of these parameters can, to some extent, negate the influence of the other (especially in cases with tighter clearances). finally, for all configurations tested, results showed that leakage through a seal increases with increased eccentricity and that this phenomenon was considerably more pronounced at lower supply pressures.

Presentation of a Blade-Design Method for Axial-Flow Turbines, Including Design and Test Results of a Typical Axial-Flow Stage

1960 ◽  
Vol 82 (1) ◽  
pp. 19-26
Author(s):  
F. Baumgartner ◽  
R. Amsler
Keyword(s):  
Design Method ◽  
Axial Flow ◽  
Rate Of Change ◽  
Rotor Blades ◽  
Test Results ◽  
Blade Loading ◽  
Blade Row ◽  
Consistent Manner ◽  
The Mean ◽  
Typical Design

A method is presented to determine the shape of stationary nozzle blades and rotor blades for an axial-flow-type turbine in a generally consistent manner based on the concept of aerodynamic blade loading. The mean blade load is a typical design parameter which predominantly determines the blade curvature. It depends in particular on the rate of change of momentum across the blade row. By applying the design method, airfoil shapes are obtained which satisfy the momentum requirements regardless of what blade-load distribution is assumed as long as the mean blade load remains constant. A specific application of the design method is described and test data are presented which show that good agreement between design goal and test results was achieved.

scholarly journals Investigation of Rotor Blade Roughness Effects on Turbine Performance

1992 ◽  
Author(s):  
J. L. Boynton ◽  
R. Tabibzadeh ◽  
S. T. Hudson
Keyword(s):  
Surface Finish ◽  
Space Shuttle ◽  
Power Level ◽  
Rotor Blades ◽  
Machining Process ◽  
Inlet Temperature ◽  
Test Results ◽  
Roughness Effects ◽  
Turbine Efficiency ◽  
Swirl Angle

The cold air test program was completed on the SSME (Space Shuttle Main Engine) HPFTP (High Pressure Fuel Turbopump) turbine with production nozzle vane rings and polished coated rotor blades with a smooth surface finish of 30 microinch (0.76 micrometer) RMS (Root Mean Square). The smooth blades were polished by an abrasive flow machining process. The test results were compared with the air test results from production rough coated rotor blades with a surface finish of up to 400 microinch (10.16 micrometer) RMS. Turbine efficiency was higher for the smooth blades over the entire range tested. Efficiency increased 2.1 percentage points at the SSME 104 percent RPL (Rated Power Level) condition. This efficiency improvement could reduce the SSME HPFTP turbine inlet temperature by 57 degrees Rankine (32 degrees Kelvin) increasing turbine durability. The turbine flow parameter increased and the mid-span outlet swirl angle became more axial with the smooth rotor blades.

scholarly journals Effect of Rotor Tip Clearance and Configuration on Overall Performance of a 12.77-Centimeter Tip Diameter Axial-Flow Turbine

1979 ◽  
Author(s):  
J. E. Haas ◽  
M. G. Kofskey
Keyword(s):  
Experimental Investigation ◽  
Rotor Blade ◽  
Axial Flow ◽  
Single Stage ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Blade Height ◽  
Overall Performance ◽  
Flow Reaction ◽  
The One

An extensive experimental investigation was made to determine the effect of varying the rotor tip clearance of a 12.77-cm-tip diameter, single-stage, axial-flow reaction turbine. In this investigation, the rotor tip clearance was obtained by use of a recess in the casing above the rotor blades and also by use of a reduced blade height. For the recessed casing configuration, the optimum rotor blade height was found to be the one where the rotor tip diameter was equal to the stator tip diameter. The tip clearance loss associated with this optimum recessed casing configuration was less than that for the reduced blade height configuration.

Rotor Blade Unsteady Aerodynamic Gust Response to Inlet Guide Vane Wakes

1993 ◽  
Vol 115 (1) ◽  
pp. 197-206 ◽  
Author(s):  
S. R. Manwaring ◽  
S. Fleeter
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Axial Flow ◽  
Unsteady Aerodynamics ◽  
Rotor Blades ◽  
Inlet Guide Vane ◽  
Unsteady Aerodynamic ◽  
Forcing Function ◽  
Reduced Frequency ◽  
Flow Compressor

A series of experiments is performed in an extensively instrumented axial flow research compressor to investigate the fundamental flow physics of wake-generated periodic rotor blade row unsteady aerodynamics at realistic values of the reduced frequency. Unique unsteady data are obtained that describe the fundamental unsteady aerodynamic gust interaction phenomena on the first-stage rotor blades of a research axial flow compressor generated by the wakes from the inlet guide vanes. In these experiments, the effects of steady blade aerodynamic loading and the aerodynamic forcing function, including both the transverse and chordwise gust components, and the amplitude of the gusts, are investigated and quantified.

Numerical Simulation and Flow Field Measurement of High Efficiency Axial-Flow Pump

2009 ◽  
Author(s):  
De-sheng Zhang ◽  
Wei-dong Shi ◽  
Bin Chen ◽  
Xing-fan Guan
Keyword(s):  
Rotor Blade ◽  
Radial Direction ◽  
High Efficiency ◽  
Static Pressure ◽  
Axial Flow ◽  
Rotor Blades ◽  
Experimental Results ◽  
Meridional Velocity ◽  
Axial Flow Pump ◽  
Flow Pump

In order to analyze the flow characteristics of a high efficiency axial-flow pump, the behavior of the flow in an adjustable axial-flow pump bas been analyzed by numerical simulations of the entire stage based on Fluent software. The prediction data shows agreement with the experimental results. Numerical results show that the static pressure on pressure side of rotor blades increases slightly at radial direction, and remains almost constant in circumferential direction at design conditions, while it increases gradually from inlet to exit on suction side along the flow direction. The static pressure, total pressure and velocity at inlet, rotor blade exit and stator outlet were measured by five-hole probe. The experimental results show, inlet flow is almost axial and the prerotation is very small at design conditions. The meridional velocity and circulation distributions are almost uniform at rotor blades exit at design condition. The residual circulation still exists at downstream of stator, and the absolute flow angle at radial direction is almost consistent at design conditions, but Cu increases linearly from hub to tip at small flow rate conditions. To determine the influence of the hub leakage, a contrast experiment was accomplished. The measurement results show that hub leakage results in the decrease of efficiency, and the meridional velocity and circulation at rotor blade exit, especially near hub leakage region are influenced by the leakage.

scholarly journals Investigation of Rotor Blade Roughness Effects on Turbine Performance

1993 ◽  
Vol 115 (3) ◽  
pp. 614-620 ◽  
Author(s):  
J. L. Boynton ◽  
R. Tabibzadeh ◽  
S. T. Hudson
Keyword(s):  
Surface Finish ◽  
Space Shuttle ◽  
Power Level ◽  
Rotor Blades ◽  
Machining Process ◽  
Inlet Temperature ◽  
Test Results ◽  
Roughness Effects ◽  
Turbine Efficiency ◽  
Swirl Angle

The cold air test program was completed on the SSME (Space Shuttle Main Engine) HPFTP (High-Pressure Fuel Turbopump) turbine with production nozzle vane rings and polished coated rotor blades with a smooth surface finish of 30 μin. (0.76 μm) rms (root mean square). The smooth blades were polished by an abrasive flow machining process. The test results were compared with the air test results from production rough-coated rotor blades with a surface finish of up to 400 μin. (10.16 μm) rms. Turbine efficiency was higher for the smooth blades over the entire range tested. Efficiency increased 2.1 percentage points at the SSME 104 percent RPL (Rated Power Level) conditions. This efficiency improvement could reduce the SSME HPFTP turbine inlet temperature by 57 R (32 K), increasing turbine durability. The turbine flow parameter increased and the midspan outlet swirl angle became more axial with the smooth rotor blades.

Aerodynamic Performance of an Axial Compressor Stage With Variable Rotor Blades and Variable Inlet Guide Vanes

1998 ◽  
Author(s):  
Václav Cyrus
Keyword(s):  
Volume Flow Rate ◽  
Pressure Coefficient ◽  
Axial Flow ◽  
Aerodynamic Performance ◽  
Rotating Stall ◽  
Rotor Blades ◽  
Flow Coefficient ◽  
Experimental Investigations ◽  
Compressor Stage ◽  
Flow Stage

Experimental investigations of flow fields and losses in an axial flow compressor stage were carried out. The stage has hub/tip ratio of 0.7. The design values of flow coefficient and pressure coefficient are 0.6 and 0.81, respectively. Aerodynamic performance was investigated for two principal configurations: i) axial flow stage with variable rotor blades, ii) axial flow stage with variable inlet guide and stator vanes. The most efficient volume flow rate regulation of the stage was with the application of variable rotor blades. On the basis of experimental data an analysis of the origin of flow separation on the suction and pressure surfaces of rotor and stator blades was made with the use of simple design criteria. The unsteady flow of rotating stall type in the tested stage appeared after simultaneous occurence of large stall regions in both rotor and stator blade rows. The existence of large stall regions in the IGV did not affect the rotating stall onset. At high values of the IGV stagger angle change (50 deg) pressure pulsations appeared due to the occurence of stall.

Sign in / Sign up

Export Citation Format

Share Document