scholarly journals Inlet Distortion Generated Periodic Aerodynamic Rotor Response

1989 ◽  
Author(s):  
Steven R. Manwaring ◽  
Sanford Fleeter
Keyword(s):  
Rotor Blade ◽  
Amplitude Ratio ◽  
Unsteady Aerodynamics ◽  
Mean Flow ◽  
Suction Surface ◽  
Unsteady Pressure ◽  
Pressure Surface ◽  
Inlet Distortion ◽  
Loading Level ◽  
Forcing Function

Fundamental inlet distortion generated rotor blade row unsteady aerodynamics, including the effects of both the detailed aerodynamic forcing function for the first time and steady loading are experimentally investigated in an extensively instrumented axial flow research compressor. A two-per-rev forcing function with three gust amplitude ratios is generated. On the rotor blade pressure surface, the unsteady pressure nondimensionalization compresses the magnitude data with mean flow incidence angle. This is not the case on the higher camber suction surface. Also, these pressure surface unsteady data are primarily affected by the steady loading level whereas the suction surface unsteady data are a function of the steady loading level and distribution as well as the gust amplitude ratio. In addition, a design inlet distortion blade surface unsteady pressure correlation is considered.

Inlet Distortion Generated Periodic Aerodynamic Rotor Response

1990 ◽  
Vol 112 (2) ◽  
pp. 298-307 ◽  
Author(s):  
S. R. Manwaring ◽  
S. Fleeter
Keyword(s):  
Rotor Blade ◽  
Amplitude Ratio ◽  
Unsteady Aerodynamics ◽  
Mean Flow ◽  
Suction Surface ◽  
Unsteady Pressure ◽  
Pressure Surface ◽  
Inlet Distortion ◽  
Loading Level ◽  
Forcing Function

Fundamental inlet distortion-generated rotor blade row unsteady aerodynamics, including the effects of both the detailed aerodynamic forcing function for the first time and steady loading are experimentally investigated in an extensively instrumented axial-flow research compressor. A two-per-rev forcing function with three gust amplitude ratios is generated. On the rotor blade pressure surface, the unsteady pressure nondimensionalization compresses the magnitude data with mean flow incidence angle. This is not the case on the higher camber suction surface. These pressure surface unsteady data are primarily affected by the steady loading level, whereas the suction surface unsteady data are a function of the steady loading level and distribution as well as the gust amplitude ratio. In addition, a design inlet distortion blade surface unsteady pressure correlation is considered.

Blade Forcing Function and Aerodynamic Work Measurements in a High Speed Centrifugal Compressor With Inlet Distortion

2009 ◽  
Author(s):  
Albert Kammerer ◽  
Reza S. Abhari
Keyword(s):  
Failure Modes ◽  
Pressure Sensors ◽  
Forced Response ◽  
Blade Surface ◽  
Centrifugal Compressors ◽  
Flow Distortion ◽  
Unsteady Pressure ◽  
Inlet Distortion ◽  
Forcing Function ◽  
Work Distribution

Centrifugal compressors operating at varying rotational speeds, such as in helicopters or turbochargers, can experience forced response failure modes. The response of the compressors can be triggered by aerodynamic flow non-uniformities, such as with diffuser-impeller interaction or with inlet distortions. The work presented here addresses experimental investigations of forced response in centrifugal compressors with inlet distortions. This research is part of an ongoing effort to develop related experimental techniques and to provide data for validation of computational tools. In this work measurements of blade surface pressure and aerodynamic work distribution were addressed. A series of pressure sensors were designed and installed on rotating impeller blades and simultaneous measurements with blade-mounted strain gauges were performed under engine representative conditions. To the best knowledge of the authors, this is the first publication which presents comprehensive experimental unsteady pressure measurements during forced response for highspeed radial compressors. Experimental data were obtained for both resonance and off-resonance conditions with uniquely tailored inlet distortion. This paper covers aspects relating to the design of fast response pressure sensors and their installation on thin impeller blades. Additionally, sensor properties are outlined with a focus on calibration and measurement uncertainty estimations. The second part of this paper presents unsteady pressure results taken for a number of inlet distortion cases. It will be shown that the intended excitation order due to inlet flow distortion is of comparable magnitude to the second and third harmonics which are consistently observed in all measurements. Finally, an experimental method will be outlined that enables the measurement aerodynamic work on the blade surface during resonant crossing. This approach quantifies the energy exchange between the blade and the flow in terms of cyclic work along the blade surface. The phase angle between the unsteady pressure and the blade movement will be shown to determine the direction of energy transfer between the blade and the fluid.

Blade Forcing Function and Aerodynamic Work Measurements in a High Speed Centrifugal Compressor With Inlet Distortion

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Albert Kammerer ◽  
Reza S. Abhari
Keyword(s):  
High Speed ◽  
Pressure Sensors ◽  
Forced Response ◽  
Blade Surface ◽  
Centrifugal Compressors ◽  
Flow Distortion ◽  
Unsteady Pressure ◽  
Inlet Distortion ◽  
Forcing Function ◽  
Work Distribution

Centrifugal compressors operating at varying rotational speeds, such as in helicopters or turbochargers, can experience forced response failure modes. The response of the compressors can be triggered by aerodynamic flow nonuniformities such as with diffuser-impeller interaction or with inlet distortions. The work presented here addresses experimental investigations of forced response in centrifugal compressors with inlet distortions. This research is part of an ongoing effort to develop related experimental techniques and to provide data for validation of computational tools. In this work, measurements of blade surface pressure and aerodynamic work distribution were addressed. A series of pressure sensors were designed and installed on rotating impeller blades and simultaneous measurements with blade-mounted strain gauges were performed under engine representative conditions. To the best knowledge of the authors, this is the first publication, which presents comprehensive experimental unsteady pressure measurements during forced response, for high-speed radial compressors. The experimental data were obtained for both resonance and off-resonance conditions with uniquely tailored inlet distortion. This paper covers aspects relating to the design of fast response pressure sensors and their installation on thin impeller blades. Additionally, sensor properties are outlined with a focus on calibration and measurement uncertainty estimations. The second part of this paper presents unsteady pressure results taken for a number of inlet distortion cases. It will be shown that the intended excitation order due to inlet flow distortion is of comparable magnitude to the second and third harmonics, which are consistently observed in all measurements. Finally, an experimental method will be outlined that enables the measurement of aerodynamic work on the blade surface during resonant crossing. This approach quantifies the energy exchange between the blade and the flow in terms of cyclic work along the blade surface. The phase angle between the unsteady pressure and the blade movement will be shown to determine the direction of energy transfer.

Unsteady Flow in Oscillating Turbine Cascade: Part 1 — Linear Cascade Experiment

1996 ◽  
Author(s):  
L. He
Keyword(s):  
Computational Study ◽  
Separation Bubble ◽  
Turbine Blades ◽  
Leading Edge ◽  
Computational Method ◽  
Reattachment Point ◽  
Suction Surface ◽  
Linear Cascade ◽  
Unsteady Pressure ◽  
Pressure Surface

An experimental and computational study has been carried out on a linear cascade of low pressure turbine blades with the middle blade oscillating in a torsion mode. The main objectives of the present work were to enhance understanding of the behaviour of bubble type of flow separation and to examine the predictive ability of a computational method. In addition, an attempt was made to address a general modelling issue: was the linear assumption adequately valid for such kind of flow? In Part 1 of this paper, the experimental work was described. Unsteady pressure was measured along blade surfaces using off-board mounted pressure transducers at realistic reduced frequency conditions. A short separation bubble on the suction surface near the trailing edge and a long leading-edge separation bubble on the pressure surface were identified. It was found that in the regions of separation bubbles, unsteady pressure was largely influenced by the movement of reattachment point, featured by an abrupt phase shift and an amplitude trough in the 1st harmonic distribution. The short bubble on the suction surface seemed to follow closely a laminar bubble transition model in a quasi-steady manner, and had a localized effect. The leading-edge long bubble on the pressure surface, on the other hand, was featured by a large movement of the reattachment point, which affected the surface unsteady pressure distribution substantially. As far as the aerodynamic damping was concerned, there was a destabilizing effect in the separated flow region, which was however largely balanced by the stabilizing effect downstream of the reattachment point due to the abrupt phase change.

scholarly journals Film Cooling on a Gas Turbine Rotor Blade

1991 ◽  
Author(s):  
Kenichiro Takeishi ◽  
Sunao Aoki ◽  
Tomohiko Sato ◽  
Keizo Tsukagoshi
Keyword(s):  
Mass Transfer ◽  
Film Cooling ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Suction Surface ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Turbine Rotor Blade ◽  
Pressure Surface ◽  
Rotating Blade

The film cooling effectiveness on a low-speed stationary cascade and the rotating blade has been measured by using a heat-mass transfer analogy. The film cooling effectiveness on the suction surface of the rotating blade fits well with that on the stationary blade, but a low level of effectiveness appears on the pressure surface of the rotating blade. In this paper, typical film cooling data will be presented and film cooling on a rotating blade is discussed.

scholarly journals Unsteady Flow in a Single Stage Turbine

1998 ◽  
Author(s):  
Mary A. Hilditch ◽  
Graham C. Smith ◽  
Udai K. Singh
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Pressure Fluctuations ◽  
Pressure Waves ◽  
Turbine Stage ◽  
Unsteady Heat Transfer ◽  
High Pressure Turbine ◽  
Suction Surface ◽  
Pressure Surface ◽  
Wake Interaction

This paper presents unsteady pressure and heat transfer measurements made on a high pressure turbine stage at DERA Pyestock, and compares them with numerical simulations made using the 2D unsteady code UNSFLO. The aim of the work was to evaluate the performance of the code, and to use the predictions to allow a fuller interpretation of the flow physics than could have been achieved from the measurements alone. The unsteady heat transfer and pressure fluctuations around the mid height section of the rotor blade have been examined in detail. Agreement between measured and predicted pressure fluctuations on the rotor was excellent. Interaction with the ngv potential field dominated the pressure surface, while the suction surface showed pressure waves moving forward over the blade, possibly as a result of shock/wake interaction.

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.

Heat Transfer to a Pvd Rotor Blade at High Subsonic Passage Throat Mach Numbers

1978 ◽  
Vol 192 (1) ◽  
pp. 225-235 ◽  
Author(s):  
B. W. Martin ◽  
A. Brown ◽  
S. E. Garrett
Keyword(s):  
Heat Transfer ◽  
Rotor Blade ◽  
Local Heat Transfer ◽  
Reynolds Numbers ◽  
Local Heat ◽  
Transfer Coefficients ◽  
Suction Surface ◽  
Pressure Surface ◽  
Air Stream ◽  
Mach Numbers

This paper reports heat-transfer measurements round a PVD rotor blade using a transient method. Instrumented syndanio-asbestos blades forming part of a cascade are suddenly introduced into a heated air stream, the temperature-time response of surface thermocouples attached to copper inserts in the blades then being used to determine local heat-transfer coefficients for (a) passage throat Mach numbers between 0.79 and 0.94 (b) turbulence intensities from 4.15 to 9.05 per cent (c) blade chord Reynolds numbers from 7.8 times 105 to 8.9 times 105. Measured transition lengths on the suction surface, over which the heat transfer nearly trebles, are somewhat short in relation to other measurements. The onset of transition, which is downstream of predictions for the higher Reynolds numbers but accords with the trends of existing correlations, is little influenced by turbulence intensity variations in the above range. Over the pressure surface the heat transfer is less than for a fully-turbulent boundary layer. Comparisons with other high Mach-number measurements suggest that much further work is needed before the effects of scale of turbulence are fully understood.

Forcing Function Effects on Rotor Periodic Aerodynamic Response

1991 ◽  
Vol 113 (2) ◽  
pp. 312-319 ◽  
Author(s):  
S. R. Manwaring ◽  
S. Fleeter
Keyword(s):  
Axial Flow ◽  
Unsteady Aerodynamics ◽  
Harmonic Response ◽  
Inlet Distortion ◽  
Forcing Function ◽  
Reduced Frequency ◽  
Blade Row ◽  
Forcing Functions ◽  
Series Of Experiments ◽  
The Difference

A series of experiments are performed in an extensively instrumented axial flow research compressor to investigate the effects of different low reduced frequency aerodynamic forcing functions and steady loading level on the gust-generated unsteady aerodynamics of a first-stage rotor blade row. Two different two-per-rev forcing functions are considered: (1) the velocity deficit from two 90 deg circumferential inlet flow distortions, and (2) the wakes from two upstream obstructions, which are characteristic of airfoil or probe excitations. The data show that the wake-generated rotor row first harmonic response is much greater than that generated by the inlet distortion, with the difference decreasing with increased steady loading.

Film Cooling on a Gas Turbine Rotor Blade

1992 ◽  
Vol 114 (4) ◽  
pp. 828-834 ◽  
Author(s):  
K. Takeishi ◽  
S. Aoki ◽  
T. Sato ◽  
K. Tsukagoshi
Keyword(s):  
Mass Transfer ◽  
Film Cooling ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Suction Surface ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Turbine Rotor Blade ◽  
Pressure Surface ◽  
Rotating Blade

The film cooling effectiveness on a low-speed stationary cascade and the rotating blade has been measured by using a heat-mass transfer analogy. The film cooling effectiveness on the suction surface of the rotating blade fits well with that on the stationary blade, but a low level of effectiveness appears on the pressure surface of the rotating blade. In this paper, typical film cooling data will be presented and film cooling on a rotating blade is discussed.

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