scholarly journals Unsteady Pressure Measurements in a Rotating Centrifugal Impeller

1992 ◽  
Author(s):  
G. Roth
Keyword(s):  
Surface Pressure ◽  
Suction Side ◽  
Rotating Stall ◽  
Centrifugal Impeller ◽  
Pressure Measurements ◽  
Blade Surface ◽  
Pressure Transducers ◽  
Engine Order ◽  
Analysis Technique ◽  
Stable Operating

The design of a shrouded radial test impeller which enables the application of miniature pressure transducers inside the blades is presented. An explanation of the measurement and analysis technique is given. The results of suction side blade surface pressure measurements at several points of a performance line are presented. Two different types of diffuser rotating stall were detected. The pressure behaviour at impeller stall and surge inception is demonstrated. Furthermore, the periodic engine order blade surface pressure signals at a stable operating point are shown.

Three Dimensional Unsteady Pressure Measurements for an Oscillating Turbine Blade

1997 ◽  
Author(s):  
D. L. Bell ◽  
L. He
Keyword(s):  
Turbine Blade ◽  
Surface Pressure ◽  
Three Dimensional ◽  
Test Facility ◽  
Pressure Measurements ◽  
Blade Surface ◽  
Low Speed ◽  
Pressure Transducers ◽  
Bending Mode ◽  
Oscillation Frequencies

A complete set of unsteady blade surface pressure measurements is presented for a single turbine blade oscillating in a three dimensional bending mode. Results are provided for five spanwise sections at 10%, 30%, 50%, 70% and 90% of span. Steady blade pressure measurements and five-hole probe traverses at the inlet and exit planes of the test section, are also included. The test facility operates at low speed and the working section consists of a single turbine blade mounted in a profiled duct. A rigid blade with constant section was used, and a three dimensional bending mode realised by hinging the blade at root and driving the tip section. The low speed and scale of the test facility allowed low oscillation frequencies (5 to 20 Hz) to be employed, in order to match realistic reduced frequencies. This enabled the unsteady blade surface pressure response to be recorded with externally mounted pressure transducers. The validity of this technique is examined. Results from the test facility demonstrate a noticeable three dimensional behaviour of the unsteady flow.

scholarly journals Effects of Transducer Installation on Unsteady Pressure Measurements on Oscillating Blades

2005 ◽  
Author(s):  
J. Lepicovsky
Keyword(s):  
Suction Side ◽  
Forced Oscillations ◽  
Pressure Measurements ◽  
Signal Distortion ◽  
Blade Surface ◽  
Pressure Transducers ◽  
Unsteady Pressure ◽  
Custom Made ◽  
Oscillation Frequencies ◽  
Unsteady Pressure Measurements

Unsteady pressures were measured above the suction side of a blade that was oscillated to simulate blade stall flutter. Measurements were made at blade oscillation frequencies up to 500 Hz. Two types of miniature pressure transducers were used: surface-mounted flat custom-made, and commercial miniature, body-mounted transducers. The signals of the surface-mounted transducers are significantly affected by blade acceleration, whereas the signals of body-mounted transducers are practically free of this distortion. A procedure was introduced to correct the signals of surface-mounted transducers to rectify the signal distortion due to blade acceleration. The signals from body-mounted transducers, and corrected signals from surface-mounted transducers represent true unsteady pressure signals on the surface of a blade subjected to forced oscillations. However, the use of body-mounted commercial transducers is preferred for the following reasons: no signal corrections are needed for blade acceleration, the conventional transducers are noticeably less expensive than custom-made flat transducers, the survival rate of body-mounted transducers is much higher, and finally installation of body-mounted transducers does not disturb the blade surface of interest.

scholarly journals Detailed Pressure Measurements During the Transition to Rotating Stall in an Axial Compressor: Influence of the Throttling Process

2018 ◽  
Author(s):  
Gabriel Margalida ◽  
Antoine Dazin ◽  
Pierric Joseph ◽  
Olivier Roussette
Keyword(s):  
Axial Compressor ◽  
Warning Signal ◽  
Rotating Stall ◽  
Pressure Measurements ◽  
Pressure Signal ◽  
Instability Development ◽  
Stable Operating ◽  
Instantaneous Pressure ◽  
Reference Pressure ◽  
Unsteady Pressure Measurements

This paper presents experimental unsteady pressure measurements gathered on a single stage axial compressor during pre-stall and transition to stall operations. The aim of this study is to analyze the transition from a stable operating point to the fully developed rotating stall regime, and more specifically, the effect of the throttling process on the development of the instabilities. To do so, experiments have been repeated leading the compressor to stall operations with various throttling speed. On one hand, this paper analyses the effect of the throttling speed on the dynamic of the instability development from the first detection of spike type precursors to completely developed rotating stall. On the other hand, a stall warning signal based on the correlation of the instantaneous pressure signal with a reference pressure signal is built. The influence of the location of the pressure transducer used for the warning signal is first analyzed. Then an analysis of the effect of the throttling process on the time between the warning signal and the effective stall development is proposed.

Time-Averaged Heat Transfer and Pressure Measurements and Comparison With Prediction for a Two-Stage Turbine

1994 ◽  
Vol 116 (1) ◽  
pp. 14-22 ◽  
Author(s):  
M. G. Dunn ◽  
J. Kim ◽  
K. C. Civinskas ◽  
R. J. Boyle
Keyword(s):  
Surface Pressure ◽  
Space Shuttle ◽  
Three Dimensional ◽  
Stanton Number ◽  
Navier Stokes ◽  
Pressure Measurements ◽  
Two Stage ◽  
Pressure Transducers ◽  
Pressure Distributions ◽  
Main Engine

Time-averaged Stanton number and surface-pressure distributions are reported for the first-stage vane row and the first-stage blade row of the Rocketdyne Space Shuttle Main Engine two-stage fuel-side turbine. These measurements were made at 10, 50, and 90 percent span on both the pressure and suction surfaces of the component. Stanton-number distributions are also reported for the second-stage vane at 50 percent span. A shock tube is used as a short-duration source of heated and pressurized air to which the turbine is subjected. Platinum thin-film gages are used to obtain the heat-flux measurements and miniature silicone-diaphragm pressure transducers are used to obtain the surface pressure measurements. The first-stage vane Stanton number distributions are compared with predictions obtained using a quasi-three dimensional Navier–Stokes solution and a version of STAN5. This same N–S technique was also used to obtain predictions for the first blade and the second vane.

scholarly journals An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

2000 ◽  
Vol 123 (2) ◽  
pp. 418-428 ◽  
Author(s):  
Mark P. Wernet ◽  
Michelle M. Bright ◽  
Gary J. Skoch
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Transient Flow ◽  
Dynamic Pressure ◽  
Rotating Stall ◽  
Transient Pressure ◽  
Pressure Transducers ◽  
Stable Operating ◽  
Particle Imaging

Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in high-speed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

System to Measure the Pressure Distribution on Fan Aerofoil Surfaces During Flutter Conditions

1980 ◽  
Vol 102 (4) ◽  
pp. 427-432
Author(s):  
John W. H. Chivers
Keyword(s):  
Surface Pressure ◽  
High Speed ◽  
Cross Correlation ◽  
Test Results ◽  
Blade Surface ◽  
Pressure Data ◽  
Pressure Transducers ◽  
Induced Stress ◽  
Blade Tip ◽  
Typical Test

In order to assist in the understanding of high speed flutter, a series of tests has been conducted on a research fan in which the blade surface pressures have been measured by means of miniature silicon diaphragm pressure transducers embedded in selected fan blades. Prior to this investigation a program of rig tests was conducted to examine the effects of centrifugal force and vibration on the transducer performance and a transducer mounting technique was developed to minimize blade induced stress in the transducer. Instantaneous measurements of the tip stagger angles of the pressure instrumented fan blades have enabled a cross correlation to be performed on the blade surface pressure data and the blade tip angles. Some typical test results are shown.

Time-Averaged Heat Transfer and Pressure Measurements and Comparison With Prediction for a Two-Stage Turbine

1992 ◽  
Author(s):  
M. G. Dunn ◽  
J. Kim ◽  
K. C. Civinskas ◽  
R. J. Boyle
Keyword(s):  
Surface Pressure ◽  
Space Shuttle ◽  
Stanton Number ◽  
Navier Stokes ◽  
Pressure Measurements ◽  
Two Stage ◽  
Pressure Transducers ◽  
Pressure Distributions ◽  
Flux Measurements ◽  
Main Engine

Time-averaged Stanton number and surface-pressure distributions are reported for the first-stage vane row and the first-stage blade row of the Rocketdyne Space Shuttle Main Engine two-stage fuel-side turbine. These measurements were made at 10%, 50%, and 90% span on both the pressure and suction surfaces of the component. Stanton-number distributions are also reported for the second-stage vane at 50% span. A shock tube is used as a short-duration source of heated and pressurized air to which the turbine is subjected. Platinum thin-film pages are used to obtain the heat-flux measurements and miniature silicone-diaphragm pressure transducers are used to obtain the surface pressure measurements. The first-stage vane Stanton number distributions are compared with predictions obtained using a quasi-3D Navier-Stokes solution and a version of STAN5. This same N-S technique was also used to obtain predictions for the first blade and the second vane.

Blade Surface Pressure Measurements on a Low Pressure Rise Axial Flow Fan

2020 ◽  
Author(s):  
Johannes Rohwer ◽  
Sybrand J. van der Spuy ◽  
Theodor W. von Backström ◽  
Francois G. Louw
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Surface Pressure ◽  
Static Pressure ◽  
Axial Flow ◽  
Pressure Rise ◽  
Test Facility ◽  
Pressure Measurements ◽  
Blade Surface ◽  
Axial Flow Fan

Abstract Fan performance characteristic tests of axial flow fans provide information on the global flow field, based on stable inlet flow field distribution. More information is often required on the local flow distribution existing in the vicinity of the fan blades under installed conditions. A 1.542 m diameter scale model of an axial flow fan, termed the M-Fan is tested in an ISO 5801, type A, test facility. The M-fan was specifically designed for low-pressure, high flow rate application in air-cooled or hybrid condensers. The scaled version of the M-fan was designed to have a fan static pressure rise of 116.7 Pa at a flow rate of 14.2 m3/s. Two specially constructed M-Fan blades are manufactured to conduct blade surface pressure measurements on the blades. The fan blades are equipped with 2 mm diameter tubes that run down the length of the fan blades in order to convey the measured pressure. Piezo-resistive pressure transducers, located on the hub of the fan, measure the static pressure distribution on the blades and the data is transferred to a stationary computer using a wireless telemetry setup. The blade pressure measurement setup is re-commissioned from a previous research project and its performance is qualified by testing and comparing to experimental results obtained on the B2a-fan. Excellent correlation to previous results is obtained. The experimental M-fan results are compared against results from a periodic numerical CFD model of a fan blade modelled in an ISO 5801, Type A test facility configuration. The experimental tests and numerical model correlate well with each other. The experimental blade surface pressure measurements have a minimum Pearson correlation to the numerically determined values of 0.932 (maximum 0.971).

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