scholarly journals Fan Noise Source Diagnostic Test - Computation of Rotor Wake Turbulence Noise

2002 ◽  
Author(s):  
M Nallasamy ◽  
Edmane Envia ◽  
Scott Thorp ◽  
Aamir Shabbir
Keyword(s):  
Diagnostic Test ◽  
Noise Source ◽  
Fan Noise ◽  
Rotor Wake ◽  
Wake Turbulence ◽  
Test Computation

Fan Noise Source Diagnostic Test -- Far-field Acoustic Results

2002 ◽  
Author(s):  
Richard Woodward ◽  
Christopher Hughes ◽  
Robert Jeracki ◽  
Christopher Miller
Keyword(s):  
Diagnostic Test ◽  
Noise Source ◽  
Far Field ◽  
Fan Noise

scholarly journals Blade Row Interaction in a Multistage Low-Pressure Turbine

1991 ◽  
Author(s):  
N. Arndt
Keyword(s):  
Rotor Blade ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Secondary Flows ◽  
Rotor Wake ◽  
Low Pressure Turbine ◽  
Wake Turbulence ◽  
Blade Row ◽  
Flow Phenomena ◽  
Flow Through

The objective of this work was to enhance the understanding of unsteady flow phenomena in multistage low-pressure turbines. For this purpose, hot-film probe measurements were made downstream of every rotor blade row of a five-stage low-pressure turbine. Rotor-rotor interaction and stator-rotor interaction were observed to have a profound influence on the flow through the low-pressure turbine. Interaction of rotors of different turbine stages occurred owing to the influence of the wakes shed by one rotor blade row upon the flow through the next downstream rotor blade row. This wake-induced rotor-rotor interaction resulted in strongly amplitude-modulated periodic and turbulent velocity fluctuations downstream of every rotor blade row with the exception of the most upstream one. Significantly different wake depths and turbulence levels measured downstream of every rotor blade row at different circumferential positions evidenced the effect of the circumferentially nonuniform stator exit flow upon the next downstream rotor blade row. Stator-rotor interaction also strongly influenced the overturning and the underturning of the rotor wakes, caused by the rotor secondary flows, in the rotor endwall regions. Low rotor wake overturning and underturning, i.e., reduced rotor secondary flow influence, were observed to correlate well with low rotor wake turbulence levels.

Effect of Rotor Tip Speed and Stator Sweep on Rotor-Stator Interaction

2004 ◽  
Author(s):  
Oliver V. Atassi ◽  
Christopher M. Hall
Keyword(s):  
Diagnostic Test ◽  
Correlation Length ◽  
Radial Distribution ◽  
Noise Source ◽  
Guide Vane ◽  
Phase Variation ◽  
Periodic Component ◽  
Source Regions ◽  
Rotor Stator Interaction ◽  
Radial Phase

Data taken in the Source Diagnostic Test of the unsteady pressure on a fan-exit guide vane is analyzed to identify the dominant noise producing regions on the vane. The dominant noise source regions of the vane are identified as the outer fifty percent span of the vane. The sensitivity of this result to fan tip speed and exit guide vane sweep is studied. Sweep is seen to decrease the radial correlation length of the unsteady vane response and hence decrease the noise produced by wake-vane interaction. Results for the periodic component of the fan wakes show that the magnitude of the wake harmonics is largest in the outer fifty percent span of the duct and the radial phase variation is largest in the hub region. These results demonstrate a strong cause and effect relationship between the radial distribution of the wake harmonics and the dominant noise producing regions on the fan-exit guide vane.

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