Time-Resolved Flow Field Measurements of Momentum Driven Pulsed, Transient Jets

2017 ◽  
Author(s):  
Zheng Zhang ◽  
Dhuree Seth ◽  
Sravan Kumar Artham ◽  
John G. Leishman ◽  
Ebenezer P. Gnanamanickam
Keyword(s):  
Flow Field ◽  
Field Measurements ◽  
Time Resolved

Evaluating the Influence of Rotor-Casing Eccentricity on Turbine Efficiency Including Time-Resolved Flow Field Measurements

2021 ◽  
pp. 1-33
Author(s):  
Eric DeShong ◽  
Shawn Siroka ◽  
Reid A. Berdanier ◽  
Karen A. Thole
Keyword(s):  
Flow Field ◽  
Magnetic Levitation ◽  
Field Measurements ◽  
Tip Clearance ◽  
Time Resolved ◽  
Flow Angle ◽  
Turbine Efficiency ◽  
Eccentric Rotor ◽  
Blade Tip ◽  
Manufacturing Techniques

Abstract The clearance that exists between the casing and turbine blade tips is one of the key drivers of efficiency in gas turbine engines. For this reason, engine manufacturers utilize precise manufacturing techniques and may employ clearance control systems to minimize tip clearances to reduce associated losses. Despite these efforts, turbines typically exhibit some nominal casing ovality or rotor-casing eccentricity, and changes to blade tip clearance during operation commonly occur due to thermal and mechanical stresses. The present study investigates non-axisymmetric tip clearance effects by creating a rotor-casing eccentricity in a one-stage axial test turbine operating in a continuous-duration mode at engine relevant conditions with engine representative hardware. A magnetic levitation bearing system was leveraged to move the turbine shaft to vary the rotor-casing eccentricity without test section disassembly. The results of this study indicate that rotor-casing eccentricity does not affect overall turbine efficiency over the range that was tested, but does locally influence efficiency and the rotor exit flow field. Comparisons of flow angle and secondary flow kinetic energy agreed with previous studies and existing analytical methods, respectively. Collectively, these results indicate that tip clearance can be studied locally on an eccentric rotor.

Time resolved flow-field measurements of a turbulent mixing layer over a rectangular cavity

2010 ◽  
Vol 51 (1) ◽  
pp. 51-63 ◽  
Author(s):  
Shiyao Bian ◽  
James F. Driscoll ◽  
Brian R. Elbing ◽  
Steven L. Ceccio
Keyword(s):  
Flow Field ◽  
Turbulent Mixing ◽  
Mixing Layer ◽  
Field Measurements ◽  
Rectangular Cavity ◽  
Time Resolved ◽  
Turbulent Mixing Layer

Vortex-Wake-Blade Interaction in a Shrouded Axial Turbine

2004 ◽  
Author(s):  
J. Schlienger ◽  
A. I. Kalfas ◽  
R. S. Abhari
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Interaction Mechanism ◽  
Leading Edge ◽  
Field Measurements ◽  
Second Phase ◽  
Time Resolved ◽  
Axial Turbine ◽  
High Loss ◽  
High Level

This paper presents the results of time-resolved flow field measurements of a multistage shrouded axial turbine. The unsteady interaction mechanism between the rotor’s secondary flow vortices, the rotor’s wake and the adjacent blading at the exit plane of the first turbine stage is of prime interest and analysed in detail. Three key phases are identified for one blade passing event. The first phase shows a quasi undisturbed convection of the rotor’s secondary flow field into the downstream stator. The second phase shows a migration of high loss fluid from the wake layer into the passage and horse-shoe vortices at the rotor hub section. The relative motion between the rotor and stator blades brings the two vortices closer to the wake layer and lets the flow features interact with each other. The third phase focuses on the rotor indigenous hub vortices that are bent and stretched around the stator’s leading edge. The signal analysis of the time-resolved flow field indicates a high level of unsteadiness at the stator’s pressure side. The associated unsteadiness within the flow field is evaluated and quantified on the basis of pitchwise averaged space-time diagrams. The obtained results are finally discussed and explained using two flow schematics within and at the end of the paper.

Time-resolved mixing and flow-field measurements during droplet formation in a flow-focusing junction

2015 ◽  
Vol 25 (8) ◽  
pp. 084014 ◽  
Author(s):  
Odile Carrier ◽  
F Gökhan Ergin ◽  
Huai-Zhi Li ◽  
Bo B Watz ◽  
Denis Funfschilling
Keyword(s):  
Flow Field ◽  
Field Measurements ◽  
Droplet Formation ◽  
Flow Focusing ◽  
Time Resolved

Evaluating the Influence of Rotor-Casing Eccentricity on Turbine Efficiency Including Time-Resolved Flow Field Measurements

2021 ◽  
Author(s):  
Eric T. DeShong ◽  
Shawn Siroka ◽  
Reid A. Berdanier ◽  
Karen A. Thole
Keyword(s):  
Flow Field ◽  
Magnetic Levitation ◽  
Field Measurements ◽  
Tip Clearance ◽  
Time Resolved ◽  
Flow Angle ◽  
Turbine Efficiency ◽  
Eccentric Rotor ◽  
Blade Tip ◽  
Manufacturing Techniques

Abstract The clearance that exists between the casing and turbine blade tips is one of the key drivers of efficiency in gas turbine engines. For this reason, engine manufacturers utilize precise manufacturing techniques and may employ clearance control systems to minimize tip clearances to reduce associated losses. Despite these efforts, turbines typically exhibit some nominal casing ovality or rotor-casing eccentricity, and changes to blade tip clearance during operation commonly occur due to thermal and mechanical stresses. The present study investigates non-axisymmetric tip clearance effects by creating a rotor-casing eccentricity in a one-stage axial test turbine operating in a continuous-duration mode at engine relevant conditions with engine representative hardware. A magnetic levitation bearing system was leveraged to move the turbine shaft to vary the rotor-casing eccentricity without test section disassembly. The results of this study indicate that rotor-casing eccentricity does not affect overall turbine efficiency over the range that was tested, but does locally influence efficiency and the rotor exit flow field. Comparisons of flow angle and secondary flow kinetic energy agreed with previous studies and existing analytical methods, respectively. Collectively, these results indicate that tip clearance can be studied locally on an eccentric rotor.

Time resolved flow field measurements of orifice entrainment during a hydrodynamic ram event

2016 ◽  
Vol 20 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Andrew J. Lingenfelter ◽  
David Liu ◽  
Mark F. Reeder
Keyword(s):  
Flow Field ◽  
Field Measurements ◽  
Time Resolved ◽  
Hydrodynamic Ram

Influence of Mach Number and Aerodynamic Loading on Rotating Instability in an Annular Compressor Cascade

2012 ◽  
Author(s):  
Christian Beselt ◽  
Dieter Peitsch
Keyword(s):  
Mach Number ◽  
Flow Field ◽  
Steady Flow ◽  
Field Measurements ◽  
Sudden Increase ◽  
Compressor Cascade ◽  
Time Resolved ◽  
Aerodynamic Loading ◽  
Rotating Instability ◽  
Time Resolved Measurements

An experimental study was conducted to investigate the influence of Mach number and aerodynamic loading on Rotating Instability (RI). Investigations were performed on an annular compressor cascade with radial clearance at the hub. In addition to steady flow field measurements, time resolved measurements of static wall-pressure at the hub, close to the tip clearance, were performed. For a specific range of incidence angles, RI could be detected at all flow speeds (Ma = 0.2–0.7). Shortly before the inception of RI, a sudden increase in pressure loss coefficient and outflow angle was detected by steady flow field measurements. The time resolved measurements showed an abruptly broadband increase of amplitude in the frequency range, in which RI occurs at higher loadings. RI propagates with 25–33% of the circumferential component of the upstream flow speed. Furthermore it is possible to scale the power spectral density function of the unsteady data with Strouhal number.

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