scholarly journals Dynamic-stall measurements using time-resolved pressure-sensitive paint on double-swept rotor blades

2021 ◽  
Vol 63 (1) ◽  
Author(s):  
Armin Weiss ◽  
Reinhard Geisler ◽  
Martin M. Müller ◽  
Christian Klein ◽  
Ulrich Henne ◽  
...  
Keyword(s):  
Measurement System ◽  
Transient Flow ◽  
Fast Response ◽  
Rotor Blades ◽  
Dynamic Stall ◽  
Test Facility ◽  
Pressure Sensitive Paint ◽  
Detached Eddy Simulation ◽  
Pressure Transducers ◽  
Pressure Sensitive

Abstract The study presents an optimized pressure-sensitive paint (PSP) measurement system that was applied to investigate unsteady surface pressures on recently developed double-swept rotor blades in the rotor test facility at the German Aerospace Center (DLR) in Göttingen. The measurement system featured an improved version of a double-shutter camera that was designed to reduce image blur in PSP measurements on fast rotating blades. It also comprised DLR’s PSP sensor, developed to capture transient flow phenomena (iPSP). Unsteady surface pressures were acquired across the outer 65% of the rotor blade with iPSP and at several radial blade sections by fast-response pressure transducers at blade-tip Mach and Reynolds numbers of $$\mathrm {M}_\mathrm{tip} = 0.282-0.285$$ M tip = 0.282 - 0.285 and $$\mathrm {Re}_\mathrm{tip}= 5.84-5.95 \times 10^5$$ Re tip = 5.84 - 5.95 × 10 5 . The unique experimental setup allowed for scanning surface pressures across the entire pitch cycle at a phase resolution of $${0.225}\,{\mathrm{deg}}$$ 0.225 deg azimuth for different collective and cyclic-pitch settings. Experimental results of both investigated cyclic-pitch settings are compared in detail to a delayed detached eddy simulation using the flow solver FLOWer and to flow visualizations from unsteady Reynolds-averaged Navier–Stokes (URANS) computations with DLR’s TAU code. The findings reveal a detailed and yet unseen insight into the pressure footprint of double-swept rotor blades undergoing dynamic stall and allow for deducing “stall maps”, where confined areas of stalled flow on the blade are identifiable as a function of the pitch phase. Graphical abstract

On High-Resolution Pressure Amplitude and Phase Measurements Comparing Fast-Response Pressure Transducers and Unsteady Pressure-Sensitive Paint

2020 ◽  
Author(s):  
Martin Bitter ◽  
Stephan Stotz ◽  
Reinhard Niehuis
Keyword(s):  
Fast Response ◽  
Pressure Amplitude ◽  
Pressure Sensitive Paint ◽  
Simultaneous Application ◽  
Pressure Transducers ◽  
Unsteady Pressure ◽  
Flow Sensing ◽  
Pressure Sensitive ◽  
Perturbation Frequency ◽  
Response Pressure

Abstract This paper presents the simultaneous application of fast-response pressure transducers and unsteady pressure-sensitive paint (unsteady PSP) for the precise determination of pressure amplitudes and phases up to 3,000 Hz. These experiments have been carried out on a low-pressure turbine blade cascade under engine-relevant conditions (Re, Ma, Tu) in the High-Speed Cascade Wind Tunnel. Periodic blade/vane interactions were simulated at the inlet to the cascade using a wake generator operating at a constant perturbation frequency of 500 Hz. The main goal of this paper is the detailed comparison of amplitude and phase distributions between both flow sensing techniques at least up to the second harmonic of the wake generator’s fundamental perturbation frequency (i.e. 1,000 Hz). Therefore, a careful assessment of the key drivers for relative deviations between measurement results as well as a detailed discussion of the data processing is presented for both measurement techniques. This discussion outlines the mandatory steps which were essential to achieve the quality as presented down to pressure amplitudes of several pascal even under challenging experimental conditions. Apart from the remarkable consistency of the results, this paper reveals the potential of (unsteady) PSP as a future key flow sensing technique in turbomachinery research, especially for cascade testing. The results demonstrate that PSP was able to successfully sense pressure dynamics with very low fluctuation amplitudes down to 8 Pa.

Unsteady Pressure Measurement on Oscillating Blade in Transonic Flow Using Fast-Response Pressure-Sensitive Paint

2017 ◽  
Author(s):  
Toshinori Watanabe ◽  
Toshihiko Azuma ◽  
Seiji Uzawa ◽  
Takehiro Himeno ◽  
Chihiro Inoue
Keyword(s):  
Surface Pressure ◽  
Transonic Flow ◽  
Aerodynamic Force ◽  
Fast Response ◽  
Pressure Sensitive Paint ◽  
Unsteady Pressure ◽  
Pressure Distributions ◽  
Pressure Sensitive ◽  
Unsteady Surface Pressure ◽  
Response Pressure

A fast-response pressure-sensitive paint (PSP) technique was applied to the measurement of unsteady surface pressure of an oscillating cascade blade in a transonic flow. A linear cascade was used, and its central blade was oscillated in a translational manner. The unsteady pressure distributions of the oscillating blade and two stationary neighbors were measured using the fast-response PSP technique, and the unsteady aerodynamic force on the blade was obtained by integrating the data obtained on the pressures. The measurements made with the PSP technique were compared with those obtained by conventional methods for the purpose of validation. From the results, the PSP technique was revealed to be capable of measuring the unsteady surface pressure, which is used for flutter analysis in transonic conditions.

Dynamic Calibrations for Fast-Response Porous Polymer/Ceramic Pressure-Sensitive Paint

2013 ◽  
Author(s):  
Ryan M. McMullen ◽  
David P. Huynh ◽  
James Gregory ◽  
Jim W. Crafton
Keyword(s):  
Fast Response ◽  
Porous Polymer ◽  
Pressure Sensitive Paint ◽  
Pressure Sensitive

Investigation of Cavity Flow Using Fast-Response Pressure-Sensitive Paint

AIAA Journal ◽  
2014 ◽  
Vol 52 (11) ◽  
pp. 2462-2470 ◽  
Author(s):  
W. Flaherty ◽  
Todd M. Reedy ◽  
Gregory S. Elliott ◽  
J. M. Austin ◽  
Ryan F. Schmit ◽  
...  
Keyword(s):  
Cavity Flow ◽  
Fast Response ◽  
Pressure Sensitive Paint ◽  
Pressure Sensitive ◽  
Response Pressure

ON HIGH-RESOLUTION PRESSURE AMPLITUDE AND PHASE MEASUREMENTS COMPARING FAST-RESPONSE PRESSURE TRANSDUCERS AND UNSTEADY PRESSURE-SENSITIVE PAINT

2021 ◽  
pp. 1-13
Author(s):  
Martin Bitter ◽  
Stephan Stotz ◽  
Reinhard Niehuis
Keyword(s):  
Second Harmonic ◽  
Measurement Techniques ◽  
Pressure Amplitude ◽  
Pressure Sensitive Paint ◽  
Simultaneous Application ◽  
Pressure Transducers ◽  
Unsteady Pressure ◽  
Flow Sensing ◽  
Pressure Sensitive ◽  
Perturbation Frequency

Abstract This paper presents the simultaneous application of fastresponse pressure transducers and unsteady pressure-sensitive paint (unsteady PSP) for the precise determination of pressure amplitudes and phases up to 3,000 Hz. These experiments have been carried out on a low-pressure turbine blade cascade under engine-relevant conditions (Re, Ma, Tu) in the High-Speed Cascade Wind Tunnel. Periodic blade/vane interactions were simulated at the inlet to the cascade using a wake generator operating at a constant perturbation frequency of 500 Hz. The main goal of this paper is the detailed comparison of amplitude and phase distributions between both flow sensing techniques at least up to the second harmonic of the wake generator's fundamental perturbation frequency (i.e. 1,000 Hz). Therefore, a careful assessment of the key drivers for relative deviations between measurement results as well as a detailed discussion of the data processing is presented for both measurement techniques. This discussion outlines the mandatory steps which were essential to achieve the quality as presented down to pressure amplitudes of several pascal even under challenging experimental conditions. Apart from the remarkable consistency of the results, this paper reveals the potential of (unsteady) PSP as a future key flow sensing technique in turbomachinery research, especially for cascade testing. The results demonstrate that PSP was able to successfully sense pressure dynamics with very low fluctuation amplitudes down to 8 Pa.

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