Measurement Uncertainty Analysis in Determining Adiabatic Film Cooling Effectiveness by Using Pressure Sensitive Paint Technique

Johnson, Blake; Hu, Hui

doi:10.1115/1.4033506

Cited by 37 publications

(8 citation statements)

References 23 publications

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“…It is well known that the uncertainty of measured film cooling effectiveness by using PSP technique is closely related to the PSP calibration process, quality of the acquired raw images, and the flow conditions of the mainstream and coolant streams. Following up the work of Johnson & Hu [28], the absolute measurement uncertainty of the present study was estimated to be within 0.02…”

Section: Figure 3 Experimental Setup Used For Film Cooling Effectivementioning

confidence: 87%

“…In the present study, as suggested by Johnson & Hu [28], a spatially-averaging procedure with interrogation windows of 9×9 pixels and 50% overlap rate was performed for the acquired PSP images, in order to minimize the measurement uncertainties,. Since the acquired PSP images had a magnification of 0.07 mm/pix, the spatial resolution of the PSP measurement results would be about 0.30 mm (i.e., ~ 0.07D).…”

Section: Figure 3 Experimental Setup Used For Film Cooling Effectivementioning

confidence: 99%

“…, and the corresponding relative uncertainty is within 5% for 0.6   and 7% for 0.4   .These uncertainty values were estimated based on a Taylor Series Method [29,30]. Further details about the uncertainty analysis of the measured film cooling effectiveness by using PSP technique can be found in Johnson & Hu [28].…”

Section:  mentioning

confidence: 99%

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Improvements of film cooling effectiveness by using Barchan dune shaped ramps

Zhou

2016

International Journal of Heat and Mass Transfer

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In the present study, an experimental investigation was conducted to explore a novel film cooling design with Barchan-dune-shaped-ramp (BDSR) concept to augment the effectiveness of film cooling injection from discrete holes. Inspired by the unique shape of Barchan dunes commonly seen in deserts to prevent sand particles on the ground from being blown away by the oncoming airflow, the BDSR concept was proposed to enable the coolant streams exhausted from coolant injection holes stay more firmly over the surface of interest for improved film cooling performance. During the experiments, while coolant streams were injected from discrete circular holes on a flat test plate at an injection angle of 35 degrees, a row of BDSRs were mounted on the test plate at either downstream or upstream of the coolant injection holes for improved film cooling effectiveness. While a high-resolution Particle Image Velocimetry (PIV) system was used to conduct detailed flow field measurements to quantify the dynamic mixing process between the coolant jet streams and the mainstream flows over the test plate, a Pressure Sensitive Paint (PSP) technique was used to map the corresponding adiabatic film cooling effectiveness on the surface of interest based on a mass-flux analog to traditional temperature-based cooling effectiveness measurements. The cooling effectiveness data of the BDSR design were compared quantitatively against those of a conventional film cooling design without BDSR (i.e., baseline case) under the same test conditions in order to evaluate the effects of the BDSRs on the film cooling effectiveness over the surface of interest. The effects of the locations and height of the BDSRs in relation to the coolant injection holes on the film cooling effectiveness at different blowing ratios (i.e., the coolant-to-mainstream mass flux ratios) were examined quantitatively based on the PIV and PSP measurements. The detailed flow field measurements were correlated with the measured film cooling effectiveness distributions to elucidate the underlying physics in order to explore/optimize design paradigms for better film cooling protection of turbine blades from harsh environments.

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Section: Figure 3 Experimental Setup Used For Film Cooling Effectivementioning

confidence: 87%

Section: Figure 3 Experimental Setup Used For Film Cooling Effectivementioning

confidence: 99%

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Improvements of film cooling effectiveness by using Barchan dune shaped ramps

Zhou

2016

International Journal of Heat and Mass Transfer

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“…It should be noted that the uncertainty of measured film cooling effectiveness by using PSP technique is closely related to PSP calibration process, quality of the acquired raw images, and the flow conditions of the mainstream and coolant streams. Following up the work of Johnson & Hu [22], the absolute measurement uncertainty of the present study was estimated to be within for the measured centerline film cooling effectiveness. The relative measurement uncertainty is estimated to be within 3% for and 5% for .…”

Section: Adiabatic Film Cooling Effectiveness Measurement By Using Psp Techniquementioning

confidence: 99%

A novel sand-dune-inspired design for improved film cooling performance

Zhou

2017

International Journal of Heat and Mass Transfer

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An experimental study was performed to explore a novel film cooling design with a Barchan-Dune-Shaped Injection Compound (BDSIC) concept for improved film cooling performance over a test plate. Inspired by the unique crescent-shaped Barchan dunes commonly seen in deserts, the BDSIC concept was proposed to enable coolant streams to be discharged tangentially from hollowed Barchan-dune-shaped (BDS) shells and stay attached to the surface of the test plate. During the experiments, while a highresolution Particle Image Velocimetry (PIV) system was used to conduct detailed flow field measurements to quantify the dynamic mixing process between the coolant stream and the mainstream flows over the test plate, a Pressure Sensitive Paint (PSP) technique was used to map the corresponding adiabatic film cooling effectiveness over the surface of interest based on a mass-flux analog to traditional temperature-based cooling effectiveness measurements.The effects of various important design parameters, including the shape of the BDS shells, the blowing ratio of the coolant streams, and the spanwise distance (i.e., the pitch) between the neighboring BDSICs, on the film cooling performance were evaluated in great detail based the quantitative PSP and PIV measurements. It was found that, in comparison with that of conventional film cooling design with coolant stream injected from circular hole (i.e., the baseline case), the film cooling effectiveness over the test plate would be enhanced significantly (i.e., 30% ~ 500%) by using the BDSIC design, especially for the test case with elongated BDS shells. As expected, the BDSIC design was found to cause a higher aerodynamic loss at relatively low blowing ratios, due to a greater friction loss associated with its complex shape. However, since the unique BDSIC design could keep the coolant stream to stay attached more firmly on the surface of the test plate (i.e., reducing the aerodynamic loss associated with the penetration of the coolant streams into the mainstream flow), the aerodynamic loss of the BDSIC design was found to become even smaller than that of the conventional film cooling design with circular hole design at relatively high blowing ratios. Keywords: Film cooling; Barchan dune inspired film cooling design; Counter rotating vortex structures; PIV measurements, PSP technique; Mass transfer analog in determining film cooling effectiveness; Aerodynamic loss of film cooling design.

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“…To know more about this fairly new technique, detailed uncertainty analysis has been performed to evaluate the effects of various uncertainties in PSP measurements on the distribution of  over the surface of interest [11,12]: the main outcome consisted in experimental procedures or guidelines to achieve high-accuracy  measurements. Instead, Wiese et al [13] focused on the suitability of the heat-mass transfer analogy when employing PSP to portray leading edge film cooling.…”

Section: Introductionmentioning

confidence: 99%