New approach to the inspection of cooling holes in aero-engines

Shetty, Devdas; Eppes, Tom; Campana, Claudio; Filburn, Thomas; Nazaryan, Nikolay

doi:10.1016/j.optlaseng.2008.12.001

Cited by 16 publications

(6 citation statements)

References 11 publications

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“…These structures have shown wide applications to fabricate functional materials by controlling the surface properties of electronics, mechanics, wettability, and optical response . Micro/nanoholes array is one of the most actively studied structures due to its extensive applications in making via holes of hand phones and cooling holes of airplane turbine engine . There are two main approaches to produce micro/nanoholes via laser processing.…”

Section: Introductionmentioning

confidence: 99%

Self‐Organized Periodic Microholes Array Formation on Aluminum Surface via Femtosecond Laser Ablation Induced Incubation Effect

Liu

Lin

Zhao

et al. 2019

Adv Funct Materials

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Laser surface structuring has been demonstrated to be a versatile technology to create various functional materials by modifying solid surface properties. An interesting experimental phenomenon of self-organized periodic microholes array formation is demonstrated by exposing an aluminum surface to femtosecond laser irradiation. The microholes with a diameter much smaller than focal laser spot size are produced along laser scan paths due to the incubation effect of multiple laser scans, and they spontaneously form a highly ordered microholes array after 80 scans. It is found that the microhole period and diameter are highly dependent on laser fluence, and controllable microholes arrays with different periods and diameters are achieved by adjusting laser fluence. The physical mechanism behind the formation of the microholes array is attributed to femtosecond laser-induced melting and Marangoni effect. The research provides a novel processing approach to achieve controllable microholes surface materials fabrication at a high speed on metal substrates, which are of great interests for various technological applications.

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Section: Introductionmentioning

confidence: 99%

Self‐Organized Periodic Microholes Array Formation on Aluminum Surface via Femtosecond Laser Ablation Induced Incubation Effect

Liu

Lin

Zhao

et al. 2019

Adv Funct Materials

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“…The 'whisking signal,' u(t), is obtained from the LF voltage signal by multiplying a scaling factor. The HF voltage and current signals are passed through a Hilbert transform in (6) [32] to calculate the temporal signal of the electrical impedance, Z e (t). The temporal signal of the mechanical impedance, Z m (t), is then generated from Z e (t) using equation (5).…”

Section: Bioinspired Location Detectionmentioning

confidence: 99%

“…This configuration is difficult to implement when measuring high aspect ratio microholes, since the laser beam will be obstructed by the sidewalls [5]. It is possible to use optical methods such as laser reflectometry to detect the depth and bottom profile of a blind hole [6,7]. However, these optical methods cannot detect the geometry of the vertical sidewalls since light cannot be reflected back due to the high aspect ratio.…”

Section: Introductionmentioning

confidence: 99%

Bioinspired active whisker sensor for geometry detection of high aspect ratio microholes with simultaneous actuation and sensing capability

Ju¹,

Ling²

2015

Smart Mater. Struct.

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This paper presents a whisker transducer (WT)—inspired by a rat’s vibrissal tactile location perception—that can be used to detect the geometry of high aspect ratio microholes. The WT acts as both the actuator that generates whisking movement and the sensor that detects the mechanical impedance at its tip. This unique, simultaneous actuation-and-sensing capability is achieved through a 2 × 2 transduction matrix model that characterizes both the forward actuation and backward sensing functions of the transducer. The WT imitates a rat’s vibrissal location perception when driven by a special signal with a low-frequency component and a high-frequency component. The low-frequency component plays the role of the ‘whisking signal,’ encoding the whisker position over time, and the high-frequency component plays the role of the ‘touch signal,’ encoding the onset time of mechanical contact. The combination of these two signals allows the WT to detect the location of an object. The proposed transducer and location detection algorithm are validated using a miniature prototype fabricated through micro-EDM process. The achieved geometry measurement capability is of high linearity (R2 > 0.99) and low measurement uncertainty (200 nm). Its potential application in detecting the taper of high aspect ratio microholes is also demonstrated.

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“…This IR camera obtains a sequence of images to analyze and evaluate the thermal cycle situation at the root of the blade. Shetty et al [14] proposed an inspection method, which applied a small collimating tube to illuminate a drilled hole. The presence of a hole's bottom can be measured depending on the reflected intensity and position of the light.…”

Section: Introductionmentioning

confidence: 99%

A novel cooling hole inspection method for turbine blade using 3D reconstruction of stereo vision

Cheng¹,

Li²,

Jiang³

et al. 2021

Meas. Sci. Technol.

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Cooling holes (number 100 ∼ 200, diameter 0.3 ∼ 1.2 mm) are important heat dissipation structures of a turbine blade in aero-engine. Due to the small sizes and similar contours of cooling holes, it is difficult to extract and match their features by traditional stereo reconstruction methods. This paper proposes a novel cooling hole inspection method for turbine blades utilizing 3D reconstruction technique of stereo vision, which combines the stereo vision principle with the invariance of cross-ratio. The feature points of contours are extracted and matched by calculating two intersection points of circular contours and a line through the center points of adjacent cooling holes. Additionally, the 3D points corresponding to the feature points are reconstructed, by which, the diameters of cooling holes can be calculated successfully. Moreover, measurement experiments verify the effectiveness and accuracy of the proposed method. The experimental results show that the average errors of the standard circle ruler and tiny hole sample are within 0.05 mm, which satisfies the inspection requirement of cooling holes.

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New approach to the inspection of cooling holes in aero-engines

Cited by 16 publications

References 11 publications

Self‐Organized Periodic Microholes Array Formation on Aluminum Surface via Femtosecond Laser Ablation Induced Incubation Effect

Self‐Organized Periodic Microholes Array Formation on Aluminum Surface via Femtosecond Laser Ablation Induced Incubation Effect

Bioinspired active whisker sensor for geometry detection of high aspect ratio microholes with simultaneous actuation and sensing capability

A novel cooling hole inspection method for turbine blade using 3D reconstruction of stereo vision

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