A Quantitative Investigation of Surface Roughness Effects on Airfoil Boundary Layer Transition Using Infrared Thermography

2016 ◽  
Author(s):  
Todd Beeby ◽  
Jan Ackermann ◽  
Christopher M. Langel ◽  
Raymond Chow ◽  
Case (CP) P. Van Dam ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Infrared Thermography ◽  
Boundary Layer Transition ◽  
Quantitative Investigation ◽  
Roughness Effects ◽  
Layer Transition

A Review of Surface Roughness Effects in Gas Turbines

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
J. P. Bons
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Surface Roughness ◽  
Gas Turbines ◽  
Engine Performance ◽  
Boundary Layer Transition ◽  
Roughness Effects ◽  
Layer Transition ◽  
Laminar Separation

The effects of surface roughness on gas turbine performance are reviewed based on publications in the open literature over the past 60 years. Empirical roughness correlations routinely employed for drag and heat transfer estimates are summarized and found wanting. No single correlation appears to capture all of the relevant physics for both engineered and service-related (e.g., wear or environmentally induced) roughness. Roughness influences engine performance by causing earlier boundary layer transition, increased boundary layer momentum loss (i.e., thickness), and/or flow separation. Roughness effects in the compressor and turbine are dependent on Reynolds number, roughness size, and to a lesser extent Mach number. At low Re, roughness can eliminate laminar separation bubbles (thus reducing loss) while at high Re (when the boundary layer is already turbulent), roughness can thicken the boundary layer to the point of separation (thus increasing loss). In the turbine, roughness has the added effect of augmenting convective heat transfer. While this is desirable in an internal turbine coolant channel, it is clearly undesirable on the external turbine surface. Recent advances in roughness modeling for computational fluid dynamics are also reviewed. The conclusion remains that considerable research is yet necessary to fully understand the role of roughness in gas turbines.

Infrared thermography of hypersonic boundary layer transition induced by isolated roughness elements

2021 ◽  
Author(s):  
Shicheng Liu ◽  
Meng Wang ◽  
Hao Dong ◽  
Tianyu Xia ◽  
Lin Chen ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Infrared Thermography ◽  
Roughness Element ◽  
Transition Process ◽  
Boundary Layer Transition ◽  
Hypersonic Boundary Layer ◽  
Layer Transition ◽  
Leading Role ◽  
Roughness Elements ◽  
Element Shape

Roughness element induced hypersonic boundary layer transition on a flat plate is investigated using infrared thermography at Ma = 5 and 6 flow condition. Surface Stanton number is acquired to analyze the effect of roughness element shape and height on the transition process. The correlation between the vortex structure induced by roughness element and the wall heat streaks is established. The results indicate that higher roughness element would induce stronger streamwise heat flux streaks, lead to transition advance in streamwise centerline and increase the width of spanwise wake. Moreover, for low roughness element, the effect of the shape is not obvious, and the height plays a leading role in the transition; for tall roughness element, the effect on accelerating transition for the diamond roughness element is the best, the square is the worst, and the shape plays a leading role in the transition.

HIFiRE-5 Boundary-Layer Transition Measured in a Mach-6 Quiet Tunnel with Infrared Thermography

AIAA Journal ◽  
2019 ◽  
Vol 57 (5) ◽  
pp. 2001-2010 ◽  
Author(s):  
Thomas J. Juliano ◽  
Laura A. Paquin ◽  
Matthew P. Borg
Keyword(s):  
Boundary Layer ◽  
Infrared Thermography ◽  
Boundary Layer Transition ◽  
Layer Transition

Advanced infrared thermography data analysis for unsteady boundary layer transition detection

2019 ◽  
Vol 31 (1) ◽  
pp. 015301 ◽  
Author(s):  
C Mertens ◽  
C C Wolf ◽  
A D Gardner ◽  
F F J Schrijer ◽  
B W van Oudheusden
Keyword(s):  
Boundary Layer ◽  
Data Analysis ◽  
Infrared Thermography ◽  
Boundary Layer Transition ◽  
Unsteady Boundary Layer ◽  
Layer Transition

Effect of Surface Roughness on Conjugate Heat Transfer of a Turbine Vane

2016 ◽  
Author(s):  
Hongyang Li ◽  
Yun Zheng
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Surface Roughness ◽  
Suction Side ◽  
Transition Process ◽  
Considerable Effect ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Turbine Vane ◽  
Effect Of Surface

For the purpose of researching the effect of surface roughness on boundary layer transition and heat transfer of turbine blade, a roughness modification approach for γ-Reθ transition model was proposed based on an in-house CFD code. Taking surface roughness effect into consideration, No. 5411 working condition of Mark II turbine vane was simulated and the results were analyzed in detail. Main conclusions are as follows: Surface roughness has little effect on heat transfer of laminar boundary layer, while has considerable effect on turbulent boundary layer. Compared with smooth surface, equivalent sand roughness of 100μm increases the temperature for about 28.4K on suction side, reaching an increase of 5%. Under low roughness degree, effect of shock wave dominants on boundary layer transition process on suction side, while above the critical degree, effect of surface roughness could abruptly change the transition point.

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