Eliciting a human understandable model of ice adhesion strength for rotor blade leading edge materials from uncertain experimental data

2012 ◽  
Vol 39 (11) ◽  
pp. 10212-10225 ◽  
Author(s):  
Ana M. Palacios ◽  
José L. Palacios ◽  
Luciano Sánchez
Keyword(s):  
Experimental Data ◽  
Adhesion Strength ◽  
Rotor Blade ◽  
Leading Edge ◽  
Blade Leading Edge ◽  
Ice Adhesion

EFFECT OF AXIAL CASING GROOVE GEOMETRY ON ROTOR-GROOVE INTERACTIONS IN THE TIP REGION OF A COMPRESSOR

2021 ◽  
pp. 1-54
Author(s):  
Subhra Shankha Koley ◽  
Huang Chen ◽  
Ayush Saraswat ◽  
Joseph Katz
Keyword(s):  
Rotor Blade ◽  
Leading Edge ◽  
Secondary Flows ◽  
Low Flow ◽  
Flow Angle ◽  
Flow Rates ◽  
Piv Measurements ◽  
Tip Leakage ◽  
Large Vortex ◽  
Blade Leading Edge

Abstract This experimental study characterizes the interactions of axial casing grooves with the flow in the tip region of an axial turbomachine. The tests involve grooves with the same inlet overlapping with the rotor blade leading edge, but with different exit directions located upstream. Among them, U grooves, whose circumferential outflow opposes the blade motion, achieve a 60% reduction in stall flowrate, but degrade the efficiency around the best efficiency point (BEP) by 2%. The S grooves, whose outlets are parallel to the blade rotation, improve the stall flowrate by only 36%, but do not degrade the BEP performance. To elucidate the mechanisms involved, stereo-PIV measurements covering the tip region and interior of grooves are performed in a refractive index matched facility. At low flow rates, the inflow into both grooves, which peaks when they are aligned with the blade pressure side, rolls up into a large vortex that lingers within the groove. By design, the outflow from S grooves is circumferentially positive. For the U grooves, fast circumferentially negative outflow peaks at the base of each groove, causing substantial periodic variations in the flow angle near the blade leading edge. At BEP, interactions with both grooves become milder, and most of the tip leakage vortex remains in the passage. Interactions with the S grooves are limited hence they do not degrade the efficiency. In contrast, the inflow into and outflow from the U grooves reverses direction, causing entrainment of secondary flows, which likely contribute to the reduced BEP efficiency.

Film-Cooling Prediction on Rotor Blade Leading Edge in 1-1/2 Turbine Stage

2008 ◽  
Vol 22 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Huitao Yang ◽  
Hamn-Ching Chen ◽  
Je-Chin Han ◽  
Hee-Koo Moon
Keyword(s):  
Film Cooling ◽  
Rotor Blade ◽  
Leading Edge ◽  
Turbine Stage ◽  
Blade Leading Edge

Numerical Investigation of the Effect of Rotor Blade Leading Edge Geometry on the Performance of a Variable Geometry Turbine

2012 ◽  
Author(s):  
Lei Huang ◽  
Weilin Zhuge ◽  
Yangjun Zhang ◽  
Liaoping Hu ◽  
Di Yang ◽  
...  
Keyword(s):  
Rotor Blade ◽  
Leading Edge ◽  
Flow Fields ◽  
Operating Conditions ◽  
Angle Distribution ◽  
Variable Geometry ◽  
Sweep Angle ◽  
Turbine Performance ◽  
And Performance ◽  
Blade Leading Edge

Variable geometry turbines are more and more widely used in diesel engines to meet the requirements of the stringent emission standards. The VGTs mostly operate at off-design conditions. At highly off-design conditions, there exist complex secondary flow structures and severe flow separation in the rotor passage, which deteriorate the turbine performance largely. The influence of rotor blade leading edge geometries on the VGT performance was studied by CFD simulations. The blade angle distribution along the leading edge was varied while keeping the radial-fiber rotor construction. The effects of inlet sweep angle distribution and lean angle of the blade leading edge on the turbine flow fields and performance were investigated under different operating conditions. Results show that the turbine with backswept leading edge has better performance at low U/C, while the turbine with forward swept leading edge has a higher efficiency under high flow rate conditions. With the same sweep angle distribution, the leading edge lean affects the flow fields in the rotor passage as well as the turbine performance significantly. The influence of blade lean on the turbine performance varies according to different swept blading and operating conditions.

scholarly journals Icephobic Performance of Multi-Scale Laser-Textured Aluminum Surfaces for Aeronautic Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 135
Author(s):  
Stephan Milles ◽  
Vittorio Vercillo ◽  
Sabri Alamri ◽  
Alfredo I. Aguilar-Morales ◽  
Tim Kunze ◽  
...  
Keyword(s):  
Adhesion Strength ◽  
Leading Edge ◽  
Past Research ◽  
Relative Reduction ◽  
Atmospheric Conditions ◽  
Metallic Surfaces ◽  
Research Activities ◽  
Aerodynamic Performances ◽  
Aluminum Surfaces ◽  
Ice Adhesion

Ice-building up on the leading edge of wings and other surfaces exposed to icing atmospheric conditions can negatively influence the aerodynamic performances of aircrafts. In the past, research activities focused on understanding icing phenomena and finding effective countermeasures. Efforts have been dedicated to creating coatings capable of reducing the adhesion strength of ice to a surface. Nevertheless, coatings still lack functional stability, and their application can be harmful to health and the environment. Pulsed laser surface treatments have been proven as a viable technology to induce icephobicity on metallic surfaces. However, a study aimed to find the most effective microstructures for reducing ice adhesion still needs to be carried out. This study investigates the variation of the ice adhesion strength of micro-textured aluminum surfaces treated using laser-based methods. The icephobic performance is tested in an icing wind tunnel, simulating realistic icing conditions. Finally, it is shown that optimum surface textures lead to a reduction of the ice adhesion strength from originally 57 kPa down to 6 kPa, corresponding to a relative reduction of ~90%. Consequently, these new insights will be of great importance in the development of functionalized surfaces, permitting an innovative approach to prevent the icing of aluminum components.

Evaluation of Ice Adhesion Strength on the Oxidation of Transmission Line ACSR Cable

2019 ◽  
Vol 29 (6) ◽  
pp. 378-384 ◽  
Author(s):  
Hui Jae Cho ◽  
◽  
You Sub Kim ◽  
Yong Chan Jung ◽  
Soo Yeol Lee
Keyword(s):  
Transmission Line ◽  
Adhesion Strength ◽  
Ice Adhesion

Overall Effectiveness for a Film Cooled Turbine Blade Leading Edge With Varying Hole Pitch

2010 ◽  
Author(s):  
Thomas E. Dyson ◽  
Dave G. Bogard ◽  
Justin D. Piggush ◽  
Atul Kohli
Keyword(s):  
Turbine Blade ◽  
Hot Spots ◽  
Leading Edge ◽  
Stagnation Line ◽  
Convective Cooling ◽  
Impingement Cooling ◽  
Blowing Ratio ◽  
Cylindrical Holes ◽  
Overall Effectiveness ◽  
Blade Leading Edge

Overall effectiveness, φ, for a simulated turbine blade leading edge was experimentally measured using a model constructed with a relatively high conductivity material selected so that the Biot number of the model matched engine conditions. The model incorporated three rows of cylindrical holes with the center row positioned on the stagnation line. Internally the model used an impingement cooling configuration. Overall effectiveness was measured for pitch variation from 7.6d to 9.6d for blowing ratios ranging from 0.5 to 3.0, and angle of attack from −7.7° to +7.7°. Performance was evaluated for operation with a constant overall mass flow rate of coolant. Consequently when increasing the pitch, the blowing ratio was increased proportionally. The increased blowing ratio resulted in increased impingement cooling internally and increased convective cooling through the holes. The increased internal and convective cooling compensated, to a degree, for the decreased coolant coverage with increased pitch. Performance was evaluated in terms of laterally averaged φ, but also in terms of the minimum φ. The minimum φ evaluation revealed localized hot spots which are arguably more critical to turbine blade durability than the laterally averaged results. For small increases in pitch there was negligible decrease in performance.

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