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1
Chen, Yan, Chunxiang Gao i Wuli Chu. "Effect and Mechanism of Roughness on the Performance of a Five-Stage Axial Flow Compressor". Aerospace 9, nr 8 (4.08.2022): 428. http://dx.doi.org/10.3390/aerospace9080428.
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In order to prolong the service life of multistage axial compressors, it is increasingly important to study the influence of blade surface roughness on the compressor performance. In this paper, a five-stage axial compressor of a real aero-engine was selected as the research object, and an equivalent gravel roughness model was used to model the roughness based on measured blade surface roughness data. Furthermore, the impact of blade surface roughness on the performance at design rotational speed was studied by full three-dimensional numerical simulation, and the mechanism of performance variation caused by the roughness was discussed combined with quantitative and flow field analyses. The results show that, when the blade surface roughness of all blades increases, the peak total efficiency decreases by approximately 0.4%, the blocking mass-flow decreases by approximately 0.3%, and the stable working range changes little. When the surface roughness of all rotor blades increases, the performance decline is close to that of all rotor and stator blades, and the variation in stator blade roughness has little effect on the compressor performance. Regarding the variation in roughness, the performance of the latter stage is more sensitive than that of the previous stage, and the decline in the performance of the fifth stage contributes the most to the total performance degradation of the compressor. Once the surface roughness of the fifth-stage rotor blade increases, the flow in the middle of the rotor blade deteriorates and the stage performance decreases obviously, which is the main reason for the decline in the overall performance.
2
Yun, Yong Il, Il Young Park i Seung Jin Song. "Performance Degradation due to Blade Surface Roughness in a Single-Stage Axial Turbine". Journal of Turbomachinery 127, nr 1 (1.01.2005): 137–43. http://dx.doi.org/10.1115/1.1811097.
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Turbine blades experience significant surface degradation with service. Previous studies indicate that an order-of-magnitude or greater increase in roughness height is typical, and these elevated levels of surface roughness significantly influence turbine efficiency and heat transfer. This paper presents measurement and a mean-line analysis of turbine efficiency reduction due to blade surface roughness. Performance tests have been conducted in a low-speed, single-stage, axial flow turbine with roughened blades. Sheets of sandpaper with equivalent sandgrain roughnesses of 106 and 400 μm have been used to roughen the blades. The roughness heights correspond to foreign deposits on real turbine blades measured by Bons et al. [1]. In the transitionally rough regime (106 μm), normalized efficiency decreases by approximately 4% with either roughened stator or roughened rotor and by 8% with roughness on both the stator and rotor blades. In the fully rough regime (400 μm), normalized efficiency decreases by 2% with roughness on the pressure side and by 6% with roughness on the suction side. Also, the normalized efficiency decreases by 11% with roughness only on stator vanes, 8% with roughness only on rotor blades, and 19% with roughness on both the stator and rotor blades.
3
Liu, Chen, Yipeng Cao, Sihui Ding, Wenping Zhang, Yuhang Cai i Aqiang Lin. "Effects of blade surface roughness on compressor performance and tonal noise emission in a marine diesel engine turbocharger". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 234, nr 14 (9.06.2020): 3476–90. http://dx.doi.org/10.1177/0954407020927637.
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A numerical study was conducted to investigate the effects of blade surface roughness on compressor performance and tonal noise emission. The equivalent sand-grain roughness model was used to account for blade surface roughness, and a hybrid method that combines computational fluid dynamics and boundary element method was used to predict compressor performance and tonal noise. The numerical approach was validated against experimental data for a baseline compressor. Nine different cases with different blade surface roughness were studied in this paper, the global performance was analyzed under compressor design speed, and the tonal noise level was predicted under the design condition. The results indicate that compressor total-to-total pressure ratio and isentropic efficiency were gradually decreased with the increasing blade surface roughness. Besides, the blade total pressure loss coefficient and the efficiency loss coefficient were also increased. It was found that the reverse flow at the leading edge of compressor rotor blades reduced blade loading. The pressure fluctuation at the leading edge showed that the peak of pressure fluctuations increased as the blade surface roughness was increased. The sound pressure level at blade-passing frequency shows a significant change with variation in blade surface roughness, which results in an increased total noise level. Furthermore, it was shown that the blade surface roughness had nearly no influence on acoustic directivity, but the sound pressure level increased with the increase in roughness, especially at blade-passing frequency.
4
Tangler, J. L. "Influence of Pitch, Twist, and Taper on a Blade’s Performance Loss due to Roughness". Journal of Solar Energy Engineering 119, nr 3 (1.08.1997): 248–52. http://dx.doi.org/10.1115/1.2888027.
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The purpose of this study was to determine the influence of blade geometric parameters such as pitch, twist, and taper on a blade’s sensitivity to leading edge roughness. The approach began with an evaluation of available test data of performance degradation due to roughness effects for several rotors. In addition to airfoil geometry, this evaluation suggested that a rotor’s sensitivity to roughness was also influenced by the blade geometric parameters. Parametric studies were conducted using the PROP93 computer code with wind tunnel airfoil characteristics for smooth and rough surface conditions to quantify the performance loss due to roughness for tapered and twisted blades relative to a constant-chord nontwisted blade at several blade pitch angles. The results indicate that a constant-chord nontwisted blade pitched toward stall will have the greatest losses due to roughness. The use of twist, taper, and positive blade-pitch angles all help reduce the angle-of-attack distribution along the blade for a given wind speed and the associated performance degradation due to roughness.
5
Özgen, Serkan, Eda Bahar Sarıbel i Ali Rıza Yaman. "Effect of blade contamination on power production of wind turbines". Journal of Physics: Conference Series 2265, nr 3 (1.05.2022): 032012. http://dx.doi.org/10.1088/1742-6596/2265/3/032012.
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Abstract Wind turbines suffer from considerable power losses because of contamination on their blades, that can be due to erosion, wear, smog, insect, sand and dust particle impact. Blade contamination, its effects on the flows over the wind turbine blades and consequent power production losses form the main focus of the present study. These effects are mainly due to increased roughness on the blades leading to earlier laminar-turbulent transition and consequently, thicker boundary-layers on the blades. Early laminar-turbulent transition leads to a larger part of the flow over a blade being turbulent, thus increasing skin friction drag. Thicker boundary-layer on a blade results in blade profile being effectively modified, rendering the flow over the blade depart from ideal. In the present study, the effects of blade contamination on power output of contaminated wind turbine blades is investigated numerically using an in-house computational tool. Blade Element Momentum Method (BEM) combined with the Panel Method is used to calculate the local velocity and angle of attack at the blade sections, together with the power produced by the blade. Trajectories of particles causing contamination are calculated using Lagrangian approach, also yielding the impingement pattern of the particles on the blade surface, i.e. particle collection efficiency distribution. The effects of roughness on the boundary-layer flow are investigated by using an Integral Boundary-Layer Method, which yields the characteristics of the boundary-layer, i.e. laminar-turbulent transition location, increased skin-friction and thickening of the boundary-layer. The blade shape is modified due contamination thickness, the local height of which is assumed to be proportional to the local collection efficiency. Also, the roughness height distribution used in the boundary-layer calculations is assumed to be equal to the contamination thickness distribution on the blades. Power production and consequent losses of wind turbines with contaminated wind turbine blades are studied with respect to variations in particle size, wind speed and roughness height.
6
Mulleners, K., P. Gilge i S. Hohenstein. "Impact of Surface Roughness on the Turbulent Wake Flow of a Turbine Blade". Journal of Aerodynamics 2014 (30.12.2014): 1–9. http://dx.doi.org/10.1155/2014/458757.
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Roughened aeroengine blade surfaces lead to increased friction losses and reduced efficiency of the individual blades. The surface roughness also affects the wake flow of the blade and thus the inflow conditions for the subsequent compressor or turbine stage. To investigate the impact of surface roughness on a turbulent blade wake, we conducted velocity field measurements by means of stereo particle image velocimetry in the wake of a roughened turbine blade in a linear cascade wind tunnel. The turbine blade was roughened at different chordwise locations. The influence of the chordwise location of the added surface roughness was examined by comparing their impact on the width and depth of the wake and, the positions and distribution of vortical structures in the wake. Additionally, the friction loss coefficients for different surface roughness positions were estimated directly from the velocity field.
7
Gutiérrez, R., E. Llorente i D. Ragni. "Induced stalled flow due to roughness sensitivity for thick airfoils in modern wind turbines". Journal of Physics: Conference Series 2151, nr 1 (1.01.2022): 012001. http://dx.doi.org/10.1088/1742-6596/2151/1/012001.
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Abstract The mid-span region of wind turbine blades can be thickened to fulfil the structural requirements of the blade. Hence, thick airfoils, that were designed to operate at the root region of the blade, are moved to the mid-span region. This could not imply remarkable variations of the blade performance once its surface is smooth. However, the sensitivity of thick airfoils to roughness could cause significant aerodynamic impacts such as flow separation. This research aims to quantify the impact of the blade thickness, under smooth and rough conditions, in the annual energy production and the fatigue loads of the blade. Ten blade designs, linearly interpolated in thickness, are studied employing aero-elastic computations. The results reveal that the thickest blade increases the annual energy production by 5% with respect to the thinnest blade under rough conditions. Whereas this increase is less than 1% under smooth conditions. The loss of annual energy production varies with the blade thickness linearly for thin blades while it varies exponentially for thick blades up to 22%. Fatigue loads assessment confirmed a reduction of the damage equivalent load under smooth conditions, whereas the thickest blade increased it 28% under rough conditions.
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Gilge, Philipp, Andreas Kellersmann, Jens Friedrichs i Jörg R. Seume. "Surface roughness of real operationally used compressor blade and blisk". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, nr 14 (9.05.2019): 5321–30. http://dx.doi.org/10.1177/0954410019843438.
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Deterioration of axial compressors is in general a major concern in aircraft engine maintenance. Among other effects, roughness in high-pressure compressor reduces the pressure rise and thus efficiency, thereby increasing the specific fuel consumption of an engine. Therefore, it is important to improve the understanding of roughness on compressor blading and their impact on compressor performance. To investigate the surface roughness of rotor blades of a compressors, different stages of an axial high-pressure compressor and a first-stage blisk (BLade–Integrated–dISK) of a regional aircraft engine is measured by a three-dimensional laser scanning microscope. Fundamental types of roughness structures can be identified: impacts in different sizes, depositions as isotropically distributed single elements with steep flanks and anisotropic roughness structures direct approximately normal to the flow direction. To characterise and quantify the roughness structures in more detail, roughness parameters were determined from the measured surfaces. The quantification showed that the roughness height varies through the compressor depending on the stage, position and the blade side. Overall complex roughness structures of different shape, height and size are detected regardless of the type of the blades.
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Caccia, Francesco, i Alberto Guardone. "Numerical simulations of ice accretion on wind turbine blades: are performance losses due to ice shape or surface roughness?" Wind Energy Science 8, nr 3 (15.03.2023): 341–62. http://dx.doi.org/10.5194/wes-8-341-2023.
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Abstract. Ice accretion on wind turbine blades causes both a change in the shape of its sections and an increase in surface roughness. These lead to degraded aerodynamic performances and lower power output. Here, a high-fidelity multi-step method is presented and applied to simulate a 3 h rime icing event on the National Renewable Energy Laboratory 5 MW wind turbine blade. Five sections belonging to the outer half of the blade were considered. Independent time steps were applied to each blade section to obtain detailed ice shapes. The roughness effect on airfoil performance was included in computational fluid dynamics simulations using an equivalent sand-grain approach. The aerodynamic coefficients of the iced sections were computed considering two different roughness heights and extensions along the blade surface. The power curve before and after the icing event was computed according to the Design Load Case 1.1 of the International Electrotechnical Commission. In the icing event under analysis, the decrease in power output strongly depended on wind speed and, in fact, tip speed ratio. Regarding the different roughness heights and extensions along the blade, power losses were qualitatively similar but significantly different in magnitude despite the well-developed ice shapes. It was found that extended roughness regions in the chordwise direction of the blade can become as detrimental as the ice shape itself.
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Hamed, Awatef A., Widen Tabakoff, Richard B. Rivir, Kaushik Das i Puneet Arora. "Turbine Blade Surface Deterioration by Erosion". Journal of Turbomachinery 127, nr 3 (1.03.2004): 445–52. http://dx.doi.org/10.1115/1.1860376.
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This paper presents the results of a combined experimental and computational research program to investigate turbine vane and blade material surface deterioration caused by solid particle impacts. Tests are conducted in the erosion wind tunnel for coated and uncoated blade materials at various impact conditions. Surface roughness measurements obtained prior and subsequent to the erosion tests are used to characterize the change in roughness caused by erosion. Numerical simulations for the three-dimensional flow field and particle trajectories through a low-pressure gas turbine are employed to determine the particle impact conditions with stator vanes and rotor blades using experimentally based particle restitution models. Experimental results are presented for the measured blade material/coating erosion and surface roughness. The measurements indicate that both erosion and surface roughness increase with impact angle and particle size. Computational results are presented for the particle trajectories through the first stage of a low-pressure turbine of a high bypass turbofan engine. The trajectories indicate that the particles impact the vane pressure surface and the aft part of the suction surface. The impacts reduce the particle momentum through the stator but increase it through the rotor. Vane and blade surface erosion patterns are predicted based on the computed trajectories and the experimentally measured blade coating erosion characteristics.
11
Liu, Yue, Zhanqiang Liu, Wentong Cai, Yukui Cai, Bing Wang i Guoying Li. "Optimisation of Planning Parameters for Machining Blade Electrode Micro-Fillet with Scallop Height Modelling". Micromachines 12, nr 3 (26.02.2021): 237. http://dx.doi.org/10.3390/mi12030237.
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Aero-engine blades are manufactured by electroforming process with electrodes. The blade electrode is usually machined with five-axis micromilling to get required profile roughness. Tool path planning parameters, such as cutting step and tool tilt angle, have a significant effect on the profile roughness of the micro-fillet of blade electrode. In this paper, the scallop height model of blade electrode micro-fillet processed by ball-end milling cutter was proposed. Effects of cutting step and tool tilt angle the machined micro-fillet profile roughness were predicted with the proposed scallop height model. The cutting step and tool tilt angle were then optimised to ensure the contour precision of the micro-fillet shape requirement. Finally, the tool path planning was generated and the machining strategy was validated through milling experiments. It was also found that the profile roughness was deteriorated due to size effect when the cutting step decreased to a certain value.
12
Cai, Yong Lin, i Di Yao. "Research on Surface Roughness Experiment of Flank Milling for the Ruled Surface Blade". Advanced Materials Research 602-604 (grudzień 2012): 2027–30. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.2027.
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In this paper, the factors affecting the surface roughness by flank milling are selected, and the blade machining experiments are implemented according to the orthogonal table designed, Then, the blade surface roughness are measured using TR200 instrument, and the surface roughness of the blade results are analyzed using visual analysis method and variance analysis method. Finally, the impact of various factors on the blade roughness is obtained, and the optimal process parameters of flank milling aluminum alloy blade are given.
13
Nosov, Nicolay V. "Study of surface quality using quasi-optimal correlation algorithms". MATEC Web of Conferences 224 (2018): 01077. http://dx.doi.org/10.1051/matecconf/201822401077.
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The article proposes a new approach for evaluating roughness of the profile surface of gas turbine engine blade airfoils after vibratory polishing. An optical electronic unit was used to study microgeometry of blade suction and pressure sides: video imagery of the surface was processed using computer methods to obtain the average amplitude of the autocorrelation function variable component. The applied optical electronic method of evaluating microgeometry of compressor/turbine blades allows obtaining fields of surface roughness and tension concentration coefficients as well as analyzing the finish machining technology to a greater depth.
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Suder, K. L., R. V. Chima, A. J. Strazisar i W. B. Roberts. "The Effect of Adding Roughness and Thickness to a Transonic Axial Compressor Rotor". Journal of Turbomachinery 117, nr 4 (1.10.1995): 491–505. http://dx.doi.org/10.1115/1.2836561.
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The performance deterioration of a high-speed axial compressor rotor due to surface roughness and airfoil thickness variations is reported. A 0.025 mm (0.001 in.) thick rough coating with a surface finish of 2.54–3.18 rms μm (100–125 rms μin.) is applied to the pressure and suction surface of the rotor blades. Coating both surfaces increases the leading edge thickness by 10 percent at the hub and 20 percent at the tip. Application of this coating results in a loss in efficiency of 6 points and a 9 percent reduction in the pressure ratio across the rotor at an operating condition near the design point. To separate the effects of thickness and roughness, a smooth coating of equal thickness is also applied to the blade. The smooth coating surface finish is 0.254–0.508 rms μm (10–20 rms μin.), compared to the bare metal blade surface finish of 0.508 rms pm (20 rms μin.). The smooth coating results in approximately half of the performance deterioration found from the rough coating. Both coatings are then applied to different portions of the blade surface to determine which portions of the airfoil are most sensitive to thickness/roughness variations. Aerodynamic performance measurements are presented for a number of coating configurations at 60, 80, and 100 percent of design speed. The results indicate that thickness/roughness over the first 2 percent of blade chord accounts for virtually all of the observed performance degradation for the smooth coating, compared to about 70 percent of the observed performance degradation for the rough coating. The performance deterioration is investigated in more detail at design speed using laser anemometer measurements as well as predictions generated by a quasi-three-dimensional Navier–Stokes flow solver, which includes a surface roughness model. Measurements and analysis are performed on the baseline blade and the full-coverage smooth and rough coatings. The results indicate that adding roughness at the blade leading edge causes a thickening of the blade boundary layers. The interaction between the rotor passage shock and the thickened suction surface boundary layer then results in an increase in blockage, which reduces the diffusion level in the rear half of the blade passage, thus reducing the aerodynamic performance of the rotor.
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Gao, Hang, Z. Zhao i Y. W. Sun. "Recent Development of the Aero-Engine Impeller and Blade Surface Polishing Technology". Advanced Materials Research 135 (październik 2010): 7–12. http://dx.doi.org/10.4028/www.scientific.net/amr.135.7.
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The air compressing efficiency and heat conductance of aero-engine is markedly influenced by the surface micro-morphology and surface roughness of the impeller and blades, which will further affect the thrust weight ratio of plane. To achieve low flow losses, the roughness values of the impeller and blade surface must be below certain limits. Some polishing techniques as final finishing process of the impeller and blades are reviewed and their recent developments are shown in the paper. Further more a new kind of point-by-point NC polishing principle for aero-engine impeller surface, in which surface roughness will gradually change from the inlet to the outlet, are presented.
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Degrazia, Felipe Weidenbach, Bruna Genari, Vilmar Antonio Ferrazzo, Ary dos Santos-Pinto i Renésio Armindo Grehs. "Enamel Roughness Changes after Removal of Orthodontic Adhesive". Dentistry Journal 6, nr 3 (6.08.2018): 39. http://dx.doi.org/10.3390/dj6030039.
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The aim of this study was to evaluate enamel roughness, quality of the enamel surfaces and time duration comparing different orthodontic adhesive removal protocols. Premolars were used to test three adhesive removal methods (n = 20): five-blade carbide bur, 30-blade carbide bur, and ultrasonic diamond bur. Bracket was bonded using TransbondTM XT adhesive. Roughness with different parameters was measured before bracket bonding and after adhesive remnants removal. Micromorphological analysis of enamel surface (n = 5) was performed by SEM images and categorized in enamel damage index—“perfect”; “satisfying”; “imperfect”; and “unacceptable”. Time was measured in seconds. All removal methods caused increased roughness in relation to Ra, Rq, and Rz parameters (X axis) comparing to healthy enamel surface. Enamel surface resulted from removal using five-blade burs was scored as satisfactory. Carbide bur groups decreased the roughness values of Ra, Rq, and Rz parameters on the Y axis and enamel surface was considered unacceptable. The 30-blade group increased symmetry (Rsk) and flattening (Rku) parameters of roughness and surface was scored as unsatisfactory. Diamond bur removed adhesive in 54.8 s, faster than five-blade carbide bur. The five-blade bur group resulted in less enamel roughness than the 30-blade and diamond groups.
17
Taylor, R. P. "Surface Roughness Measurements on Gas Turbine Blades". Journal of Turbomachinery 112, nr 2 (1.04.1990): 175–80. http://dx.doi.org/10.1115/1.2927630.
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Results are presented from profilometer measurements of the surface roughness on in-service turbine engine blades from F-100 and TF-39 aeroengines. On each blade, one roughness profile is taken in the region of the leading edge, the midchord and the trailing edge on both the pressure and suction sides for a total of six profiles. Thirty first-stage turbine blades are measured from each engine. Statistical computations are performed on these profiles and the root mean square height, skewness and kurtosis of the roughness height distribution are presented along with the correlation length of the autocorrelation function. The purpose of this work is to provide insight into the nature of surface roughness characteristics of in-service turbine blades which can be used in the development of scaled laboratory experiments of boundary layer flow and heat transfer on turbine engine blades.
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Loboda, A. A., S. A. Mozgov i B. P. Saushkin. "Electrochemical finishing of airfoil blade wheels". Izvestiya MGTU MAMI 7, nr 2-2 (20.03.2013): 251–57. http://dx.doi.org/10.17816/2074-0530-68287.
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The article describes the change in the basic manufacture technology of the blades closed blade wheels through the use of finishing operations to remove the defective layer and to reduce the surfaces roughness of the blades after electroerosive firmware operation. The efficiency of the new operation instead of the original is based on a manual finishing of blade profile was confirmed by experimental studies. The article describes the experiments on the selection of the optimum parameters of the processing and selection of the optimal electrolyte. It also shows the effect of various parameters of the processing mode on the surface microgeometry formation during processing.
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Han, Xu, Xiangyu Liu, Yunyun Yuan i Zhonghe Han. "Effect of blade surface roughness on condensation process in a stator cascade". International Journal of Numerical Methods for Heat & Fluid Flow 30, nr 8 (7.12.2019): 4067–81. http://dx.doi.org/10.1108/hff-10-2019-0736.
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Purpose The flow state of wet steam will affect the thermodynamic and aerodynamic characteristics of steam turbine. The purpose of this study is to effectively control the wetness losses caused by wet steam condensation, and hence a cascade of 600 MW steam turbine was taken as the research object. Design/methodology/approach The influence of blade surface roughness on the condensation characteristics was analyzed, and the dehumidification mechanism and wetness control effect were obtained. Findings With the increase of blade surface roughness, the peak nucleation rate decreases gradually. According to the Mach number distribution on the blade surface, there is a sensitive region for the influence of roughness on the aerodynamic performance of cascade. The sensitive region of nucleation rate roughness should be between 50 and 150 µm. Originality/value The increase of blade surface roughness will increase the dynamic loss in cascade, but it can reduce the thermodynamic loss caused by condensation to a certain extent.
20
Qiu, Lei, Liangtao Qi, Lanlan Liu, Zhu Zhang i Jianwei Xu. "The blade surface performance and its robotic machining". International Journal of Advanced Robotic Systems 17, nr 2 (1.03.2020): 172988142091409. http://dx.doi.org/10.1177/1729881420914090.
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Through numerical calculations, it could be found that when the blade surface quality reaches a certain level, the surface quality of the blade was continuously improved, and the guarantee effect on its performance would be weakened. Under this circumstance, continuing to improve the surface quality of the blade had no positive effect on the performance of the blade. Studies had shown that when the blade surface equivalent grit roughness Ks reaches 4.96 (about R a = 0.8 µm), the blade performance was close to the smooth surface of the blade, and no further processing was required to improve the surface roughness. When the surface equivalent grit Ks was greater than 4.96 µm, the surface roughness had a great influence on the blade performance. When Ks was larger than 40 µm, the negative effect is significantly increased. For the different characteristics of the blade and different processing conditions, four kinds of robot-based blade surface grinding schemes were proposed, of which the core content was the robot layout. Based on the robot group’s fitting to the spatial surface and the path planning, the experimental verification was carried out.
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Li, Da Qi, Lei Zhang, Wei Dong Ye i Hai Ying Zu. "Research on Path of Contact Wheel for Ruled Blade Grinding". Applied Mechanics and Materials 536-537 (kwiecień 2014): 1343–46. http://dx.doi.org/10.4028/www.scientific.net/amm.536-537.1343.
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Blade is one of the important components in aero-engine, turbine, and wind generators. The quality of the blades has big influence on the performance of the machine. So high profile accuracy and low surface roughness were put forward. Ruled blade is just one of the blades of aero-engine, which has simple profile and little distort. This blade was grinded by two sides together in the paper. Therefore, in this thesis, the main objects are as fallow: firstly, according to the characteristics of the abrasive belt grinding, analysis the selection of grinding distance for the blade. Secondly, established the model of contact wheel compare grinding system, derived the range of wrap angle of contact wheel, and then two region were make out, one is the region can be directly grinding, and another region which may lead to wheel interference. At last the grinding path of the center of the contact wheel was obtained by calculated the blade model.
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Nielsen, Mikkel Schou, Ivan Nikolov, Emil Krog Kruse, Jørgen Garnæs i Claus Brøndgaard Madsen. "High-Resolution Structure-from-Motion for Quantitative Measurement of Leading-Edge Roughness". Energies 13, nr 15 (31.07.2020): 3916. http://dx.doi.org/10.3390/en13153916.
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Over time, erosion of the leading edge of wind turbine blades increases the leading-edge roughness (LER). This may reduce the aerodynamic performance of the blade and hence the annual energy production of the wind turbine. As early detection is key for cost-effective maintenance, inspection methods are needed to quantify the LER of the blade. The aim of this proof-of-principle study is to determine whether high-resolution Structure-from-Motion (SfM) has the sufficient resolution and accuracy for quantitative inspection of LER. SfM provides 3D reconstruction of an object geometry using overlapping images of the object acquired with an RGB camera. Using information of the camera positions and orientations, absolute scale of the reconstruction can be achieved. Combined with a UAV platform, SfM has the potential for remote blade inspections with a reduced downtime. The tip of a decommissioned blade with an artificially enhanced erosion was used for the measurements. For validation, replica molding was used to transfer areas-of-interest to the lab for reference measurements using confocal microscopy. The SfM reconstruction resulted in a spatial resolution of 1 mm as well as a sub-mm accuracy in both the RMS surface roughness and the size of topographic features. In conclusion, high-resolution SfM demonstrated a successful quantitative reconstruction of LER.
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SMAJIC, Selver, i Juraj JOVANOVIC. "INFLUENCE OF DIFFERENT MACHINING ON THE ROUGHNESS OF OAK WOOD". Series II: Forestry Wood Industry Agricultural Food Engineering 14(63), nr 1 (1.06.2021): 101–8. http://dx.doi.org/10.31926/but.fwiafe.2021.14.63.1.9.
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The paper presents research on the differences the in total roughness and the impact of parameters during different kinds of machining processes of oak samples. Oak wood samples were planed referring to a radial surface structure of wood. The planing machine was Weinig Unimat 500 and the planing head had two blades. The planing was conducted at a feed speed of 10, 15, 20, 25, and 30 m·min-1. The cutting depth of the machining grip was 1.00 mm and the rake angle of the tool blade was bio γ = 15°, at 6000°/min. The diameter of the cutting blade was Φ = 125 mm. Sanding was performed on a Viet Opera V contact sanding machine in combination heads with pre-planing knives and a roller with sanding belt. Roughness was measured along the grain in the latewood area of the annual growth using the electro mechanical profiler Mitutoyo SJ-500. The samples which were machined at a feed speed of 10 m·min-1 had the lowest roughness. The highest value of the roughness had samples which were machined at a feed speed of 30 m·min-1. After comparing roughness obtained during sanding and planing it was determined that the surface roughness obtained on a sanding machine approximately corresponds to the roughness obtained by planing at a feed speed of 20 and 25 m·min-1.
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Boyle, R. J. "Prediction of Surface Roughness and Incidence Effects on Turbine Performance". Journal of Turbomachinery 116, nr 4 (1.10.1994): 745–51. http://dx.doi.org/10.1115/1.2929468.
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The use of a Navier–Stokes analysis to predict the change in turbine efficiency resulting from changes in blade surface roughness or incidence flow angles is discussed. The results of a midspan Navier–Stokes analysis are combined with those from a quasi-three-dimensional flow analysis code to predict turbine performance. A quasi-three-dimensional flow analysis code was used to determine turbine performance over a range of incidence flow angles. This analysis was done for a number of incidence loss models. The change in loss due to changes in incidence flow computed from the Navier–Stokes analysis is compared with the results obtained using the empirical loss models. The Navier–Stokes analysis was also used to determine the effects of surface roughness using a mixing length turbulence model, which incorporated the roughness height. The validity of the approach used was verified by comparisons with experimental data for a turbine with both smooth and rough blades tested over a wide range of blade incidence flow angles.
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Zhang, Qinyi, Feng Liu, Dong Wu, Shikang Qu, Wei Liu i Zhangxiao Chen. "A Comprehensive Understanding of Knife Cutting: Effects of Hardness, Blade Angle and the Micro-Geometry of Blade Edge on the Cutting Performance". Materials 16, nr 15 (31.07.2023): 5375. http://dx.doi.org/10.3390/ma16155375.
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The cutting performance of steel blades is an eternal, attractive topic in the knife industry. It is a complicated process to cut up materials because it usually involves the contact mechanics of the material been cut, the geometry and roughness of the blade edge and the hardness and wear resistance of the blade steel. Therefore, a comprehensive analysis is required to evaluate the cutting performance of knife blades. In this study, such an analysis was conducted based on a quantitative model to describe the cutting depth of paper cards containing SiO2 particles by steel blades, and major contributing factors were summarized. The effect of the micro-geometries of blade edges was thoroughly discussed, and a geometry factor ξ for the micro-geometry of a blade edge was introduced into the model. The experimental results indicated that mechanical processing could produce a rough blade edge and a higher ξ value, accordingly. A similar effect was caused by the carbides in the martensitic steels for blades, and the ξ value was found to increase linearly with the volumetric fraction of the carbides. The extraordinary cutting behavior of the 3V blade implied that fine coherent carbides may result in an efficient improvement (40–50%) in the total cutting depth.
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Ortolani, Andrea, Alessio Castorrini i M. Sergio Campobasso. "Multi-scale Navier-Stokes analysis of geometrically resolved erosion of wind turbine blade leading edges". Journal of Physics: Conference Series 2265, nr 3 (1.05.2022): 032102. http://dx.doi.org/10.1088/1742-6596/2265/3/032102.
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Abstract A multi-scale computational fluid dynamics analysis of wind turbine blade leading edge erosion is presented. The test case is a large set of eroded blade sections. These are obtained by fitting the resolved eroded leading edge geometry of the outboard part of a multi-megawatt offshore wind turbine to the NACA633-618 airfoil. The erosion geometry measured by a blade laser scan is geometrically resolved in the aerodynamic simulations, whereas the aerodynamic effects of unresolved lower-amplitude scales are accounted for by using distributed surface roughness models. The simulations also account for the laminar-to-turbulent transition of the blade boundary layers with and without distributed roughness. An existing semi-empirical model and simulations of the nominal airfoil enable one to estimate the roughness level needed to trip leading edge boundary layer transition at the considered Reynolds number of 9 million. It is found that a) the mean roughness heights of the observed geometry perturbations are well above the critical roughness height, and b) consideration of either large or small erosion scales in isolation results in underestimating the airfoil performance impairment.
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Egorov, Sergey, Alexey Kapitanov, Dmitriy Loktev, Sergey Fedorov i Tatiana Egorova. "The Problems of Measuring Profile and Roughness of Turbine Blades". Applied Mechanics and Materials 876 (luty 2018): 110–16. http://dx.doi.org/10.4028/www.scientific.net/amm.876.110.
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The article presents a study of a turbine blade profile and roughness measurement processes - the task facing any manufacturer of this part. The blade is one of the most complex regarding parts manufacture because of its complex profile. This profile should be measured in several sections on the feather on all profile elements - the suction side, pressure surface, leading and trailing edge of a blade. If the blade has a shroud platform, its profile should be also measured (and possibly the gland packing profile). It is also necessary to measure the feather end and base of blade profile. Finally, a separate independent task is the blade tang profile measurement.
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Jafari, Kamyar, Mohammad Hassan Djavareshkian i Behzad Forouzi Feshalami. "The Effects of Different Roughness Configurations on Aerodynamic Performance of Wind Turbine Airfoil and Blade". International Journal of Renewable Energy Development 6, nr 3 (6.11.2017): 273. http://dx.doi.org/10.14710/ijred.6.3.273-281.
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In this research, viscous and turbulent flow is simulated numerically on an E387 airfoil as well as on a turbine blade. The main objective of this paper is to investigate various configurations of roughness to find a solution in order to mitigate roughness destructive impacts. Hence, the sand grain roughness is distributed uniformly along pressure side, suction side and both sides during the manufacturing process. Navier-Stokes equations are discretized by the finite volume method and are solved by SIMPLE algorithm. Results indicated that in contrast with previous studies, the roughness will be useful if it is applied on only pressure side of the airfoil. In this condition, the lift coefficient is increased to and 1.2% compare to the airfoil with rough and smooth sides, respectively. However, in 3-D simulation, the lift coefficient of the blade with pressure surface roughness is less than smooth blade, but still its destructive impacts are much less than of both surfaces roughness and suction surfaces roughness. Therefore, it can be deduced that in order to reveal the influence of roughness, the simulation must be accomplished in three dimensions.Article History: Received Jun 12th 2017; Received in revised form August 27th 2017; Accepted Oct 3rd 2017; Available onlineHow to Cite This Article: Jafari, K., Djavareshkian, M.H., Feshalami, B.H. (2017) The Effects of Different Roughness Configurations on Aerodynamic Performance of Wind Turbine Airfoil and Blade. International Journal of Renewable Energy Develeopment, 6(3), 273-281.https://doi.org/10.14710/ijred.6.3.273-281
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Huang, Yun, Ming Wei, GuiJian Xiao i Shuai Liu. "Belt grinding method considering outer profile and inner wall thickness". Journal of Physics: Conference Series 2252, nr 1 (1.04.2022): 012024. http://dx.doi.org/10.1088/1742-6596/2252/1/012024.
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Abstract Increasing thrust-to-weight ratio is the goal pursued by aero-engines. Aero-engine blades are the core components of aero-engines. In order to reduce the weight and improve the thrust-to-weight ratio, the cavity structure is gradually applied to aero-engine blades. The constraints of the outer contour and the inner wall thickness of the cavity structure blade make its trajectory planning difficult, which seriously affects its surface roughness and profile accuracy. In this study, proposes a titanium alloy blade surface machining method based on belt grinding, which is constrained by two dimensions of contour and wall thickness, and the process parameters of titanium alloy material specimens are studied. The obtained parameters are applied to the blade grinding process, the grinding trajectory is planned, and finally parameters of the blade are tested. The processing and testing results verify the effectiveness of the method in this paper.
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Huang, Yun, Ming Wei, GuiJian Xiao i Shuai Liu. "Belt grinding method considering outer profile and inner wall thickness". Journal of Physics: Conference Series 2252, nr 1 (1.04.2022): 012024. http://dx.doi.org/10.1088/1742-6596/2252/1/012024.
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Abstract Increasing thrust-to-weight ratio is the goal pursued by aero-engines. Aero-engine blades are the core components of aero-engines. In order to reduce the weight and improve the thrust-to-weight ratio, the cavity structure is gradually applied to aero-engine blades. The constraints of the outer contour and the inner wall thickness of the cavity structure blade make its trajectory planning difficult, which seriously affects its surface roughness and profile accuracy. In this study, proposes a titanium alloy blade surface machining method based on belt grinding, which is constrained by two dimensions of contour and wall thickness, and the process parameters of titanium alloy material specimens are studied. The obtained parameters are applied to the blade grinding process, the grinding trajectory is planned, and finally parameters of the blade are tested. The processing and testing results verify the effectiveness of the method in this paper.
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Hamed, A., W. Tabakoff i D. Singh. "Modeling of Compressor Performance Deterioration Due to Erosion". International Journal of Rotating Machinery 4, nr 4 (1998): 243–48. http://dx.doi.org/10.1155/s1023621x98000207.
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This paper presents the results of a simulation of compressor performance deterioration due to blade erosion. The simulation at both design and off-design conditions is based on a mean line row by row model, which incorporates the effects of blade roughness and tip clearance. The results indicate a pronounced effect of blade erosion on the compressor adiabatic efficiency and a lesser effect on the pressure ratio. The loss in performance is mainly caused by the increased blade surface roughness and was highest at 100% speed.
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Hasan, Muhammad Hasibul, i Shugata Ahmed. "Wear Resistance Performance of Conventional and Non-Conventional Wind Turbine Blades with TiN Nano-Coating". International Journal of Engineering Materials and Manufacture 2, nr 3 (14.09.2017): 37–48. http://dx.doi.org/10.26776/ijemm.02.03.2017.01.
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Efficiency and durability are critical issues that affect widely-adopted aerofoil-power generator as a sustainable source of electrical power. Even though high wind power density can be achieved; installing wind turbines in desert condition has difficulties including thermal variation, high turbulence and sand storms. Sand blasting on turbine blade surface at high velocities causes erosion resulting turbine efficiency drop. Damage-induced erosion phenomena and aeroelastic performance of the blades needed to be investigated. Suitable coating may prevent erosion to a great extent. A numerical investigation of erosion on NACA 4412 wind turbine blade has been performed using commercial computational fluid dynamics software ANSYS FLUENT 14.5 release. Discrete phase model (DPM) has been used for modelling multi-phase flow of air and sand particles over the turbine blade. Governing equations have been solved by finite volume method (FVM). Conventional 30-70% glass fibre resin and non-conventional jute fibre composite have been used as turbine blade material. Sand particles of diameter have been injected from 20, 30, 45, 60 and 90 degree angles at 500C temperature. Erosion rate, wall shear stress and strain rate have been calculated for different wind velocities and impingement angles. Simulation results for higher velocities deviate from the results observed at lower wind velocities. In simulation, erosion rate is highest for impingement angle at low wind velocities, which has been validated by experiment with a mean absolute error (MAE) of 5.56%. Erosion rate and wall shear stress are higher on jute composite fibre than glass fibre resin. Developed shear stress on wind turbine blade surface is highest for impingement angle at all velocities. On the other hand, exerted pressure on turbine blade surface is found highest for 9 angle of attack. Experimental results, with or without Titanium nitride(TiN) nano-coating, also revealed that surface roughness augments with increasing impingement angles. Nano-coating (TiN) by RF sputtering technique reduced the surface roughness significantly as oppose to uncoated samples. Highest roughness has been observed on uncoated blade surface collided with 0.3-0.69 mm diameter brown aluminium oxide particles.
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Bishtawi, Basel Al, Gianfranco Scribano i Manh-Vu Tran. "Numerical Study of Blade Roughness Effect on Cavitation in Centrifugal Pumps". Journal of Physics: Conference Series 2051, nr 1 (1.10.2021): 012047. http://dx.doi.org/10.1088/1742-6596/2051/1/012047.
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Abstract Cavitation is classified as an undesirable complex multiphase phenomenon due to its negative effects on the structural and flow behaviours of hydraulic machineries, specifically centrifugal pumps. Typically, the pump’s cavitation performance tends to vary due to a multitude of factors, one of which is the impeller blade roughness. In this study, a numerical analysis is conducted, using ANSYS Fluent 20.1, to evaluate the relationship between the impeller blade roughness and the cavitation performance of an ISO 80-50-250 centrifugal pump operating at different pressures and flow rates. The operating conditions include net positive suction head (NPSH) values set at 20, 7.25, 5.71, 2.58, 1.1 m along with outlet mass flow rates of 40, 50, 60 m3/h while the blade roughness height value is changed to 1, 20, 80 μm. The SST k-ω turbulence model, along with the Zwart-Gerber-Belamri cavitation model is used. The results showed that the pressure head increased by approximately 1.64%, 1.55%, and 1.90% at flow rates of 40, 50, and 60 m3/h when the roughness height was increased from 0 μm to 80 μm. However, the increase in roughness improved cavitation inception simultaneously. Meanwhile, the blade suction-side witnessed a delay in cavitation formation, as it shifted downstream towards the trailing edge from its initial point of formation at the blade passage.
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Hummel, Frank, Michael Lötzerich, Pasquale Cardamone i Leonhard Fottner. "Surface Roughness Effects on Turbine Blade Aerodynamics". Journal of Turbomachinery 127, nr 3 (2005): 453. http://dx.doi.org/10.1115/1.1860377.
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Nosov, N. V., N. P. Kostin i R. V. Ladyagin. "Estimation of texture parameters for the precision surfaces using the quasioptimal correlation algorithms". Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta, nr 1 (2021): 24–31. http://dx.doi.org/10.18323/2073-5073-2021-1-24-31.
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The authors considered a new method of texture analysis of machined precision surfaces based on using computer optics and the autocorrelation method of processing the images of micro-relief textures under the study. This method is based on a probabilistic comparative evaluation of the unknown texture of the micro-relief under the investigation with the available textures of reference micro-patterns, in which microrelief parameters are determined. The paper proposes an approach to identify the profile surface roughness of a gas turbine engine (GTE) blade after vibro-contact polishing according to the parameters of correlation surface texture. The authors studied the surface micro-geometry of the blade back and pressure side using the optoelectronic complex based on the calculation of the average amplitude of the variable component of an autocorrelation function resulting from computer processing of a surface video image. The application of the electrooptic method for evaluating the surface texture of compressor and turbine blades allows building the surface roughness fields and more deeply analyzing the technology of final processing of the GTE blade feather profile. The relevance and novelty of the study lie in the promising technique to evaluate the surface quality parameters using the electrooptic method. A special feature of this method is the measurement of surface area roughness, while the stylus methods measure the roughness of the surface profile. An important advantage of the proposed method is its application to measure the roughness parameters of a curved surface by a non-contact method, which is advanced since there are surfaces of parts that do not imply being scratched with a diamond needle.
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Livya, E., R. Abishaveni, M. D. Ashika Deepthi, P. Ranjitha i S. Nadaraja Pillai. "Analyzing the aerodynamic characteristics of eroded wind turbine blades". IOP Conference Series: Earth and Environmental Science 1161, nr 1 (1.04.2023): 012015. http://dx.doi.org/10.1088/1755-1315/1161/1/012015.
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Abstract The study investigates the influence of erosion over the leading edge of S809 series airfoil and its impact on the aerodynamic performance of wind turbine blades. The research work determines how erosion affects the performance of wind turbine blades at an angle of attack varying from 0° to 45° for the fixed Reynolds number of 2.1 x 105. To analyse the flow characteristics, the average pressure acting around the surface of the airfoil is scanned with the aid of 20 pressure taps. The time series pressure of 10,000 samples at each point has been collected. The roughness is introduced at the leading edge of the airfoil and measures 0.1% of the total chord at the top and bottom surface, respectively. Six different intensities of roughness are introduced and tested. The base airfoil, as well as roughed surface airfoil, is compared and the results are discussed. The aerodynamic parameters like lift, drag, and pressure coefficients are included. The estimated data suggests the erosion that occurs on the wind turbine blade surface alters the flow pattern and the aerodynamic properties of the wind turbine blades. Collectively, the experiment on analysing the eroded surface possibly taking place over the wind turbine blade surface affects the lift parameter with a considerable increment in drag. However, the roughness allows the airflow to remain fixed with the airfoil surface, favouring the concept of extending the stall.
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Vimalakanthan, Kisorthman, Harald van der Mijle Meijer, Iana Bakhmet i Gerard Schepers. "Computational fluid dynamics (CFD) modeling of actual eroded wind turbine blades". Wind Energy Science 8, nr 1 (4.01.2023): 41–69. http://dx.doi.org/10.5194/wes-8-41-2023.
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Abstract. Leading edge erosion (LEE) is one of the most critical degradation mechanisms that occur with wind turbine blades (WTBs), generally starting from the tip section of the blade. A detailed understanding of the LEE process and the impact on aerodynamic performance due to the damaged leading edge (LE) is required to select the most appropriate leading edge protection (LEP) system and optimize blade maintenance. Providing accurate modeling tools is therefore essential. This paper presents a two-part study investigating computational fluid dynamics (CFD) modeling approaches for different orders of magnitudes in erosion damage. The first part details the flow transition modeling for eroded surfaces with roughness on the order of 0.1–0.2 mm, while the second part focuses on a novel study modeling high-resolution scanned LE surfaces from an actual blade with LEE damage on the order of 10–20 mm (approx. 1 % chord); 2D and 3D surface-resolved Reynolds-averaged Navier–Stokes (RANS) CFD models have been applied to investigate wind turbine blade sections in the Reynolds number (Re) range of 3–6 million. From the first part, the calibrated CFD model for modeling flow transition accounting for roughness shows good agreement of the aerodynamic forces for airfoils with leading-edge roughness heights on the order of 140–200 µm while showing poor agreement for smaller roughness heights on the order of 100 µm. Results from the second part of the study indicate that up to a 3.3 % reduction in annual energy production (AEP) can be expected when the LE shape is degraded by 0.8 % of the chord, based on the NREL5MW turbine. The results also suggest that under fully turbulent conditions, the degree of eroded LE shapes studied in this work show the minimal effect on the aerodynamic performances, which results in a negligible difference to AEP.
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Vdovin, R. A. "Investigation of Uniformity of Allowance along Airfoil of GTE Turbine Blade". MATEC Web of Conferences 329 (2020): 03054. http://dx.doi.org/10.1051/matecconf/202032903054.
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This paper shows the results of a study of the uniformity of the allowance along the airfoil in the turbine blades workpieces. It is found that in the existing industry, there is a defect associated with a lack of allowance along the airfoil (from the blade back and pressure side) for the polishing operation in order to give the required cleanliness and roughness of the surface layer. By measuring the wall thickness of the blade airfoils, it is concluded that by mechanically modifying the technological bases on the blade, it is possible to select the optimal position of the workpiece in the template instrument, at which the allowance along the airfoil is relatively uniform, and the dimensions of the blade wall thickness will be within the specified tolerance.
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Jarolmasjed, Seyedamin, Behnam Davoodi i Babak Pourebrahim Alamdari. "Influence of milling toolpaths in machining of the turbine blade". Aircraft Engineering and Aerospace Technology 91, nr 10 (4.11.2019): 1327–39. http://dx.doi.org/10.1108/aeat-12-2018-0316.
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Purpose The purpose of this paper is to machine the pressure surface of the turbine blade made of A286 iron-based superalloy by using four directions of raster strategy, including horizontal upward, horizontal downward, vertical upward and vertical downward, to achieve appropriate surface roughness and to investigate the tool wear in each strategy. Design/methodology/approach In this study, all cutting tests were performed by DAHLIH-MCV 1020 BA vertical 3-axis machining center with ball nose end mill. After milling by each strategy, according to the surface slope, the surface was divided into 27 meshes, and roughness of surface was studied and compared. Roughness measuring after machining was implemented by using portable Mahr ps1 roughness tester, and surface texture was photographed by CCD 100× optical zoom camera. Also, to measure tool flank wear in each strategy as an indication of tool life, the surface of workpiece was divided into four equal areas. The wear of the inserts was measured by ARCS vertical non-contact measuring system at the end of each area. Findings The results indicate that cutting directions and toolpath strategies have significant influence on tool wear and surface roughness in machining processes and that they can be taken into consideration individually as determinative parameters. In this case, the most uniform surface texture and the lowest surface roughness are obtained by using horizontal downward direction; in addition, abrasion is a dominant tool wear mechanism in all experiments, and tool wear in the horizontal downward is lower than other strategies. Practical implications Machining of turbine blades or other airfoil-shaped workpieces is quite common in manufacturing aerospace and aircraft products. The results of this research contribute to increasing quality of machined surface and tool life in machining of turbine blade. Originality/value This work proves the significance of milling strategies in machining of the turbine blade made of A286 superalloy and, consequently, exhibits the proper strategy in terms of surface roughness and tool life. Also, this work explains and elaborates the behavior of A286 superalloy in machining processes, which has not been studied much in recent research works.
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Shi, Yameng, Baoqin Wen, Liqiao Li, Tao Wang, Yang Li, Sixue Ren i Jingbin Li. "Analysis of Wear Characteristics of Blade Materials and Glycyrrhiza uralensis". Transactions of the ASABE 64, nr 4 (2021): 1259–68. http://dx.doi.org/10.13031/trans.14442.
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HighlightsThe thermal reaction between Glycyrrhiza uralensis and metal was analyzed via thermogravimetry.The wear characteristics of three common blade metals were studied under laboratory conditions.The wear mechanisms on the blades by different parts of Glycyrrhiza uralensis were analyzed.Thermal oxidation and element transfer occurred during the wear of Glycyrrhiza uralensis and metals.Abstract. To investigate the wear of metal blades when kneading and crushing total mixed ration (TMR) forage grass, the chemical composition of licorice (Glycyrrhiza uralensis) was determined using hydrochloric acid hydrolysis, titration, and Kjeldahl nitrogen determination, and the thermal stability of G. uralensis was analyzed with thermogravimetry (TG). Blades made of spring steel (65Mn), mold steel (Cr12MoV), and tool steel (9CrSi) were selected for the wear tests. The wear mechanisms of the cork and wood layers of G. uralensis on blades were explored via reciprocating friction. The elemental content and worn surface morphology of the blades were analyzed using inductively coupled plasma atomic emission spectrometry (ICP-AES), three-dimensional morphology, scanning electron microscopy, and X-ray energy spectrum analysis. Results showed that the wear on the blades was mainly abrasive, fatigue, and adhesive wear. Comparison of the wear of the G. uralensis cork and wood layers with that of the three blade types revealed that the coefficient of friction was smallest for the 65Mn blades, at 0.20 and 0.75, respectively, for the cork and wood layers. The combination of pyrolysis of G. uralensis with a change in the atomic content on the wear surfaces of the blades indicated that the wear process of the blades was accompanied by thermal oxidation. Damage to the blades by the G. uralensis wood layer was more serious than damage by the cork layer. The surface roughness and the depth of the wear scars for the G. uralensis wood layer on 65Mn blades were 0.085 µm and 0.427 µm, respectively, which were lower than the wear parameters for the Cr12MoV and 9CrSi blades under the same conditions. Therefore, 65Mn blades have good wear resistance and plastic resistance under the same wear condition. This study provides a reference for blade selection for cutting of TMR forage materials. Keywords: Blade, Glycyrrhiza uralensis, Surface roughness, Wear resistance, Weightlessness rate.
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Kind, R. J., P. J. Serjak i M. W. P. Abbott. "Measurements and Prediction of the Effects of Surface Roughness on Profile Losses and Deviation in a Turbine Cascade". Journal of Turbomachinery 120, nr 1 (1.01.1998): 20–27. http://dx.doi.org/10.1115/1.2841383.
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Measurements of pressure distributions, profile losses, and flow deviation were carried out on a planar turbine cascade in incompressible flow to assess the effects of partial roughness coverage of the blade surfaces. Spanwise-oriented bands of roughness were placed at various locations on the suction and pressure surfaces of the blades. Roughness height, spacing between roughness elements, and band width were varied. A computational method based on the inviscid/viscous interaction approach was also developed; its predictions were in good agreement with the experimental results. This indicates that good predictions can be expected for a variety of cascade and roughness configurations from any two-dimensional analysis that couples an inviscid method with a suitable rough surface boundary-layer analysis. The work also suggests that incorporation of the rough wall skin-friction law into a three-dimensional Navier–Stokes code would enable good predictions of roughness effects in three-dimensional situations. Roughness was found to have little effect on static pressure distribution around the blades and on deviation angle, provided that it does not precipitate substantial flow separation. Roughness on the suction surface can cause large increases in profile losses; roughness height and location of the leading edge of the roughness band are particularly important. Loss increments due to pressure-surface roughness are much smaller than those due to similar roughness on the suction surface.
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Moshizi, S. A., M. H. Nakhaei, M. J. Kermani i A. Madadi. "Development of a Numerical Based Correlation for Performance Losses due to Surface Roughness in Axial Turbines". Journal of Mechanics 30, nr 6 (13.03.2014): 631–42. http://dx.doi.org/10.1017/jmech.2014.10.
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AbstractIn the present work, a recently developed in-house 2D CFD code is used to study the effect of gas turbine stator blade roughness on various performance parameters of a two-dimensional blade cascade. The 2D CFD model is based on a high resolution flux difference splitting scheme of Roe (1981). The Reynolds Averaged Navier-Stokes (RANS) equations are closed using the zero-equation turbulence model of Baldwin-Lomax (1978) and two-equation Shear Stress Transport (SST) turbulence model. For the smooth blade, results are compared with experimental data to validate the model. Finally, a correlation between roughness Reynolds number and loss coefficient for both turbulence models is presented and tested for three other roughness heights. The results of 2D turbine blade cascades can be used for one-dimensional models such as mean line analysis or quasi-three-dimensional models e.g. streamline curvature method.
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Sazonov, M. B., i L. V. Solovatskaya. "Influence of the stressed state of the surface layer on the endurance of gas turbine engine compressor blades". VESTNIK of Samara University. Aerospace and Mechanical Engineering 18, nr 1 (16.04.2019): 109–17. http://dx.doi.org/10.18287/2541-7533-2019-18-1-109-117.
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Different types of final strengthening treatment of gas turbine engine (GTD) compressor blades are considered. The influence of each type of treatment on the formation of roughness of the surface with favorable microrelief, as well as on the level and depth of distribution of residual compressive stresses in the compressor blade airfoil is analyzed. The causes of blade fatigue failure are described and methods of controlling this kind of failure are presented. The results of testing special specimens made of VT9 titanic alloy are presented to establish the influence of final strengthening treatment modes on the compressor blade resistance to fatigue stress. The results of testing residual stress distribution along the thickness of compressor blade airfoil are presented. A method of improving dynamic strengthening of specimens due to the protection of compressor blade edges is discussed. The results of semi-graphical analysis of the stressed state of low-pressure and medium-pressure compressor blades made of VT9 alloy are presented. They take into account residual stresses, as well as operating load stresses in the process of operation. We show that it is possible to increase the limit of the blade endurance due to the optimization of residual stress diagrams by improving the final strengthening technology with the use of dust blasting.
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Khuengpukheiw, Ronnarit, Charnnarong Saikaew i Anurat Wisitsoraat. "Wear resistance of HVOF sprayed NiSiCrFeB, WC-Co/NiSiCrFeB, WC-Co, and WC-Cr3C2-Ni rice harvesting blades". Materials Testing 63, nr 1 (1.01.2021): 62–72. http://dx.doi.org/10.1515/mt-2020-0009.
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Abstract In this work, NiSiCrFeB, WC-Co/NiSiCrFeB, WC-Co, and WC-Cr3C2-Ni coatings were sprayed on rice harvesting blade surfaces using a high velocity oxygen fuel (HVOF) process. Each of the rice harvesting blades was sprayed with one of four coating materials using different spraying durations. The effects of coating materials and spraying durations on the average values of coated blade volume loss, hardness and surface roughness (Ra) were studied through real rice-harvesting field tests. Analysis of variance (ANOVA) and a multiple comparison approach with Tukey’s test were used in order to conduct a comparative performance analysis of the coating materials of rice harvesting blades. The experimental results indicated that the NiSiCrFeB coating exhibited the highest volume loss compared with all others. In addition, the WC-Co-coated blade had significantly greater hardness than those coated with NiSiCrFeB, WC-Co/NiSiCrFeB, or WC-Cr3C2-Ni. The rice harvesting blade coated with either WC-Co/NiSiCrFeB, WC-Co, or WC-Cr3C2-Ni using the shortest spraying duration was recommended for installation in rice harvesting machines.
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Kelly, Jack, Richard Willden i Christopher Vogel. "Parameterising the Impact of Roughness Evolution on Wind Turbine Performance". Wind 2, nr 2 (20.06.2022): 415–28. http://dx.doi.org/10.3390/wind2020022.
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This paper presents a study investigating the effects of surface roughness on airfoil performance and its consequences for wind turbine energy yield. This study examined 51 sets of experimental data across 16 airfoils to identify trends in roughened airfoil performance. The trends are used to formulate a novel ‘roughness evolution parameter’ that can be applied to airfoils with no roughened data available to predict the impact of roughness on performance. Blade element momentum theory is used to model the performance of the DTU 10 MW reference wind turbine, with uniformly roughened blades emulated using the roughness evolution parameter. An annual energy production loss between 0.6–9.6% is found for the DTU 10 MW turbine when considering a plausible range of values for the roughness evolution parameter derived from the experimental data. A framework has been developed to evaluate how the roughness evolution parameter changes over time, informed by observed changes in wind farm performance from previous studies.
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Tsai, Ming Yi. "Blade Diamond Disk for Conditioning CMP Polishing Pad". Advanced Materials Research 97-101 (marzec 2010): 3–6. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.3.
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A diamond conditioner or dresser is needed to regenerate the asperity structure of the pad and recover its designed ability in chemical mechanical polishing (CMP) process. In this paper a new design of diamond conditioner is made by shaping a sintered matrix of polycrystalline diamond (PCD) to form teethed blades. These blades are arranged and embedded in epoxy resin to make a designed penetration angle, called the blade diamond disk. The dressing characteristics of pad surface textures are studied by comparison with conventional diamond conditioner. It is found that the height variation of the diamond tip of blade diamond disk is significantly smaller than the conventional diamond disk. The dressing rate of blade diamond disk is lower than that of the conventional diamond disk, and hence the pad life is prolonged. As a result, reduction of the cost CMP is expected. In addition the pad surface roughness Ra of about 3.79μm is less than Ra of about 4.15μm obtained after dressing using a conventional diamond disk.
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Gbadebo, Semiu A., Tom P. Hynes i Nicholas A. Cumpsty. "Influence of Surface Roughness on Three-Dimensional Separation in Axial Compressors". Journal of Turbomachinery 126, nr 4 (1.10.2004): 455–63. http://dx.doi.org/10.1115/1.1791281.
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Surface roughness on a stator blade was found to have a major effect on the three-dimensional (3D) separation at the hub of a single-stage low-speed axial compressor. The change in the separation with roughness worsened performance of the stage. A preliminary study was carried out to ascertain which part of the stator suction surface and at what operating condition the flow is most sensitive to roughness. The results show that stage performance is extremely sensitive to surface roughness around the leading edge and peak-suction regions, particularly for flow rates corresponding to design and lower values. Surface flow visualization and exit loss measurements show that the size of the separation, in terms of spanwise and chordwise extent, is increased with roughness present. Roughness produced the large 3D separation at design flow coefficient that is found for smooth blades nearer to stall. A simple model to simulate the effect of roughness was developed and, when included in a 3D Navier–Stokes calculation method, was shown to give good qualitative agreement with measurements.
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Guo, Jian, Yaoyao Shi, Zhen Chen, Tao Yu, Pan Zhao i Bijan Shirinzadeh. "Optimal Parameter Selection in Robotic Belt Polishing for Aeroengine Blade Based on GRA-RSM Method". Symmetry 11, nr 12 (17.12.2019): 1526. http://dx.doi.org/10.3390/sym11121526.
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Due to its flexibility and versatility, robotic belt polishing is one of the most effective processing methods to improve the surface quality of aeroengine blades. Since belt polishing of blades is a material removal process aimed at reducing surface roughness, it is difficult to achieve both minimum surface roughness and maximum material removal rates. In order to solve this problem, this paper proposes an optimization method combining grey correlation analysis (GRA), the Taguchi method, and the response surface method (RSM) for the multiobjective optimization of the process parameters of Ti–6Al–4V aeroengine blade polishing. Meanwhile, the problem of the influence of asymmetry on the polishing process parameters vis-a-vis the optimization goal was solved. Experiments of robotic belt polishing for aeroengine blades were carried out. Based on the results of the principal component analysis, the grey relational grade was established to turn multiobjective optimization into single-objective optimization. A quadratic regression model of Grey correlation grade was developed, and an optimal parameter combination was obtained by the RSM. Finally, verification experiments were performed, and the combination of optimal parameters was obtained as follows: feed rate of 232.09 mm/min, compression amount of 0.08 mm, and belt line speed of 16 m/s, which reduced surface roughness by 6.29% and increased the material removal rate by 16.11%. Comparing the results of GRA-RSM and GRA, the Grey correlation grade increased by 10.96%. In other words, the goal of simultaneously reducing the surface roughness and improving the material removal rate was achieved in robotic belt polishing for aeroengine blades.
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Pinkowski, Grzegorz, Waldemar Szymański, Magdalena Piernik i Andrzej Krauss. "Medium-density fibreboard milling using selected technological parameters". BioResources 16, nr 1 (24.11.2020): 558–71. http://dx.doi.org/10.15376/biores.16.1.558-571.
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The aim of this study was to investigate the effect of blade type and sharpness angle on blade wear, cutting power, and surface roughness. The study was conducted on medium-density fibreboard (MDF) panels. Two blade types were analyzed (high-speed steel and cemented carbides) along with three variants of sharpness angles (40°, 45°, and 55°). Machining operations were performed on a spindle moulder at a feed rate of 6.3 m/min and rotational speed of 4500 min-1. The blade wear criterion was adopted as the loss of cutter surface area measured on the rake face. Roughness was determined using the Ra parameter, which was measured at three points on the cross-section of the MDF panel. A new, multifaceted approach to the study of cutting a narrow surface of the MDF board was used, thanks to which the interaction of such parameters as blade wear, cutting power, and machining quality as well as the type of material of the knives and their angular parameters were determined. An increase in blade wear and cutting power was recorded with an increase in cutting path, while roughness at the MDF panel cross-section varied. The cemented carbides cutter with the 45° angle may be proposed as optimal, because it showed a relatively low wear and cutting power while providing good quality of the milled surface.
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van Rooij, R. P. J. O. M., i W. A. Timmer. "Roughness Sensitivity Considerations for Thick Rotor Blade Airfoils". Journal of Solar Energy Engineering 125, nr 4 (1.11.2003): 468–78. http://dx.doi.org/10.1115/1.1624614.
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In modern wind turbine blades, airfoils of more than 25% thickness can be found at mid-span and inboard locations. At mid-span, aerodynamic requirements dominate, demanding a high lift-to-drag ratio, moderate to high lift and low roughness sensitivity. Towards the root, structural requirements become more important. In this paper, the performance for the airfoil series DU FFA, S8xx, AH, Risø and NACA are reviewed. For the 25% and 30% thick airfoils, the best performing airfoils can be recognized by a restricted upper-surface thickness and an S-shaped lower surface for aft-loading. Differences in performance of the DU 91-W2-250 (25%), S814 (24%) and Risø-A1-24 (24%) airfoils are small. For a 30% thickness, the DU 97-W-300 meets the requirements best. Reduction of roughness sensitivity can be achieved both by proper design and by application of vortex generators on the upper surface of the airfoil. Maximum lift and lift-to-drag ratio are, in general, enhanced for the rough configuration when vortex generators are used. At inboard locations, 2-D wind tunnel tests do not represent the performance characteristics well because the influence of rotation is not included. The RFOIL code is believed to be capable of approximating the rotational effect. Results from this code indicate that rotational effects dramatically reduce roughness sensitivity effects at inboard locations. In particular, the change in lift characteristics in the case of leading edge roughness for the 35% and 40% thick DU airfoils, DU 00-W-350 and DU 00-W-401, respectively, is remarkable. As a result of the strong reduction of roughness sensitivity, the design for inboard airfoils can primarily focus on high lift and structural demands.