scholarly journals Evaluation of Anti-Icing Performance for an NACA0012 Airfoil with an Asymmetric Heating Surface

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 294
Author(s):  
Koji Fukudome ◽  
Yuki Tomita ◽  
Sho Uranai ◽  
Hiroya Mamori ◽  
Makoto Yamamoto
Keyword(s):  
Prediction Method ◽  
Heating Surface ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Suction Surface ◽  
Ice Volume ◽  
Naca0012 Airfoil ◽  
Static Heating ◽  
Flow Drag ◽  
Asymmetric Heating

Heating devices on airfoil surfaces are widely used as an anti-icing technology. This study investigated the aerodynamic performance with a static heating surface based on the modified extended Messinger model. The predicted ice shape was validated through a comparison with the experimental results for HAARP-II. A reasonable agreement was found for both the icing area and the ice mass on the suction surface. Then, the prediction method was adopted for an NACA0012 airfoil at an attack angle of 4.0∘ under a glaze ice condition. An asymmetric heating area was imposed on the suction and pressure surfaces considering a temperature of 10∘C near the leading edge. As a result of heating, the round ice formation when was no longer observed, and the formed ice volume decreased. However, bump-shaped pieces of ice were formed downstream of the heater owing to runback water; these bump-shaped pieces of ice formed on the suction surface significantly increased the flow drag and reduced the lift. The results indicated that extending the heating area on the suction surface can improve the aerodynamic performance. Consequently, the overall aerodynamic performance is deteriorated by adding static heating compared to the case without heating.

scholarly journals Numerical Simulation of the Anti-Icing Performance of Electric Heaters for Icing on the NACA 0012 Airfoil

Aerospace ◽  
2020 ◽  
Vol 7 (9) ◽  
pp. 123
Author(s):  
Sho Uranai ◽  
Koji Fukudome ◽  
Hiroya Mamori ◽  
Naoya Fukushima ◽  
Makoto Yamamoto
Keyword(s):  
Numerical Simulation ◽  
Lift Coefficient ◽  
Heating Surface ◽  
Leading Edge ◽  
Simulation Method ◽  
Chord Length ◽  
Ice Accretion ◽  
Suction Surface ◽  
Edge Surface ◽  
Naca 0012

Ice accretion is a phenomenon whereby super-cooled water droplets impinge and accrete on wall surfaces. It is well known that the icing may cause severe accidents via the deformation of airfoil shape and the shedding of the growing adhered ice. To prevent ice accretion, electro-thermal heaters have recently been implemented as a de- and anti-icing device for aircraft wings. In this study, an icing simulation method for a two-dimensional airfoil with a heating surface was developed by modifying the extended Messinger model. The main modification is the computation of heat transfer from the airfoil wall and the run-back water temperature achieved by the heater. A numerical simulation is conducted based on an Euler–Lagrange method: a flow field around the airfoil is computed by an Eulerian method and droplet trajectories are computed by a Lagrangian method. The wall temperature distribution was validated by experiment. The results of the numerical and practical experiments were in reasonable agreement. The ice shape and aerodynamic performance of a NACA 0012 airfoil with a heater on the leading-edge surface were computed. The heating area changed from 1% to 10% of the chord length with a four-degree angle of attack. The simulation results reveal that the lift coefficient varies significantly with the heating area: when the heating area was 1.0% of the chord length, the lift coefficient was improved by up to 15%, owing to the flow separation instigated by the ice edge; increasing the heating area, the lift coefficient deteriorated, because the suction peak on the suction surface was attenuated by the ice formed. When the heating area exceeded 4.0% of the chord length, the lift coefficient recovered by up to 4%, because the large ice near the heater vanished. In contrast, the drag coefficient gradually decreased as the heating area increased. The present simulation method using the modified extended Messinger model is more suitable for de-icing simulations of both rime and glaze ice conditions, because it reproduces the thin ice layer formed behind the heater due to the runback phenomenon.

Proposal of Novel Icing Simulation Using a Hybrid Grid- and Particle-Based Method

2020 ◽  
Vol 36 (5) ◽  
pp. 699-706
Author(s):  
D. Toba ◽  
K. Fukudome ◽  
H. Mamori ◽  
N. Fukushima ◽  
M. Yamamoto
Keyword(s):  
Surface Roughness ◽  
Numerical Simulations ◽  
Computing Time ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Air Voids ◽  
Naca0012 Airfoil ◽  
Hybrid Grid ◽  
Short Computing Time ◽  
Grid Based

ABSTRACTIcing on aircraft can drastically reduce aerodynamic performance and lead to serious accidents. Therefore, prediction of the accreted ice shape and area and its effects on aerodynamic performance is crucial during the design phase of an aircraft. However, numerical simulations based on conventional grid-based methods such as the finite volume method cannot accurately reproduce the complex ice shapes, which involve horn growth, feather growth, air voids, and severe surface roughness. In the present study, instead of the grid-based method, a hybrid grid- and particle-based method was newly proposed and applied to the icing problem on a NACA0012 airfoil. The explicit moving particle semi-implicit method was employed as the particle-based method due to its short computing time. The numerical simulations effectively reproduced feather-shaped ice, air voids, and surface roughness. Finally, by computing the flow around the iced airfoil, it was confirmed that flow separation around the leading edge occurred due to the ice layer, which resulted in a thicker boundary layer and wake and an increase in the drag coefficient of approximately 70% after a residence time of only 60 seconds.

scholarly journals The Effect of Adding Roughness and Thickness to a Transonic Axial Compressor Rotor

1995 ◽  
Vol 117 (4) ◽  
pp. 491-505 ◽  
Author(s):  
K. L. Suder ◽  
R. V. Chima ◽  
A. J. Strazisar ◽  
W. B. Roberts
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Axial Compressor ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Blade Surface ◽  
Suction Surface ◽  
Compressor Rotor ◽  
Performance Deterioration ◽  
Design Speed

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.

Analysing and Optimizing the Aerodynamic Performance of Wind Turbine Blades Using Injected-Air Jets at Variable Frequency and Amplitude for Flow Control

2005 ◽  
Vol 29 (4) ◽  
pp. 331-339 ◽  
Author(s):  
Liu Hong ◽  
Huo Fupeng ◽  
Chen Zuoyi
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Suction Surface ◽  
Air Jet

Optimum aerodynamic performance of a wind turbine blade demands that the angle of attack of the relative wind on the blade remains at its optimum value. For turbines operating at constant speed, a change in wind speed causes the angle of attack to change immediately and the aerodynamic performance to decrease. Even with variable speed rotors, intrinsic time delays and inertia have similar effects. Improving the efficiency of wind turbines under variable operating conditions is one of the most important areas of research in wind power technology. This paper presents findings of an experimental study in which an oscillating air jet located at the leading edge of the suction surface of an aerofoil was used to improve the aerodynamic performance. The mean air-mass flowing through the jet during each sinusoidal period of oscillation equalled zero; i.e. the jet both blew and sucked. Experiments investigated the effects of the frequency, momentum and location of the jet stream, and the profile of the turbine blade. The study shows significant increase in the lift coefficient, especially in the stall region, under certain conditions. These findings may have important implications for wind turbine technology.

The synergistic effect between compound lean and aspiration on aerodynamic performance in compressor cascades

2017 ◽  
Vol 232 (16) ◽  
pp. 3034-3048
Author(s):  
Jun Ding ◽  
Shaowen Chen ◽  
Le Cai ◽  
Songtao Wang ◽  
Zhongqi Wang ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Pressure Gradient ◽  
Leading Edge ◽  
Adverse Pressure Gradient ◽  
Aerodynamic Performance ◽  
Suction Surface ◽  
Reciprocal Effect ◽  
Blade Passage ◽  
Streamwise Location ◽  
Lean Angle

In this paper, the synergistic effect between compound lean and aspiration on the aerodynamic performance of compressor cascades is discussed. Preliminary experimental data verify the accuracy of the computational fluid dynamics method adopted, and a thorough study on reciprocal effect among lean angle, aspirated flow fraction and aspiration streamwise location is conducted. The calculations show that, due to the shorter streamwise length of the re-grown boundary layer against adverse pressure gradient, the aspiration location located farther downstream from the leading edge can minimize the loss of the blade passage flow. With the application of blade lean, which is similar to the flow control mechanism in the unaspirated cascades, an increase in pressure at the suction surface corner is used to migrate the low momentum fluid from the corners towards the midspan of the suction surface. Meanwhile, the reduced aspirated flow velocity and the improved favorable pressure gradient in the lean anterior plenum can reduce the entropy rise through the plenum. Simultaneously, the suction power required in the blade passage flow is reduced with blade lean, while the suction power for the aspirated flow through the plenum shows the opposite trend.

Numerical Simulation of Influence with Surface Contamination on Aerodynamic Performance of Dedicated Wind Turbine Airfoil

2013 ◽  
Vol 724-725 ◽  
pp. 572-575
Author(s):  
Pan Wu ◽  
Chun Li ◽  
Zhi Min Li
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Surface Contamination ◽  
Suction Surface ◽  
Airfoil Surface ◽  
Pressure Surface ◽  
Sst Turbulence Model ◽  
Wind Turbine Airfoil

A Numerical simulation on the influence of airfoil surface contamination on the aerodynamic performance of wind turbines was performed. It chose the dedicated wind turbine airfoil as the research object. The k-ω Shear Stress Transmission (SST) turbulence model was selected for CFD calculation. The roughness height which arranged evenly on the airfoil was changed from 0.03mm to 2.0mm to obtain the sensitive roughness. The airfoil was divided into 18 sections for analyzing the effect on the lift & the drag coefficient, due to various locations of sensitive roughness. By comparing the result computed by XFOIL and CFD calculation, it can be known this airfoils sensitive locations in suction surface and pressure surface. The sensitive locations in suction surface were 53% and 92% from the chord line towards the leading edge, while 44% and 88% in pressure surface. The sensitive roughness in sensitive locations delayed the location of the transition point.

Selection of a leading edge noise prediction method for PNoise

2018 ◽  
pp. 214-223
Author(s):  
AM Faria ◽  
MM Pimenta ◽  
JY Saab Jr. ◽  
S Rodriguez
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Prediction Method ◽  
Leading Edge ◽  
Wind Farms ◽  
Broadband Noise ◽  
Turbulence Energy ◽  
Noise Prediction ◽  
Migration Routes ◽  
Turbulent Inflow

Wind energy expansion is worldwide followed by various limitations, i.e. land availability, the NIMBY (not in my backyard) attitude, interference on birds migration routes and so on. This undeniable expansion is pushing wind farms near populated areas throughout the years, where noise regulation is more stringent. That demands solutions for the wind turbine (WT) industry, in order to produce quieter WT units. Focusing in the subject of airfoil noise prediction, it can help the assessment and design of quieter wind turbine blades. Considering the airfoil noise as a composition of many sound sources, and in light of the fact that the main noise production mechanisms are the airfoil self-noise and the turbulent inflow (TI) noise, this work is concentrated on the latter. TI noise is classified as an interaction noise, produced by the turbulent inflow, incident on the airfoil leading edge (LE). Theoretical and semi-empirical methods for the TI noise prediction are already available, based on Amiet’s broadband noise theory. Analysis of many TI noise prediction methods is provided by this work in the literature review, as well as the turbulence energy spectrum modeling. This is then followed by comparison of the most reliable TI noise methodologies, qualitatively and quantitatively, with the error estimation, compared to the Ffowcs Williams-Hawkings solution for computational aeroacoustics. Basis for integration of airfoil inflow noise prediction into a wind turbine noise prediction code is the final goal of this work.

Numerical Investigation of Passive Flow Control Using Wavy Blades in a Highly-Loaded Compressor Cascade

2018 ◽  
Author(s):  
Bo Wang ◽  
Yanhui Wu ◽  
Kai Liu
Keyword(s):  
Numerical Investigation ◽  
Flow Structure ◽  
Cross Flow ◽  
Leading Edge ◽  
Control Flow ◽  
Streamwise Vortices ◽  
Compressor Cascade ◽  
Control Effect ◽  
Suction Surface ◽  
Highly Loaded

Driven by the need to control flow separations in highly loaded compressors, a numerical investigation is carried out to study the control effect of wavy blades in a linear compressor cascade. Two types of wavy blades are studied with wavy blade-A having a sinusoidal leading edge, while wavy blade-B having pitchwise sinusoidal variation in the stacking line. The influence of wavy blades on the cascade performance is evaluated at incidences from −1° to +9°. For the wavy blade-A with suitable waviness parameters, the cascade diffusion capacity is enhanced accompanied by the loss reduction under high incidence conditions where 2D separation is the dominant flow structure on the suction surface of the unmodified blade. For well-designed wavy blade-B, the improvement of cascade performance is achieved under low incidence conditions where 3D corner separation is the dominant flow structure on the suction surface of the baseline blade. The influence of waviness parameters on the control effect is also discussed by comparing the performance of cascades with different wavy blade configurations. Detailed analysis of the predicted flow field shows that both the wavy blade-A and wavy blade-B have capacity to control flow separation in the cascade but their control mechanism are different. For wavy blade-A, the wavy leading edge results in the formation of counter-rotating streamwise vortices downstream of trough. These streamwise vortices can not only enhance momentum exchange between the outer flow and blade boundary layer, but also act as the suction surface fence to hamper the upwash of low momentum fluid driven by cross flow. For wavy blade-B, the wavy surface on the blade leads to a reduction of the cross flow upwash by influencing the spanwise distribution of the suction surface static pressure and guiding the upwash flow.

Unsteady Numerical Simulation of Shock Systems in Vaneless Counter-Rotating Turbine

2005 ◽  
Author(s):  
Huishe Wang ◽  
Qingjun Zhao ◽  
Xiaolu Zhao ◽  
Jianzhong Xu
Keyword(s):  
Numerical Simulation ◽  
Mach Number ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Nozzle Design ◽  
Suction Surface ◽  
Rotor Wake ◽  
Wake Interaction ◽  
Unsteady Numerical Simulation ◽  
Almost All

A detailed unsteady numerical simulation has been carried out to investigate the shock systems in the high pressure (HP) turbine rotor and unsteady shock-wake interaction between coupled blade rows in a 1+1/2 counter-rotating turbine (VCRT). For the VCRT HP rotor, due to the convergent-divergent nozzle design, along almost all the span, fishtail shock systems appear after the trailing edge, where the pitch averaged relative Mach number is exceeding the value of 1.4 and up to 1.5 approximately (except the both endwalls). A group of pressure waves create from the suction surface after about 60% axial chord in the VCRT HP rotor, and those waves interact with the inner-extending shock (IES). IES first impinges on the next HP rotor suction surface and its echo wave is strong enough and cannot be neglected, then the echo wave interacts with the HP rotor wake. Strongly influenced by the HP rotor wake and LP rotor, the HP rotor outer-extending shock (OES) varies periodically when moving from one LP rotor leading edge to the next. In VCRT, the relative Mach numbers in front of IES and OES are not equal, and in front of IES, the maximum relative Mach number is more than 2.0, but in front of OES, the maximum relative Mach number is less than 1.9. Moreover, behind IES and OES, the flow is supersonic. Though the shocks are intensified in VCRT, the loss resulted in by the shocks is acceptable, and the HP rotor using convergent-divergent nozzle design can obtain major benefits.

scholarly journals Reduction of Unsteady Blade Loading by Beneficial Use of Vortical and Potential Disturbances in an Axial Compressor With Rotor Clocking

1998 ◽  
Vol 120 (4) ◽  
pp. 705-713 ◽  
Author(s):  
S. T. Hsu ◽  
A. M. Wo
Keyword(s):  
Large Scale ◽  
Axial Compressor ◽  
Leading Edge ◽  
Forced Response ◽  
Suction Surface ◽  
Blade Loading ◽  
Beneficial Use ◽  
Unsteady Loading ◽  
Vortical Disturbance ◽  
First Time

This paper demonstrates reduction of stator unsteady loading due to forced response in a large-scale, low-speed, rotor/stator/rotor axial compressor rig by clocking the downstream rotor. Data from the rotor/stator configuration showed that the stator response due to the upstream vortical disturbance reaches a maximum when the wake impinges against the suction surface immediately downstream of the leading edge. Results from the stator/rotor configuration revealed that the stator response due to the downstream potential disturbance reaches a minimum with a slight time delay after the rotor sweeps pass the stator trailing edge. For the rotor/stator/rotor configuration, with Gap1 = 10 percent chord and Gap2 = 30 percent chord, results showed a 60 percent reduction in the stator force amplitude by clocking the downstream rotor so that the time occurrence of the maximum force due to the upstream vortical disturbance coincides with that of the minimum force due to the downstream potential disturbance. This is the first time, the authors believe, that beneficial use of flow unsteadiness is definitively demonstrated to reduce the blade unsteady loading.

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