Typical Airfoil Research Articles

Numerical Analysis of Air Flow in an Industrial Refrigeration System and Its Effect on Energy Consumption

Refrigerated display cabinets as a type of cooling system is preferable commonly in food shops and grocery store to prevent foods from warm air. They do not have much more efficient compared to the cabinets with glass doors because of the interactions between air curtain. This paper presents experimental and numerical methods to seek energy performance of the horizontal refrigerated display cabinets in terms of design parameters. Two geometry with/without airfoil were designed and evaluated the effects of discharge velocity to create more efficient air curtain. 2D Computational Fluid Dynamics (CFD) model was performed to assess the effect of discharge flow on the cooling load performance of the horizontal display cabinet. The results showed that the airfoil design has increased the efficiency of the air curtain with achieving a more effective air curtain, resulted in mitigation of the ambient warm air infiltration into the cabinet. The return air temperature of the cabinet with airfoil decreased from 272.45 K to 270.62 K compared to the one without airfoil due to more effective air curtain. In this way, the cooling capacity of the refrigeration system has been decreased by 3.82% with airfoil usage. It is also concluded that the air temperature inside the cabinet and the cooling capacity have been decreased by 3.5°C and 2.82%, respectively when Case 7 for used the new type airfoil and Case 1 with the same air velocity are compared.

Design load provisions for simulating the critical effect of downbursts on wind turbines

Wind turbines are among the rapidly growing sources of sustainable energy. The review of design codes for this type of structure shows a lack of procedures for estimating the wind loads on wind turbines due to high-intensity wind events such as downbursts. There is a challenge in the analysis and design of wind turbines under downbursts because of the sudden and localized nature of such events, which makes the forces acting on the tower and blades dependent on the characteristics of the event. As such, the objective of the current study is to develop design load provisions that can simulate the critical effect of downbursts on wind turbines. These provisions are developed in two phases. Identifying the peak effects of the moving mean component of the downburst and determining the associated critical profiles are the aim of the first phase. To achieve this task, a comprehensive parametric study is conducted using the previously developed numerical model, HIW-TUR, on a wide range of wind turbine sizes and airfoil types in order to assess the critical response of wind turbines under the mean component of downbursts. The study takes into account the variations in the downburst size and its location relative to the tower center. Then, dynamic analyses under turbulence are conducted in the second phase using the open-source code, FAST, to determine a downburst gust response factor to magnify the effect of the mean component. The downburst gust response factor is then superimposed with the mean component profiles to present a complete set of design provisions. An example is presented to demonstrate the application of the developed loading provisions on a real wind turbine and to compare with the extreme synoptic wind load cases specified by the International Electro-technical Commission Loading Code.

Comparative Study of the Blade Number and Airfoil Profile Impacts on the Twist/Chord Distribution of a Small Wind Turbine Blade

The blade number and airfoil profile effects on the blade shape of a small horizontal-axis wind turbine (SHWT) were investigated. For this purpose, the NACA4412, SG6042, and SG6043 airfoils, as well as 2, 3, and 4 blades, were considered. Then, two optimization processes were used: first, the blades were designed to maximize the power coefficient ( C p ), and then a multiobjective optimization that included both maximizing C p and maximizing the starting torque ( Q s ) was employed. The differential evolution (DE) algorithm was employed to perform the optimization, and the blade element momentum aerodynamic approach was used to conduct the relevant computations. Also, to ensure the performance of the optimal blades, the computational fluid dynamics method was employed as well. The findings revealed that regardless of the number of blades and the type of airfoil, raising the twist angle ( θ p ) and chord length ( c ) along the radial direction of the blade, especially at the root part, helps increase the Q s . It was observed that increasing the number of blades does not have a significant effect on the θ p distribution of the selected airfoils, but the c of the blades fitted with all three airfoils decreases. Regardless of the number of blades, while the geometry of blades utilizing the NACA4412 and SG6042 airfoils are close to each other, the blade with the SG6043 airfoil has the shortest c , which reduces the generated Q s of blades fitted with this airfoil. The results also establish that by increasing the number of blades from 2 to 3, the power coefficient ( C p ) of the blades fitted with all three airfoils increases, but by further increasing the number of blades from 3 to 4, the change in C p completely depends on the airfoil profile.

Study on Thermal–Hydraulic Characteristics of Novel Channels for Printed Circuit Heat Exchanger Using Supercritical CO2

Abstract Two new types of printed circuit heat exchanger (PCHE) channels are proposed based on the typical airfoil fin PCHE channel proposed in literatures (standard channel) to further improve the thermal–hydraulic performances of airfoil fin PCHE channel. The small shuttle fins and oval fins are employed between the adjacent two airfoil fins of two novel channels, respectively. Using supercritical CO2 as the working fluid, the thermal–hydraulic performances and enhancement mechanisms of the novel channels are numerically investigated. The results show that the channel with shuttle fins has the best comprehensive performance. The Nusselt number of the channel with shuttle fins is 6.7–26% larger, and the f-factor is 8.3–18.6% larger than that of the standard channel under the selected conditions, which leads to a 3–19.1% increase in the PEC (comprehensive performance evaluation criteria). The Nusselt number of the channel with oval fins is 9–27.3% larger, and the f-factor is 26.6–43.4% larger than that of the standard channel, which leads to a 1–15.3% increase in the PEC. The applications of small fins between the adjacent two fins can effectively reduce the low-velocity region area and enhance the local disturbance, thereby effectively improving the thermal–hydraulic performance. The enhancement mechanism of the novel fin PCHE channel structure can be well explained by the principle of field synergy. It can be found that the synergies of the temperature gradient field and the velocity field in two novel channels are significantly improved.

NUMERICAL SIMULATION OF THE FLOW AROUND AN AIRFOIL TYPE TRANSPORT VEHICLE NEAR THE GROUND

The problem of modeling the flow around an airfoil type transport vehicle near the ground is considered. The flow around the vehicle is turbulent. Nowadays, the most advanced mathematical models of aerodynamics are based on the physical properties of a viscous compressible gas and are based on the Reynolds-averaged Navier – Stokes equations. Mathematical modeling of turbulent flows remains one of the most challenging problems. Reliable prediction of the characteristics of turbulent flows is an extremely important scientific problem. This is due to the complexity and insufficient study of turbulence as a physical phenomenon. The aim of this work is to build a mathematical model, a numerical method, an algorithm for solving the problem, and to develop software for studying the aerodynamic characteristics of a vehicle of the airfoil type. To close the Reynolds-averaged Navier –Stokes equations, the one-parameter Spalart – Allmaras turbulence model was used. The initial system of differential equations is written in a curved coordinate system. The initial and boundary conditions for the flow parameters are formulated. The methodology, algorithm for solving the problem, and software are developed. The finite-volume method was used for numerical integration of the system of differential equations. The problem was solved in a multi-block formulation. The developed methodology of algorithms and a set of programs were tested on standard aerodynamic problems: the flow around a transversely placed circular cylinder and a ball. Numerical modeling of the flow of compressed gas around a vehicle moving near the ground was performed. All calculations were carried out for the Reynolds number Re=1,0*10^6 and the Mach number M=0,4. Numerical simulations were performed on a curved multi-block grid. The influence of the ground on the characteristics of the flow around the vehicle was investigated. The studies have shown that the presence of a nearby ground has a significant impact on the flow characteristics around the vehicle. Thus, in order to ensure the required parameters of vehicle dynamics near the ground, it is necessary to take into account the influence of the ground on its aerodynamic characteristics.

Improved order of magnitude estimate of rotational effects on HAWTs

This work proposes an improved order of magnitude estimate methodology of rotational effects on wind turbines, by applying the partial pressure field concept to the case of rotating wind turbine blades, which allows isolating acceleration that rises as a result of the rotation of the blades; then an order of magnitude scaling is performed to estimate the partial pressure due to rotation for both fully attached flow and massively separated flow. In the case of fully attached flow, it was found that rotational effects are negligible; while in the case of massively separated flow, rotational effects were found to be important. The pressure reduction was found to scale linearly with the aspect ratio inside the separated boundary layer, while it scales quadratically with the aspect ratio in the outer inviscid flow. A new estimate of the Rossby number is proposed, which is found to be the inverse of the pressure reduction coefficient estimate in the outer inviscid flow. Then, a semi-empirical model of the pressure reduction is proposed based on the order of magnitude estimate in the outer inviscid flow. The proposed semi-empirical model is then compared against the reference data of three wind turbines, namely, MEXICO, NREL phase VI, and AVATAR 10 MW rotors; along with the already known centrifugal pumping model. The results showed that the centrifugal pumping alone, inside the separated boundary layer, is not sufficient to produce the large force augmentation observed in experimental data. In contrast, the improved semi-empirical model provided a good agreement with experimental data, thanks to the quadratic scaling of the aspect ratio. And, the new estimate of the Rossby number proved to be advantageous over the existing Rossby number estimate in terms of the dependency on the angle of attack. Furthermore, the tangential and drag force coefficients were found to be strongly dependent on the airfoil type and its corresponding pressure shape. In contrast, the normal and lift force coefficients were found to be less dependent on the airfoil type. The proposed semi-empirical model is still strongly empirical, future work needs to account for the complex effect of airfoil type and its consequent interaction with the outer inviscid flow through the boundary layer.

Blade Design and Aerodynamic Performance Analysis of a 20 MW Wind Turbine for LCoE Reduction

The aim of this study is to develop a blade mass model that incorporates a low-induction rotor (LIR) and a low-specific power concept to reduce aerodynamic loads and lower the Levelized Cost of Energy (LCoE). This blade mass model replaces the traditional simple scaling rule and incorporates the concept of LCoE reduction, presenting not only the mass distribution in the blade span direction but also the stiffness distribution. In order to achieve the desired reduction in LCoE, we developed a mathematical model that expresses blade mass as a function of the axial induction factor, which influences the aerodynamic load on the blade. We used this model to determine geometries of various low-induction rotors for 20 MW class horizontal axis wind turbine, and to identify the axial induction factor that correlates with the lowest blade mass. The chord length and twist angle in the spanwise direction of the blade were determined using PROPID’s reverse design process, based on the specified axial induction factor. Since the low-induction concept is not aerodynamically optimal, a low-specific power design approach was also adopted. This involved increasing the blade length and shifting the power curve to the left. By doing so, the AEP is increased, directly contributing to a reduction in the LCoE. Mass per unit length of the blade was presented, reflecting the distribution of airfoil type, blade geometry, and shapes of internal structures such as spars and webs.

Aerodynamic lift coefficient prediction of supercritical airfoils at transonic flow regime using convolutional neural networks (CNNs) and multi-layer perceptions (MLPs)

Designing an aircraft involves a lot of stages, however, airfoil selection remains one of the most crucial aspects of the design process. The type of airfoil chosen determines the lift on the aircraft wing and the drag on the aircraft fuselage. When a potential airfoil is identified, one of the first steps in deciding its optimality for the aircraft design requirements is to obtain its aerodynamic lift and drag coefficients. In the early stages of trying to select a candidate airfoil, which a whole part of the design process rests on, the conventional method for acquiring the aerodynamic coefficients is through Computational Fluid Dynamics Simulations (CFDs). However, CFD simulation is usually a computationally expensive, memory-demanding, and time-consuming iterative process; to circumvent this challenge, a data-driven model is proposed for the prediction of the lift coefficient of an airfoil in a transonic flow regime. Convolutional Neural Networks (CNNs) and Multi-Layer Perceptrons (MLPs) were used to develop a suitable model which can learn a set of usable patterns from an aerodynamic data corpus for the prediction of the lift coefficients of airfoils. Findings from the training revealed that the models (MLPs and CNNs) were able to accurately predict the lift coefficients of the airfoil.

Research on the aerodynamic performance of the F1 racing car rear spoiler with different track characteristics

The rear spoiler of an F1 racing car is the main component that affects its aerodynamic performance. In the race, it is necessary to select the wing with different characteristics according to different track characteristics. In this paper, computational fluid dynamics (CFD) technology is used to study four different types of stationary airfoils, analyze their aerodynamic performance under three different track conditions, combine the characteristics of the track for quantitative analysis, and finally target the most suitable airfoil. Airfoil 2 is suitable for track 1 - Spa Francolchamp, a track with many curves and changeable climate, because of its medium negative lift value. The high negative lift force generated by airfoil 4 is applicable to the high altitude track, for example, Track 2 - The Rodriguez Brothers Track in this study. For airfoil 1, the lowest resistance value is applicable to track 3 - Silverstone, which is a track with many straight tracks and high-speed curves.

Simultaneous aerodynamic and structural optimisation of a low-speed horizontal-axis wind turbine blade using metaheuristic algorithms

AbstractThis work presents a concurrent design and multi-objective optimisation framework of horizontal axis wind turbine blades, made of composite material, for low wind speed. The optimisation model aims to minimise the structural mass of the blade whilst simultaneously maximising the turbine power output, subjected to three constraints viz. blade tip deflection, and Tsai-Hill and von Mises criteria. The design variables are blade shape and details of the internal blade structure. The control points and polynomial interpolation technique were adopted to determine the blade shape while the airfoil types at blade sections remained fixed. The internal blade structure design variables include the thickness of ribs and spars and the carbon fibre thickness and orientations. The blade element momentum approach is utilised to calculate turbine power and structural loads, whereas a finite element method is employed for structural analysis. Twelve multi-objective metaheuristics algorithms are used to solve the proposed multi-objective optimisation problem while their performance is investigated. The results obtained show that the multi-objective cuckoo search algorithm is the most efficient method. This study is said to be the baseline for a future study on multi-objective optimisation which combines two design stages of the composite low-speed wind turbine blades.

Wind turbine optimization through optimal blade shape design for low wind speeds

Current electricity needs continue to rely on depleting fossil fuels such as fossil fuel and coal. The current government effort is to find non-fossil fuel alternative energy sources. Wind energy is one of the efforts to use ecologically friendly renewable alternative energy. Studies on the development and use of new and renewable energy are now undertaken. One of them is a series of research on the utilization of wind in numerous places of Indonesia through the construction of wind turbines. The blade that explicitly makes contact with the wind is one of the most critical sections of a wind turbine. The shape of the airfoil determines whether or not the blade is used. The focus of this research was to determine the optimal type of airfoil by comparing the coefficient of power (Cp), maximum power, and lowest power produced by various NACA (National Advisory Committee for Aeronautics) airfoils. NACA 4410, 4412, and 4415 airfoils were employed in this study.

Research on the pressure distribution under different airfoil types of aircraft

Airfoils produce life force for aircraft, which is the reason for planes flying in the sky. The formation of the airfoil depends on its shape, so airfoil designs play an important role in airplane designs. The airfoil design is also prioritized in the process of aircraft design, its speed of creating affecting the progress of the entire project. The goal of airfoil’s design is not simply to create “good” wings, because it does not exist. This means that when airfoils are adapting to a certain airflow or flying condition, their performance might not be satisfied due to environmental variations. Therefore, the application of Computational Fluid Dynamics (CFD) techniques and the Small Disturbance Equation, this study uses python to perform numerical analysis to simulate the surface pressure of the ideal wings under certain flying statues, and then applying a series of algorithms to calculate the shape of the target airfoils, which can find the most suitable airfoil shape under the flying circumstances. According to the researches, the best possible wings satisfying which the pressure below be as larger as possible than the pressure above to produce lift force, is f(x) = k*(x-1)∧4 for downside and f(x) = k*sin(pi(x-1)) for the top. Besides, after a series of calculations, this paper realized that the smaller the k value can be, the better fit it is to an ideal simulated airfoil shape.

Effect of Vortex Generators on Airfoil NACA 632-415 to Aerodynamic Characteristics Using CFD

To determine the aircraft’s flight performance, the airfoil type must be considered when designing the wing. A vortex can form when the airfoil travels through a fluid stream with a difference in velocity and pressure around it. Airfoil modification is carried out to delay the occurrence of flow separation by adding a vortex generator. This paper discusses how adding the vortex generator helps slow the stall’s onset and how the vortex generator affects the fluid flow and aerodynamic forces acting on the NACA 632-415. The vortex generator profile is positioned at an x/c = 20% of the chord line’s direction from the leading edge. The variation used is an airfoil’s angle of attack (α). Some parameters to be evaluated include the coefficient lift force (C­­L), the coefficient drag force (CD), and the gliding ratio (C­­L/CD). The research was conducted by the CFD method based on the angle of attack that produces the coefficient lift and drag forces. The addition of the vortex generator can delay the flow separation, increase the lift force coefficient by about 24.9%, the drag force coefficient by about 2.7%, and the gliding ratio by 9.1%.

Aerodynamic Performance Improvement on NACA 4415 Airfoil by Using Cavity

This study uses a numerical method to analyze the cavity's use on the airfoil's trailing edge and the aerodynamic effects it generates. The type of airfoil used is NACA 4415. The variations in the Reynolds number examined in this study are 2×105 and 3×105. The governing equation is the Reynolds Averaged Navier-Stokes paired with the k-ε turbulence model. This study concludes that the cavity can increase Cl in the airfoil but cannot delay the stall. The increase in Cd is also a negative effect of using a cavity in the airfoil. The cavity can increase Cl by increasing the pressure on the lower side near the trailing edge. Meanwhile, the cavity increases Cd because it creates a separation of the fluid flow, forming a vortex when viewed in a streamlined form of fluid flow.

NACA0009 ve NACA4415 Kanat Profillerinin Sayısal ve İstatistiksel Aerodinamik Performans Analizi

In this numerical and statistical study, lift and drag coefficient performances of NACA-0009 and NACA-4415 airfoils were evaluated in accordance with various attack angle at constant velocity of wind. Lift and drag coefficients of airfoils was numerically determined by computational fluid dynamics code ANSYS FLUENT. Analysis design of numerical calculations was implemented using L16 orthogonal array based on Taguchi method. Angles of attack and airfoil types were considered as control factors. The optimum level and effect of each control factor on responses was statistically implemented using analyses of Signal-to-Noise ratio and variance. As a result of this study, maximum lift and minimum drag coefficient were achieved by using NACA4415 airfoil compared to NACA0009 airfoil. The increase of the angle of attack leads to the increase on the lift and drag coefficients for both airfoils.

NACA2412 airfoil based method for design and aerodynamic analysis of small HAWT using modified BEM approach

Efficient utilization of wind energy depends on careful selection and suitable design of Wind Turbine (WT) blades. Small scale Wind Turbines (SWT) normally operate in the low range of Angle of Attack (AoA). This makes the task even more difficult for designing and optimization of WT blades. This article deals with an airfoil based computational approach to design the blade for a standalone small scale Horizontal Axis Wind Turbine (HAWT). A procedure has been proposed to find the important parameters and analyze the performance characteristics for a three bladed HAWT operating under the wake rotation. Computational code has been written to find optimum blade profile. Twist angle variation, chord length and other related parameters are determined with the help of program. Comparison between different types of airfoil has been made to figure out the most suitable one. Airfoil selection and design approach are intended to make Wind Turbine blade efficient specially under low range of AoA. Characteristics of the Wind Turbine obtained analytically from this procedure are compared with several other reported earlier in some of the literatures. The result obtained by the proposed procedure is simpler and more efficient than BEM theory – a method normally employed for blade design.

Strength analysis of a blade with different cross-sections

The efficiency of horizontal axis wind turbine (HAWT) blades is examined in this paper concerning the effect of cross-section airfoil type. Three different airfoils were examined: symmetric (NACA 4412), asymmetric (NACA 0012), and supercritical (NACA 4412). (EPPLER 417). The analyses that were performed combined theory and experiment. Theoretical analyses were carried out using Fortran 90 code and the blade element momentum-based Qblade code. The blade was created using SolidWorks software and a 3D printer for testing purposes. The findings of experimental tests supported the conclusions of the theory. Research revealed that the EPPLER 417 blade, which has a supercritical airfoil, performed better than other examined objects. NACA 4412, NACA 0012, and EPPLER 417 each have a power coefficient of 0.516, 0.492, and 0.510. According to the experimental data, the EPPLER 417 airfoil outperforms other air-foils in terms of power and speed reduction. To calculate the deformation and stresses of the three blades with various cross sections, CFD analysis was done in ANSYS Workbench. The CFD results showed that NACA 4412 has the highest strength but EPPLER 417 was considered the optimum cross-section based on power generation and acceptable stress values.

Experimental study of printed-circuit heat exchangers with airfoil and straight channels for optimized recuperators in nitrogen Brayton cycle

• The recuperator has been reported as the largest component in nitrogen Brayton cycles. • The compactness and economics can be enhanced by adopting advanced channel shapes. • Experiments of advanced channel shapes, such as airfoil and straight, were performed. • New correlations for the airfoil channel were developed to design the recuperator. • Optimal design results of recuperator were discussed in terms of flow channel shapes. In this study, experiments with straight and airfoil channels of printed-circuit heat exchanger (PCHE) are conducted within a 3 % heat balance difference to investigate thermal-hydraulic performances for nitrogen (N 2 ) Brayton cycle recuperator. The results reveal that the airfoil PCHE has higher heat transfer performance and pressure drop than the straight PCHE. In the case of straight PCHE, the Gnielinski correlation for heat transfer and Blasius correlation for pressure drop show sufficient predictability. For airfoil PCHE, new correlations for Nusselt number and friction factor are developed to predict the experimental data with a maximum error of 2 % for heat transfer and 8 % for pressure drop. Subsequently, the newly developed and other previous correlations for different channel configurations are used to compare the comprehensive performances. The results indicate that airfoil PCHE has the highest comprehensive performance rather than straight, zigzag, and S-shape PCHE channels under the given hydraulic diameter and pumping power conditions. With the validated PCHE 1-D code, the optimal volumes are calculated for target conditions considering the PCHE channel configuration effect. The design result of the airfoil type has the smallest volume compared with other PCHE channel types, which was almost 21 % reduced volume than that of zigzag PCHE.

Investigation of a Newly Developed Slotted Bladed Darrieus Vertical Axis Wind Turbine: A Numerical and Response Surface Methodology Analysis

Abstract In the past few years, wind energy became the most reliable and clean energy source throughout the world. This research broadly has focused on the 2D design of the conventional (without slot) wind turbine blades as well as slotted airfoil blades for places having a low power density of wind. For vertical axis wind turbines, optimum airfoil design plays a vital role in the aerodynamic efficiency of the wind turbine. To get better aerodynamic efficiency, a feasible airfoil criterion of selection, played an important role in the chosen blade design. In this paper, the conventional NACA0018 profile without slots and slotted airfoil profile is selected for measuring the turbine blade performance. The geometry of the computational domain has been created using the solid works software and the computational investigation has been performed using the computational fluid dynamics (CFD) solver ansys fluent 2020 R2 with the help of the shear stress transport (SST k–ω) turbulence model. The simulations are conducted initially with base airfoil and then varying the different structures of slots. After introducing slots in the base airfoil, efficiency was increased in terms of lift coefficient (Cl) and power coefficient (Cp) by 2.32% and 17.94%, respectively at the angle of attack of 15 deg. The results indicate that slotted airfoils have a better lift coefficient and power coefficient compared to an airfoil without a slot. The best turbine operating parameters were found to be 14.82 deg of angle of attack, 1.73 coefficient of lift, and 2.99 tip speed ratio (TSR) by using the response surface methodology (RSM). At these optimal settings, the best Cp response was 0.406. A field experiment was carried out to verify the modeling-optimization outcomes, and the results were within 7% of the model projected results. Thus, this type of slotted airfoil designed for a vertical axis wind turbine (VAWT) can be used to harness wind energy potential more efficiently.

Design and Angle of Contact (AoA) analysis of Remote Control (RC) Aircraft

In this paper, the design of a prototype of Remote Control (RC) aircraft is discussed. It is important and interesting to learn about the workings, terminology, factors affecting to flight, construction, application, and advantage of the aircraft. Also, studied about the designing aeronautics formula rules and analytical equations of aircraft lift force and drag force of a RC airplane for AOA analysis. In addition, aerodynamic performance is carried out on the airfoil type wing to determine the drag and lift forces at maximum speed.