Use Of Vortex Generators Research Articles

CFD Analysis of Counter-Rotating Vane-Type Wing Vortex Generator for Regional Aircraft

Vortex generator is a component that has a significant impact on aircraft performance. The function of the vortex generator is to create vortices that can optimize the aerodynamic performance of aircraft wings by avoiding air flow separation and increasing lift at high angle of attack. Vortex generator can provide increased lift during take-off and landing due to the increased wing angle of attack. Although the use of vortex generator can be carried out using an experimental approach, a computational fluid dynamic approach to determine the influence of geometric parameters and placement of the vortex generator needs to be carried out. The aim of this research is to determine the effect of parameters like placement on the wing chord, height of the boundary layer, length, shape, angle of incidence and distance between pairs on the lift and drag. The model used as a computational fluid dynamic calculation model is the Spalart Allmaras transient model. As a result, vortex generator does not always have a good effect on aerodynamics. All configurations have a negative influence on the lift and drag values, but the flow separation phenomenon can be reduced significantly. Of all the configurations, the best configuration is obtained by exhibiting an ogive shape, positioned at 13.8% of the chord length, set at a 13o angle of incidence. The vortex generator should have a height closely matching the boundary layer, with a length 6.5 times the height and a pair spacing of 6.7 times the height

Application of passive vortex generators to enhance vertical mixing in an open raceway pond

A novel use of vortex generators in a raceway pond is described here, with the flow field quantitatively simulated using computational fluid dynamics using the large eddy simulation turbulence model. Persistence lengths of the swirling motion generated by the vortex generators indicate that significant vertical mixing can be achieved by placing vortex generators in the straight section opposite the paddle wheel, downstream of the first hairpin bend. Relatively simple vortex generators are capable of creating stronger swirling motions that persist for a longer distance than those created by the paddle wheel. For optimal performance, vortex generators are positioned side by side but in opposite directions, and their diameters should be equal to or slightly less than the desired liquid depth. The optimal length of a 0.18 m diameter vortex generator in a 0.2 m deep pond was determined to be 0.3 m. Furthermore, it has been demonstrated that a longer persistence length is achieved by inducing a swirling motion with its rotational axis parallel to the primary flow direction.

Study on vortex generator on automobile and airplane

A vortex generator is a compact device that can be installed on automobiles and airplanes to enhance aerodynamic efficiency. The use of vortex generators on automobiles and airplanes is briefly described in this study. It begins by outlining the working theories and categorizations of vortex generators, which reactivate the boundary layer to postpone airflow separation. Second, this study examines the use of vortex generators on automobiles and trucks, positioned at the back of these vehicles to reduce air drag and improve fuel efficiency. Studies show that vortex generators can increase vehicle fuel economy by 10% to 20%. This study examines how vortex generators improve airplane efficiency and lift by controlling the airflow above the wings. In general, if a vortex generators design is appropriate for automobiles and airplanes, it can improve aerodynamic performance. This article lists several sources regarding the use of vortex generators and their benefits. In short, the future development of vortex generators will tend to be intelligent, material optimization, and environmental protection, aiming to provide more efficient, reliable, and intelligent fluid control solutions, and bring greater economic and social benefits to various industrial applications.

Design and Numerical Study of Serpentine Duct using Flow Controllers for Flow Characteristics Enhancement

In the current work, computational study has been carrying out on the both baseline serpentine duct to know the flow behaviour and baseline with vortex generator to know the effect of vortex generators on the flow properties of the duct. A set of vortex generators are chosen for the study, by keeping all other parameters constant. Here in current work, for modelling the duct and vortex generator CATIA V5 is used; to discretizing the geometry ICEM CFD is used. For the analysis, the computational fluid dynamics tool FLUENT is used, SST k-ù model available in the FLUENT is used for the computations, and the results of current work will be validated with experimental results and shows that they are converged. Use of vortex generator in the current work proved extremely effective in enforcing the active flow control. Results obtained in this work are to study the pressure recovery at the engine face. The results ensure that the current work on the baseline model of serpentine inlet duct and model with vortex generator comparison is well established in case of pressure recovery and decrease in engine face distortion. After comparing the result of both baseline duct and duct with vortex generator we are expecting at least 25-35% of pressure recovery at the engine face. In the present study significant improvements characterized by an improved pressure recovery and decrease in distortion are observed over the baseline model of serpentine duct for vortex generator model. This reduction in pressure loss and distortion enhances the engine performance of thrust and also improves the overall performance of the engine.

Impact of vortex generator and two-phase MWCNT-MgO/water hybrid nanofluid on thermo-hydraulic performance and exergy and energy efficiency of a solar collector under Kuwait climatic conditions

The effect of curved vortex generators and two-phase MWCNT-MgO/water hybrid nanofluid (HNF) on thermo-hydraulic performance and exergy and energy efficiency of a solar collector in a turbulent flow regime is examined in this study. The simulations performed for the climatic conditions of Kuwait. The two-phase DWCNT-MgO/water HNF is modeled using the mixture model. The numerical study is performed for DWCNT-MgO/water HNF with a volume fraction (φ) range of 1–3%, Reynolds number (Re) range of 5000–20,000, and four Pitch Ratio (PR = 0 (Case A), PR = 0.1 (Case B), PR = 0.2 (Case C) and PR = 0.3 (Case D)). It is found that the average Nusselt number (Nuav) and pressure drop (Δp) are enhanced with Re and φ. At φ = 3% and Re = 20,000, placing the vortex generator with a PR = 0.3 (Case D) inside the solar collector causes the Nuav to improve by 83.09% as compared to the solar collectors without turbulators. In addition, the results demonstrated that the use of vortex generators is desirable in all PRs. For Case D and φ = 3%, the exergy efficiency is improved by 45.02% as Re is enhanced from 5000 to 20,000.

The use of vortex generators to improve the take-off and landing characteristics of transport category aircraft

The issue of using vortex generators to improve the take-off and landing characteristics of a transport category aircraft has been considered. Three directions have been analyzed. The first: the installation of vortex generators on the nacelles of the main engines to increase the maximum value of the lift coefficient in landing modes. The second: the installation of vortex generators on the upper surface of the flap to increase the lifting characteristics of the wing by improving the flow around the flap. The third: the installation of vortex generators in the tail unit to increase the efficiency of control surfaces and reducing handling speeds. Examples of the use of vortex generators in each of the directions are given. It is shown that the improvement of the aerodynamic characteristics of the aircraft is possible in the presence of wing separation boundaries on the lifting surfaces in flight operating modes and the elimination of these zones by installing vortex generators. The results of computational studies, experiments in wind tunnels, as well as data from flight tests of an experimental aircraft confirming the effectiveness of using vortex generators are presented. The concept of increasing their stability by installing vortex generators in places with maximum flow velocity is proposed. Considering this concept, new locations for installing vortex generators on the upper surface of the flap, as well as on the fin of an experimental aircraft for repeated flight tests have been selected. The installation of vortex generators on the fin involves increasing the efficiency of the rudder to reduce the handling speeds. The possibilities of optimizing the parameters of the installation of vortex generators are considered. Recommendations are given on the choice of shape, size, and angles of their installation, depending on the tasks solved with the help of vortex generators and considering the possible increase in drag from their installation.

Turbulent Fluid Flow and Heat Transfer Enhancement Using Novel Vortex Generator

One of several effective methods for improving heat transfer in heat exchangers is the use of vortex generators in channels. The flow of fluid through a channel with a vortex generator is disrupted by the development of recirculation zones on the step wall, which improves fluid mixing and heat transmission. The current work investigates the flow and heat transfer of turbulent fluid flow through channels with various vortex generator designs mathematically (triangular, half-circle, and quarter circle). The finite volume method (FVM) is used to discretize and solve the continuity, momentum, and energy equations. The SIMPLE algorithm approach is used to connect the pressure and velocity fields within the domain. The effect of geometrical factors such as step height (2, 3, 4, 5, and 6 mm) on the flow and heat fields is demonstrated and analyzed, as is the effect of Reynolds number. As the step height increases, so do the surface Nusselt number and skin friction coefficient, which peak at 4 mm. According to the findings, as Re increases, so does the average Nusselt number. The quarter circle vortex generator has the best thermal-hydraulic performance at a 4 mm amplitude height, followed by the triangle vortex generator. The simulation results are consistent with those found in the literature.

Numerical study on the use of shear-thinning nanofluids in a micro pin-fin heat sink including vortex generators and changes in pin shapes

Background: The use of passive strategies in microchannel heat sinks allows for increasing the device’s efficiency. The combined use of vortex generators, change of shape of the pins, and shear-thinning nanofluids allow increasing the mixing capacity of the flow without a significant increase in the pressure drop. Method: In this study, we numerically investigated the use of water and two hybrid shear-thinning nanofluids in a microchannel heat sink. In addition, the use of vortex generators in the vertical walls of the microchannel and the change in pin shape from circular to hexagonal was evaluated. The simulations were performed in three dimensions with large-scale meshes without considering symmetry. Findings: From the studied cases, the addition of vortex generators increased the heat transfer rates significantly (by more than 20%) with a considerable increase in pressure drops in the Newtonian fluid. By contrast, in shear-thinning fluids, the pumping cost is reduced by an average of 20%.

On the combined use of Vortex Generators and Gurney Flaps for turbine airfoils

While Vortex Generators (VGs) and Gurney Flaps (GFs) are commonly used for airfoil flow control, studies of a combination of the two devices are rare. The present investigation aims at examining the combined effect of VGs and GFs on a 20% thick airfoil. To this end, a wind tunnel investigation coupled with a computational study was performed. The present paper presents force, pressure and Stereo Particle Image Velocimetry measurements, along with Unsteady Reynolds Averaged Navier Stokes simulations.

About the Use of Vortex Generators to Improve Aircraft Aerodynamics

About the Use of Vortex Generators to Improve Aircraft Aerodynamics

Heat Transfer Characteristic on Wing Pairs Vortex Generator using 3D Simulation of Computational Fluid Dynamic

Vortex generators are addition surface that can increase heat transfer area and change the fluid flow characteristics of the working fluid to increase heat transfer coefficient. The use of vortex generators produces longitudinal vortices that can increase the heat transfer performance because of the low pressure behind vortex generators. This investigation used delta winglet vortex generator that was combined with rectangular vortex generator to Reynold numbers ranging 6,000 to 10,000. The parameters of Nusselt number, friction factor, velocity vector and temperature distribution will be evaluated.

PROPELLER CAVITATION AND INDUCED VIBRATION

The demand to increase the efficiency of propellers has led to optimized propeller blade designs finding their way into the construction of high-powered commercial vessels, such as containers or LNG carriers and certain categories of passenger vessels, to mention but a few. It has become increasingly common to see the propeller tip rotate closer to the hull surface, sweeping the thick turbulent boundary layer attached to the hull, causing fluid structure interaction. At the same time, increasing the loading on marine propellers can lead to problems, such as noise, hull vibration, and cavitation. The degree above which, such phenomena as propeller cavitation can be the main perpetrators for intensive vibration during operation, their diagnosis and the solutions to mitigate this risk, such as the use of vortex generators, are discussed here, taking into account cost and longevity of the vessel as well as the involvement of classification rules.

Evaluation of Vortex Generators in the Heat Transfer Improvement of Airflow through an In-Line Heated Tube Arrangement

Improving heat transfer from surface to airflow is a current research concern for enhancing energy efficiency. The use of vortex generators for improving heat transfer from the surface to the airflow is very effective. Therefore, this study focuses on applying flat and concave vortex generators with and without holes in order to improve heat transfer. In this study, the number of pairs of vortex generators was varied from one to three pairs at a certain angle of attack for various forms of vortex generators. The airflow velocity through the duct was varied in the range of 0.4 to 2.0 m/s at 0.2 m/s intervals. From the investigation results, we observed that the highest thermal performance was found with the use of concave delta winglets without holes for various pairs of vortex generators in terms of the overall Reynolds number. The highest thermal enhancement factor was found to be around 1.42 at a Reynolds number of approximately 9000. From this study, it was also shown that the lowest cost–benefit ratio was about 1.75 at a Reynolds number of approximately 3500 for three pairs of vortex generators.

Effect of new punched vortex generators in a rectangular channel on heat transfer using Taguchi method

ABSTRACT In this study, the effects of New Punched Rectangular Vortex Generators (NPRVGs) and Punched Rectangular Vortex Generators (PRVGs) inside a rectangular channel on heat transfer augmentation, Nusselt number, and friction factor were experimentally investigated. Temperature contours and average Nusselt numbers analyzed heat transfer characteristics resulting from the use of vortex generators. Furthermore, this study investigated the optimum values of the design parameters within the system of vortex generators by using the Taguchi method, and the orthogonal experimental plan was made for L16 (43x21). Reynolds numbers (5181, 10363, 20328, 25510), winglet arrangement, winglet attack angles (15°, 30°, 45°, 75°) and a distance of punched winglet from the channel bottom (b) to constant winglet height (e = 25 mm) (b/e = 0.04, 0.12, 0.2 and 0.36) were determined the working parameters in the experiments. Measurements are carried out for a rectangular channel with aspect ratio AR = 2, winglet transverse pitch (S) to longitudinal winglet height (e) ratio of S/e = 0.67 and a winglet height (e) to channel height (H = 25 mm) ratio of e/H = 1. Heat transfer rates of NPRVGs and PRVGs were compared to the obtained results for a smooth channel. The heat transfer performance is improved considerably by the NPRVGs. The maximum thermal performance factor increased from 0.99 to 1.89 owing to the combination of the vortex generator and the newly punched hole.

Heat Transfer Across Tube Banks With a Passive Control Vortex Generator in Steady One-Directional and Oscillatory Flows

Fluid can flow in one-directional (normal flow) or oscillatory conditions. Fluid flow in some energy system involved oscillatory flow condition. The use of vortex generator has been proven to improve heat transfer in the case of one-directional flow but the impact of vortex generator in oscillatory flow condition is yet unknown. This study focusses on the heat transfer performance across a heated tube banks using a Computational Fluid Dynamics (CFD) model. Two flow conditions were modelled: steady one-directional and oscillatory flow conditions. Two-dimensional CFD models of steady flow and oscillatory flow were solved using the SST k-? turbulence model for two different cases of heated tube banks with and without the vortex generators. The heat transfer performance for both flow conditions were analysed by considering a heat transfer parameter known as Colburn-j factor. Results showed that the use of a vortex generator increased the heat transfer enhancement, regardless of the flow conditions. However, it is also noted that the heat transfer behaviour in a steady flow and an oscillatory flow is not the same, especially with the appearance of secondary flows in the system. The difference is discussed with respect to dimensionless quantity of Colburn j-factor, the non-dimensionless quantity, and the amplitude of temperature field. The result indicates that the heat equation in the steady flow condition is not very suitable to be directly used in oscillatory flow conditions. Appropriate heat equation needs to be properly addressed for situations that involve oscillatory flow motion.

Performance Improvement of a Forced Draught Cooling Tower Using a Vortex Generator

Cooling systems using colling towers are often an important element in a production process and always involve water or energy consumption. Therefore, increasing the efficiency of the colling tower will reduce water and / or energy consumption. In order to increase the efficiency of colling tower energy consumption, the most studied part is the fills, where heat transfer occurs. However, there are no studies on the use of vortex generators in colling tower fills. Hence the aim of this study was to evaluate the performance improvement in a forced draught cooling tower using a vortex generator. It was conducted on a laboratory scale using single fill as a trial medium. The fill was made of 3-mm acrylic with dimensions of 30 × 30 × 1950 mm. A three-unit vortex generator was placed inside the fill. The rectangular vortex generator was made of 0.5-mm thick aluminium and had a size of 50 × 10 mm. Data were retrieved for the fills with and without a vortex generator. Water and air discharge of 1 L/minute and an inlet water temperature of 60°C were maintained. The results indicated that the effectiveness of the fill with a vortex generator was increased by 90.72% compared to the fill without a vortex generator.

Experimental and numerical studies of air flow and heat transfer due to insertion of novel delta-winglet tapes in a heated channel

The use of vortex-generators is one of the most effective ways to enhance the thermal performance of heat exchangers. The vortex-generators are commonly designed and made in two forms: wings and winglets. In this work, an investigation is carried out on a heated channel equipped with the novel delta-winglet tapes (DWTs). Eight non-uniform arrangements of the delta-winglets with variable pitches and heights along the axial direction are proposed and compared with the original model as the uniform case. All cases are studied experimentally, and also numerical simulations are used to analyze the corresponding mechanisms. The thermal and hydrodynamic characteristics are reported using the dimensionless parameters of Nusselt number, friction factor, and overall performance index for the Reynolds number range between 1643 and 8215. The results show that equipping the channel with the non-uniform DWTs affects the performance of the channel, and in some cases, it leads to better thermal performance compared to the uniform tape. The range of the variations is between 0.88 and 1.14 times for the Nusselt number and between 0.95 and 1.49 times for the friction factor. In general, placing the delta-winglets with longer height or shorter pitches at the upstream of DWTs improves the channel's thermal performance. The maximum Nusselt number ratio of 1.62 is recorded for the DWT in which the height of delta-winglets is from High to Low with the uniform arrangement of pitches. On the other hand, the DWT with the uniform heights of delta-winglets and Low to High arrangement of pitches possess the best overall performance among the studied cases. The performance index for this model is in the range of 1.44 to 1.07.

2D optimization of a Small Horizontal Axis Wind Turbine blade using flow control techniques

In this work, the optimization of the efficiency of a small horizontal axis wind turbine (SHWT) blade segment is presented. Typically, SHWTs have a radius of 1.5 to 3.5 m and a hub height of around 15 m from the ground. SHWTs operate in a relatively small Reynolds numbers range (up to 1.5x106) and are installed inside the atmospheric boundary layer. This operational environment is characterised by volatile air flow, making the flow over the blade prone to separation. In order to counter this flow behavior, a set of flow control techniques is introduced and studied. These techniques control the flow, either passively, solely by the inclusion of blade add-ons, or actively, by adding energy to the boundary layer. More specifically, two passive flow control techniques and one active flow control technique are modelled and tested on a wind turbine blade segment. The passive techniques implemented in this study are based on the use of vortex generators and tubercles. Vortex generators are small vanes attached vertically to the lifting surface and are widely used in aerospace applications with varying degrees of success. Tubercles, which is a novel flow control technique, are sinusoidal modifications of the blade’s leading edge. The original concept has been inspired from the characteristic flipper of the humpback whale (Megaptera Novaeangliae). Regarding the active flow control technique, a dielectric barrier discharge (DBD) plasma actuator (PA) is used, a technique that adds momentum on the local flow, close to the blade’s surface, by ionizing the air. The impact on the blade aerodynamic efficiency for each technique are evaluated and presented. The results from this evaluation show that flow control techniques can offer a considerable benefit to SHWT by improving the blade’s aerodynamic characteristics, i.e. by increasing the blade lift-to-drag ratio and thus, improving their critical performance efficiency factor.

Aerodynamic performance enhancement of an Airfoil using trapezoidal vortex generators

PurposeFlow separation on wings, blades and vehicles can be delayed or even suppressed by the use of vortex generators (VG). Numerous studies, documented in the literature, extensively describe the performance of triangular and rectangular VG winglets. This paper aims to focus on the use of non-conventional VG shapes, more specifically an array of trapezoildal-perforated VG tabs.Design/methodology/approachIn this study, computational fluid dynamic simulations are performed on an inline array of trapezoidal VG with various dimensions and inclination angles, in addition to considering perforations in the VG centers. The methodology of the present numerical study is validated with experimental data from the literature.FindingsThe performance and the associated flow structures of these tested non-conventional VG are compared to classical triangular winglets. For the proposed non-conventional trapezoidal VG, at the onset of stall, a 21% increase of lift over drag on the airfoil is observed. The trapezoidal VG enhancement is also witnessed during stall where the lift over drag ratio is increased by 120% for the airfoil and by 10% with respect to the triangular winglets documented in the literature.Originality/valueThe originality of this paper is the use of non-conventional vortex generator shape to enhance lift over drag coefficient using three-dimensional numerical simulations.

Performa Termal dan Hidrolik Aliran Udara Melalui Vortex Generator Berlubang Tipe Concave Rectangular Winglet di dalam Saluran Persegiempat: Studi Eksperimen

Fin and tube heat exchangers use gas as a cooling/heating medium on the fin side. The low thermal conductivity of gases results in high thermal resistance, which results in a low rate of heat transfer. Therefore, the researchers sought to reduce thermal resistance on the fin side. This study aims to increase heat transfer by reducing thermal resistance using a longitudinal vortex generator. However, the use of vortex generators will increase the pressure drop. Perforated vortex generators were investigated in this study to overcome this problem. Concave rectangular winglet vortex generator at an angle of attack of 30° with variations of without hole, one, two, and three holes were studied. In this experiment, the number of pairs of vortex generators was varied from one to three pairs. A plate on which the vortex generator is mounted is heated at a heat rate of 35 W. Air enters the channel through the straightener at variations in the velocity of 0.4 m/s to 2 m/s at intervals of 0.2 m/s. The results showed that the value of the convection heat transfer coefficient for the use of perforated concave rectangular winglet vortex generators was 85.4% higher than the baseline. This value is 13.7% higher than the use of perforated rectangular winglet vortex generators. Whereas the value of pressure drop for the use of perforated concave rectangular winglet vortex generators is five times higher than that of the baseline. This value is 104.9% higher than the use of perforated rectangular winglet vortex generators.