Artificial Vortex Research Articles

Numerical Simulation of Performance Enhancement of Solar Vortex Engine

The solar vortex engine (SVE) has been investigated to generate power using renewable energy. The SVE was constructed from a vortex generation engine (VGE) and solar air collector (SAC). The SVE system primarily utilizes vertical air movement. However, the airflow entering the VGE experiences an obstruction. The purpose of this paper is to propose a new design for the VGE that creates a swirling updraft capable of overcoming air obstruction and reducing energy losses. A 3D numerical model of VGE was developed to visualize vortex generation. The modeling of the VGE is carried using SOLIDWORKS software and ANSYS-FLUENT 18. The improved VGE has six vertical twisted convergence blades connected to six guide vanes to direct updraft air in an anticlockwise swirl. All blades and vanes are housed in a VGE cylinder with a diameter of 20cm and a height of 30cm. The simulation results were validated by comparing with the results obtained from the present experimental model. The simulation results match with a mean difference of less than 5% with the experimental measurements. The results of the current CFD investigation indicate that there is a gradient in air temperature and pressure within the VGE, ranging from the highest values of 314 K and 3.85 Pa to the lowest values of 308 K and 2.42 Pa, respectively. The CFD visualization shows a threefold increase in axial velocity and a fivefold increase in tangential velocity within an artificial vortex. Therefore, it can be concluded that the new VGE construction is highly efficient in generating a vortex.

Spectrum of Gyrotropic Modes and Energy Transfer between Dipolar‐Coupled Magnetic Vortices in a Square Lattice via Triggered Vortex Gyration: A Promise for Spintronics Technology

AbstractThe atoms in a crystal lattice vibrate together and generate vibrational modes known as acoustic and optical phonon modes. Similarly, collective vortex gyration motion can be generated in artificial magnetic vortex lattices, created from periodically arranged nanodisks of specific dimensions and aspect ratios. This study uses micromagnetic simulations to characterize the spectra of gyrotropic modes in two‐dimensional magnetic vortex‐based, tailor‐made square lattice arrangements. The shifting of mode frequencies and mode splitting is witnessed depending on the vortex configurations in the lattice. The obtained gyrotropic modes are analogous to two‐dimensional square lattice structures exhibiting acoustic and optical phonon modes. The dynamics of magnetic vortices are also discussed in the transfer of magnetic energy at three points along the three high symmetry directions of the lattice when the central magnetic vortex is excited by a spin‐polarized current with an excitation frequency equal to the collective gyrotropic frequencies of the vortices. Similar to the higher contribution of acoustic phonon modes in the heat transmission process in a crystal lattice, acoustic‐like gyrotropic modes transfer more energy than optical‐like gyration modes in the vortex lattices. These magnetic metastructures hold promise for novel applications in magnetic waveguides and information processing devices, as well as for advancing spintronics.

Performance of solar vortex engine integrated with the PV panel: Experimental assessment

Solar energy is one of the most important options for humanity to face the danger of energy depletion and to address the problem of environmental pollution resulting from the use of fossil fuels. The primary goal of the current article study is to present a new design of a Solar Vortex Engine system integrated with a photovoltaic panel. System implementation and analysis were approached and discussed. The system consists of a 3.0 m2 solar collector inclined with a 36° and a cylindrical vortex generator engine with an outer diameter of 40 cm and a height of 30 cm.The outcomes showed that the developed solar vortex engine could generate a circular updraft with the ratio of the tangent to the axial velocity of 2.83 m/s in the upper exit plane of the vortex generation engine. The electrical efficiency of the system containing a horizontal solar panel was higher than that of the system containing a vertical solar panel and reach its highest value of 14% at 10 a.m. Also, the highest thermal efficiency values were 45% for the system without a solar panel. The results confirmed that the presence of solar panels causes a clear decrease in the thermal efficiency of the system. The proposed solar vortex engine design presented and tested in this article is convenient for forming an artificial upward vortex.

An implementation of the SPH method and its application to two-dimensional dam break cases

A basic implementation of the weakly compressible smoothed particle hydrodynamics (W-SPH) method is used to model the open surface flow phenomena of two different types of hydraulic problems. They were both two-dimensional approximations of known hydraulics problems: dam break over dry bed and dam break over wet bed with shallow and deep variants. For all models, the results were compared quantitatively with data from waterfront profiles from previously published experiments. A qualitative approach was used to assess the general profile shape comparing the numerical hydraulic profile results with published photographs of all setups shown. The numerical model converged to a stable solution with relatively low-resolution setups (2 000 to 20 000 particles) and a good correlation was found with the experimental and numerical references, even without the application of correction algorithms. Numerical oscillations in the density field did produce small artificial waves and vortices, but did not interfere with the behavior of the bulk of the fluid except for some delay in the speed of surface waves. The choice of developing an entirely original, self-contained source code, although very insightful, does mean that the neighboring particle search algorithm used considerably increments the associated computational cost. However, using this insight along with the basis of the comparison with experimental results, optimization priorities for the source code were found and some guidelines to choose fluid resolution and boundary density can be applied for future cases where the flow phenomena are similar to those studied. Also, the experience of writing the SPH source code that was used to solve the numerical models, shows the path for future developments on fluid flow modeling using this method.

A Design and Analysis of Artificial Vortex (ArVo) Based Stand-Alone Microgrid on Universities of Bangladesh

The administration of universities of Bangladesh faces financial drawbacks every year due to subsidies in the field of electrical power cost. The reason behind this is, students, consume more electric power than they pay for. To solve this problem a modern hydroelectric technology can be implemented. This new technology is called Artificial Vortex (ArVo). This method of power generation utilizes the natural tendency of whirlpool formation of fluids by defining a new flow path thereby causing a turbulent circular movement of fluid layers. Every day students and teachers use a huge volume of water. This water is excluded from the university premises by the wastewater paths. This wastewater flow can be utilized to generate electricity. In Artificial Vortex, a curved wall is designed in the water path to concentrate the water flow and generate rotational energy. This rotational energy is implemented on a vertical axis turbine. This turbine is rotated by the water flow impact and produce clean electricity through an alternator. The cost of electricity has been simulated by HOMER Pro software.

Realization and experimentation of a novel vortex cooling tower

The vortex generation motor is a new energy concept for creating artificial vortex and air flow. This paper describes an experimental study of a new vortex tower design carried out at the Birine Nuclear Research Centre in Algeria; this is the first upward vortex tower prototype built in Algeria to evaluate such technology. This work is part of a project to study and conception a prototype of a vortex tower to produce electrical energy using the heat from the nuclear reactor secondary system instead of dissipating it into the atmosphere. The study started by the design and the construction of the vortex tower prototype at a reduced scale (1/5), for applying it later to a full scale in a Nuclear Power Plant. The measurements of temperatures, air velocity, humidity and pressures at several locations inside the prototype were effectuated, as well as the estimation of the installation power output. The analysis of the test results shows that the realized vortex tower can generate an air flow and that the kinematic energy field is significant, where the velocity maximum value reached equal to 7.7 m/s with an average velocity of 2.5 m/s. In addition, this configuration has a potential for production of the electrical energy where the average and maximum power output of this tower were calculated and estimated to be 3.896 W and 113.849 W respectively. Moreover, the results demonstrated that the bladed-shaped inlets in the convergence chamber have a significant effect on vortex generation and flow acceleration in the chimney. Improvement of the performance of this model at real scale contributes to a country's energy production and will help to minimize the environment thermal pollution.

Pengujian Turbin Air Pusaran Gravitasi dengan Variasi Overlap Ratio Rotor

The gravitational water vortex turbine is a turbine system that can convert the energy from artificial water vortex by means of the drained water through the basin outlet to the kinetic energy of rotor rotation. This type of turbine system is able to produce energy despite the low head of water flow. Many researches were conducted to improve the efficiency of this turbine by changing the shape of basin, or the rotor. Meanwhile, the Savonius rotor has good starting rotation and ease of fabrication, but low efficiency. One way to increase the efficiency of this rotor is to apply the gap between the blades which is called Overlap Ratio (OR). In this research, the gravitational water vortex turbine with the conical-shape basin was combined with the various-OR Savonius rotors with area proportion of 26,88% and without endplate and the effect was observed to the efficiency of turbine. The volume flowrate of channel was maintained constant at 0,005 m 3 /s while mass was added gradually for the torque measurement system by using rope brake dynamometer. The result showed that for all rotors, the greater efficiency occurred in the low rotational speed. Moreover, the rotor with OR of 0,15 had greater mechanical efficiency which was around 22,78% for the rotor with endplate 26,88% and 27,18% for the rotor without endplate than rotor with OR of 0. Meanwhile, rotor without endplate had higher maximum mechanical efficiency for all OR variation than that with endplate 26,88%.

Study of Vortex Systems as a Method to Weakening the Urban Heat Islands within the Financial District in Large Cities

This paper presents a new concept called the urban vortex system (UVS). The UVS couples a vortex generator (V.G.) that produces updraft by artificial vortex and a vortex stability zone (VSZ) consisting of an assembly of four buildings acting as a chimney. Through this system, a stable, upward vortex flow can be generated. The Reynolds Averaged Navier–Stokes (RANS) simulation was carried out to investigate the flow field in the UVS. The Renormalized Group (RNG) k–ε turbulent model was selected to solve the complex turbulent flow. Validation of the numerical results was achieved by making a comparison with the large-size experimental model. The results reported that a steady-state vortex could be formed when a vapor-air mixture at 2 m/s and 450 K enters the vortex generator. This vortex presented a maximum negative central pressure of −6.81 Pa and a maximum velocity of 5.47 (m/s). Finally, the similarity method found four dimensionless parameters, which allowed all the flow characteristics to be transported on a large scale. The proposed large-scale UVS application is predicted to be capable, with have a maximum power of 2 M.W., a specific work of 3 kJ/kg, buildings 200-m high, and the ability to generate winds of 6.1 m/s (20 km/h) at 200 m up to winds of 1.5 m/s (5 km/h) at 400 m. These winds would cause the rupture of the gas capsule of the heat island phenomenon. Therefore, the city would balance its temperature with that of the surrounding rural areas.

Mechanisms of SWBLI control by using a surface arc plasma actuator array

Mechanisms for controlling the shock wave boundary layer interaction (SWBLI) by a plasma actuator array are investigated by two experiments. Low-frequency and high-frequency actuation modes are compared. The experimental results yield valuable insights into the control mechanism of SWBLI using a surface arc plasma actuator array. The schlieren snapshots and the mean and root mean square error of the image sequence and pressure measurements are analyzed to determine the control mechanisms. The high-frame schlieren images for flow visualization indicate a significant modification of the separation shock in both experiments due to thermal injection. More importantly, because the high-frequency actuation mode operates at relatively low energy, it can provide quasi-continuous perturbations, providing stable control for separation shock weakening. The Iband/Itotal ratio for low-frequency unsteadiness obtained from the pressure spectrum is reduced below 5% at 10 kHz forcing. The integrated schlieren intensity IRMS and power spectrum indicate a dominant vortex forcing effect as an additional actuation mechanism in addition to the gas heating effect that may affect the separation shock and its interaction with the boundary layer. As the plasma actuation is activated, numerous periodic streamwise vortices and small-scale trailing vortices are produced in the high-frequency actuation mode, resulting in an enhancement of the mixture upstream of the interaction region and promoting the momentum transfer to the boundary layer. In addition, the large-scale turbulence structures characterized by low-frequency unsteadiness are subject to artificial vortex shedding by the plasma perturbation, further increasing the momentum transfer in the boundary layer. We propose a conceptual model describing the vortical activity due to actuation and the interaction between plasma actuation and the SWBLI flow. Thus, a hybrid mechanism of SWBLI control associated with vortical activity exists.

A New Method for Analyzing Aero-Optical Effects with Transient Simulation

Aero-optical effects reduce the accuracy of optical sensors on high-speed aircraft. Current research usually focuses on light refraction caused by large-scale density structures in turbulence. A method for analyzing photon energy scattering caused by micro-scale structures is proposed in this paper, which can explain the macro image distortion caused by moving molecules in inhomogeneous airflow. Quantitative analysis of the propagation equation indicates that micro-scale structures may contribute more to the wavefront distortion than the widely considered large-scale structures. To analyze the micro mechanism of aero-optical effects, a transient simulator is designed based on the scaling model of transient distorted wavefronts and the artificial vortex structure. The simulation results demonstrate that correct aero-optical phenomena can be obtained from the micro mechanism of photon energy scattering. Examples of using the transient simulator to optimize the parameters of the star sensor on a hypersonic vehicle are provided. The proposed analysis method for micro-scale structures provides a new idea for studying the aero-optical effects.

Design and Experimental Characterization of an Indoor-Scale Artificial Updraft Vortex Power Generator

An indoor-scale experimental model of artificial vortex power generator has been designed and tested. The model consists of four main components which are collector, tower, guide walls, and heating system. The collector and tower are constructed from poly-methyl methacrylate material. Both collector and tower are translucent allowing flow visualization experiments with laser and smoke to be performed for experimental characterization. The experimental model converts the supplied thermal energy into kinetic energy in form of updraft vortex airflow. Magnitude of the artificial updraft vortex is measured using a fan installed at the center of the tower. Rotational speed of the fan is measured by using a high-speed camera. The results show that the experimental model capable to rotate the fan up to 200 rpm.

Performance evaluation of solar vortex engine and optimization of number of air entry slots and turbine location

ABSTRACT Solar vortex engine (SVE) is one of the novel alternative energy concepts which uses solar energy for creating artificial vortices. The working principle of SVE is the same as the solar updraft tower (SUT) plant. In the present study, a 3D computational model of SVE was studied to evaluate the flow parameters and power potential. The effect of the number of air entry slots (AESs) which is varied from 6 to 12 and the location of the turbine were studied and optimized. A turbulent, renormalization group (RNG) k-ɛ model was used to solve the governing equations. The flow parameters such as velocity, temperature and dynamic pressure for the optimum SVE with 8 AESs were 1.42 ms−1, 311.1 K and 1.58 Pa, respectively. The optimum height for the turbine was 0.702 m from the base plate (0.1 m from the top plate) and so that the turbine can harness maximum energy. The theoretical and actual powers for the optimum case (AESs of 8 and the turbine at 0.702 m) were 3.45 and 2.3 W, respectively. The study proved that SVE is a potential choice to replace the chimney of a solar updraft tower (SUT) plant for electricity generation.

Estimation of flow parameters and power potential of solar vortex engine (SVE) by varying its geometrical configurations: A numerical study

Solar vortex engine (SVE) is a novel concept for creating artificial vortices and airflow using solar energy. The working principle of SVE is similar to the solar updraft tower (SUT) plant, but SVE replaces the chimney of SUT plant. SVE consists of air entry slots (AES), guide blades and top and base plates having an outlet and base holes, respectively. In the present study, a 3D model of SVE with an external bounding structure (EBS) was developed to evaluate the flow parameters and visualize the flow and vortex generation inside the domain. The flow parameters were estimated by varying the top-hole diameter (0.2–0.5 m) and increasing inlet velocity at AES (0.2–0.7 m/s). The increase in top hole diameter from 0.2 to 0.5 m, flow parameters enhanced significantly and reached a maximum at 0.3 m and after it decreased. Higher inlet air velocity at AES enhanced flow parameters significantly. The optimum height was 0.702 m from base plate (0.1 m from the top plate) as it had the maximum velocity of 4.4 m/s and vorticity of 73.9 s−1, so that a turbine can be fixed at this location to harness maximum energy. The average velocity, temperature, dynamic pressure, theoretical and actual powers of SVE with EBS for optimum case (top hole diameter of 0.3 m, inlet velocity at AES of 0.7 m/s) were 1.4 m/s, 311.1 K, 1.6 Pa, 3.5 and 2.3 W, respectively. The preliminary study results shown that, SVE is one of the potential options to replace the chimney of SUT plant for generating electric power.

A novel solution method for unsteady incompressible Euler flow using the vorticity–Bernoulli-pressure formulation

A novel numerical formulation and time-integration method for the incompressible Euler flow equations is presented using the vorticity–Bernoulli-pressure system. Lagrangian advection of vorticity-carrying particles is adopted from classical vortex methods that are known to give accurate results for vortex-dominated flows and allow larger time steps than explicit Eulerian schemes. Solving only one scalar Poisson equation per time step instead of a vector-valued equation in vortex methods makes the new scheme theoretically more efficient on large computational grids. The equation of motion in rotation form is integrated in time under certain approximation assumptions and solved explicitly for the flow velocity. The velocity is eliminated as an unknown in the continuity equation, which is efficiently solved for the Bernoulli pressure using the predicted vorticity field obtained by Lagrangian advection. The Bernoulli pressure is efficiently obtained from the Poisson equation in finite volume formulation. An estimated velocity field is calculated from the equation of motion. To effectively counterbalance the discretization errors made by the prediction, in a corrector step the kinematic relation between vorticity and estimated velocity is reformulated and solved in a Lagrangian framework as well. The velocity field is corrected at the end of the time step. Two-dimensional cases on Cartesian grids are considered. Numerical results for three flow cases demonstrate the locally smooth and accurate behavior and the second-order spatial accuracy of the solution. The new scheme produces significantly less artificial vortex distortion than the classical vortex method. The favorable properties of the solutions with respect to accuracy and long-time stability of the overall kinetic energy and enstrophy are also emphasized.

Control of nanostructure and pinning properties in solution deposited YBa2Cu3O7\u2212x nanocomposites with preformed perovskite nanoparticles

Solution deposited YBa2Cu3O7−x (YBCO) nanocomposites with preformed nanoparticles represent a promising cost-effective approach for superior critical current properties under applied magnetic fields. Nonetheless, the majority of YBCO nanocomposites with high nanoparticle loads (>20%) suffer from nanoparticle coalescence and degraded superconducting properties. Here, we study the influence of nanoparticle concentration (0–25% mol), size (5 nm–10 nm) and composition (BaHfO3, BaZrO3) on the generation of structural defects in the epitaxial YBCO matrix, key parameter for vortex pinning. We demonstrate that flash-heated superconducting nanocomposites with 20 mol% preformed BaHfO3 or BaZrO3 perovskite secondary phases feature discrete and small (7 nm) nanoparticles and high density of YBa2Cu4O8 (Y248) intergrowths. We identify a synergy between Y248 intergrowth density and small nanoparticles to increase artificial vortex pinning centers. Also, we validate the multideposition process to successfully increase film thickness of epitaxial nanocomposites with competitive critical currents Ic at 77 K.

A Review of CFD Investigations on Heat Transfer Augmentation of Forced Convection Solar Air Heater through Enhanced Fluid Turbulence Levels

Solar air heaters generally exhibit lower levels of thermal performance due to higher heat losses and poor heat transfer characteristics of air which is the working fluid. Many investigations, both experimental and numerical, have been carried out in the past to overcome these limitations. One of the commonly used techniques for thermal performance enhancement in solar air heaters is to enhance the turbulence levels in the flowing air stream. This paper presents a detailed review of investigations involving numerical studies for thermal performance enhancement of solar air heater by enhancing turbulence levels in the air flow. It is observed that the focus of numerical simulation studies has been on the use of artificial roughness elements, corrugations and vortex generators to achieve higher turbulence levels in the air flow. RNG k-e turbulence model has been commonly used to capture the turbulent flow characteristics. An attempt has also been made to summarize the operating parameters and heat transfer enhancement parameters of various numerical simulation studies done in the past with respect to turbulence enhancement technique

Влияние вдува малоразмерных струй различных конфигураций на структуру и акустическое излучение сверхзвуковой струи

The work is devoted to experimental study of the structure and acoustic radiation of a supersonic underexpanded jet Ma = 1, Npr = 5 with the presence of vortexgenerators in the form of small-sized jets injections. Ten different configurations were tested, in which following the gas-dynamic and geometrical parameters of the microjets were changed one by one: microjets pressure, the injection distance from the main nozzle section, azimuthal, tangential, and axial angles of micronozzles inclination. The flow visualization, azimuthal Pitot pressure profiles and characteristics of jet noise in the far field were obtained. It has been revealed that the injection of microjets in general leads to an increase in the jet long-range and a decrease in its mixing. The advantageous parameters of the microjets injection for reducing the jet acoustic emission are the injection point vicinity to the main nozzle section, micronozzles inclination to main jet axis and the small tangential angle of micronozzles. The micronozzles quantity effect is non-linearly in relation to the structure and the jet noise. The average pressure measuring distribution near artificial longitudinal vortices in a jet stream cannot predict the characteristics of its mixing and acoustic radiation.

Zirconium distribution in solution-derived BaZrO3 - YBa2Cu3O7-δ epitaxial thin films studied by X-ray photoelectron spectroscopy

Superconducting YBa2Cu3O7-δ films with different amounts of BaZrO3 nanoinclusions were deposited on SrTiO3(001) by low-fluorine chemical solution deposition with the aim of introducing artificial vortex pinning centres. The Zr concentration over the film thickness could be determined by X-ray photoelectron spectroscopy combined with Ar+ ion etching. The Zr/Y ratio has a constant behaviour in the film's bulk. Zr segregation occurs near the surface and Zr diffusion into the substrate is observed near the interface. Conversely, Sr and Ti from the substrate diffuse into the films. Y3d lineshape analysis and X-Ray Diffraction data pointed out that Ti diffusion causes the formation of Y-Ti-O based spurious phases.

Water vortex hydropower technology: a state-of-the-art review of developmental trends

With the explosive growth of global energy demand coupled with effects of climate change, there is a significant shift towards green energy generation in recent years. Of the various renewable energy resources available, micro-hydro-power and pico-hydro-power remain very popular in both developed and developing countries. Since 2006, significant growth has spurted in the use of artificial free-surface vortices to generate low and ultra-low-head hydropower following the development of the so-called gravitational water vortex hydropower plant. The technology works on the principle of harnessing hydroelectric power from the high angular velocity experienced in the core of a whirlpool generated in a vortex chamber. In this article, a state-of-the-art review is undertaken on the vortex hydropower technology including a historical review of the technology, the underlying hydraulic principles of such devices, overview of research and technologies that have been deployed to date together with an evaluation of their performance and key findings. Currently, there are 19–22 known live vortex hydropower technologies operating internationally with key academic and commercial research activity in Europe and Asia. The average efficiency from these sites was found to be in the region of 53% which is lower than conventional propeller turbines but higher than waterwheel systems. It was found that the vortex plant, due to its ability to sustain relatively high efficiencies at low heads and small to medium flow rates, addresses a gap in the current turbine application chart. Its key advantage lies in the high-power densities produced compared with conventional technologies. The system also demonstrates potential to be able to function as a fish passage; however, stronger validation is required to prove this for a range of turbine systems. Finally, the authors propose a number of areas that should be investigated that should provide immediate improvements to the turbine in terms of performance.

Tunable artificial vortex ice in nanostructured superconductors with a frustrated kagome lattice of paired antidots

Theoretical proposals for spin ice analogs based on nanostructured superconductors have suggested larger flexibility for probing the effects of fluctuations and disorder than in the magnetic systems. In this work, we unveil the particularities of a vortex ice system by direct observation of the vortex distribution in a kagome lattice of paired antidots using scanning Hall probe microscopy. The theoretically suggested vortex ice distribution, lacking long range order, is observed at half matching field (H_{1}/2). Moreover, the vortex ice state formed by the pinned vortices is still preserved at 2H_{1}/3. This unexpected result is attributed to the introduction of interstitial vortices at these magnetic field values. Although the interstitial vortices increase the number of possible vortex configurations, it is clearly shown that the vortex ice state observed at 2H_{1}/3 is less prone to defects than at $H_{1}/2$. In addition, the non-monotonic variations of the vortex ice quality on the lattice spacing indicates that a highly ordered vortex ice state cannot be attained by simply reducing the lattice spacing. The optimal design to observe defect free vortex ice is discussed based on the experimental statistics. The direct observations of a tunable vortex ice state provides new opportunities to explore the order-disorder transition in artificial ice systems.