Modeling and Simulation Study of a Novel Bat Sand Vertical Axial-Wind Turbine

A wind turbine with a vertical axis offers a high potential for energy production. Numerous operational and design aspects, such as aspect ratio, blade number, climatic conditions, dust effect, rain impact, humidity, and other geometrical forms, affect the performance of vertical axial-wind turbines. In this work, CFD was used to analyze the flow characteristics across the blades of a unique vertical-axis wind turbine. The tests were conducted at various airflow velocities, including 2 m/s, 4 m/s, 6 m/s, and 8 m/s. Utilizing numerical simulation, the pressure contours and streamlines were drawn. Due to the direct influence of the dynamic pressure on the front surface of the turbine blades, the highest pressure was observed on the front side of the blades. Maximum vortices were found on the rear side of the turbine blades, whilst minimal vortices were observed on the front side. Likewise, the lowest pressure was measured on the side of the turbine blades. At airflow velocities of 8 m/s and 2 m/s, the highest and minimum pressure values measured were 7.3 kPa and 2.63 kPa, respectively. Additionally, streamlines were identified.


INTRODUCTION
Due to fossil fuels such as coal, natural gas, and furnace oil, environmental consequences and energy accessibility have lately become major problems for engineers and academics.In 2030, the global population is projected to surpass 8.2 billion. 1 Where environmental concerns are paramount, renewable energy is typically the superior energy source.To assist meet the world's energy demands and minimize emissions, several researchers are investigating alternative renewable energy sources.Wind, solar, and tidal energy are emission-free and cost-effective renewable sources of electricity.Consequently, among the various renewable energy sources, wind energy has grown increasingly prevalent in recent years. 2 Beyhaghi et al. investigated the effect of a slot bored into the leading edge of the airfoil span on the aerodynamic performance of wind turbines.On the lift and drag coefficient, they also examined the influence of factors such as blade thickness, inlet angle, and the vertical section of the slot attacked at various angles.Using numerical modeling, this study enhanced the lift coefficient by up to 30 percent, while the drag was sacrificed somewhat. 3,4aqas et al. evaluated statistically the impact of hot ambient conditions on savories-type VAWTs with varying speed ratios and blade angles.Consequently, the results demonstrated that temperature variations negatively impact the performance behavior of wind turbines. 5sing the high-order Delay Detach-Eddy Simulation (DDES) model, Dessoky et al. simulated and modeled the VAWT to analyze the performance and noise mechanism of the VAWT and discovered that the leading edge of the blade was responsible for the noise.In order to anticipate the aeroacoustic and aerodynamic performance of VAWT, they compared their findings with unstable Reynolds Averaged Navier-Stokes models. 6alduzzi et al. conducted a 3-D Navier-Stokes CFD simulation to evaluate the unsteady aerodynamics of Darrieustype VAWT rotor blades.They discovered that the threedimensional flow of Darrieus VAWT varied dramatically during rotor revolution and indicated the merits and shortcomings of the reduced dependability model for constructing Darrieus turbines. 7amed Allhibi et al. studied ten years of wind data to determine the viability of wind energy generation in various Saudi Arabian locales.In addition, they proposed the many prospective sites in Saudi Arabia that are most suited for wind energy generation, as well as wind turbine specs.Several places in Saudi Arabia were also found to be optimal for wind energy production, and the Saudi government can take the initiative to construct and establish a number of wind farms through pilot projects.In addition, the study indicated that utilizing a renewable energy resource, such as wind power generation, can be advantageous for generating 20% of its electrical power. 8assan Al Garni et al. suggested a multicriteria decisionmaking strategy based on an analytical hierarchy method in order to assess Saudi Arabia's five renewable power generation systems.Such as concentrated photovoltaic, wind, biomass, and geothermal power generating systems. 9bdullah Al-Sharafi et al. investigated the viability of a solar and wind-powered power generating system in many Saudi Arabian locations, including Dhahran, Riyadh, Jeddah, Abha, and Yanbu.In addition, they noted the various Ali M. Eltamaly et al. developed a foolproof method for determining the optimal location and wind turbines for these sites based on the lowest cost per kilowatt-hour generated by a wind power system.In addition, they built a brand-new computer software that performed all the necessary calculations and optimization for the construction of a wind energy generating system and compared various sites and wind turbines. 10,11okheimer et al. designed and simulated an integrated hybrid wind turbine and solar energy system.These simulation findings were utilized to design the system for the lowest cost per cubic meter of desalinated water.In Dhahran, Saudi Arabia, they also conducted a performance analysis of a hybrid wind turbine linked with the solar system. 12akbul A.M. Ramli et al. examined the feasibility of a hybrid wind-solar power generating system in the coastal region of Saudi Arabia.They examined the energy production and cost of a hybrid energy producing system.Additionally, unmet electrical load and extra power were taken into account.The yearly average solar radiation and wind velocity in the coastal region of Saudi Arabia were determined to be 5.95 kWh/m 2 and 3.53 m/s, respectively.Alternatively, they utilized MATLAB and HOMER software to conduct the technical and economic study of the hybrid wind turbine system. 13The aim of this novelty design is to design and model a bat-shaped wind turbine to produce an electricity and work as a mechanical sand baffle.

METHODOLOGY
In this study, the 3D CFD analysis of the bat type wind turbine was performed at different flow velocities in order to examine the flow characteristics over the wind turbine.The 3D model of the bat type turbine unit was generated by using AUTODESK and then imported into fluid flow simulation and make a computational domain.Figure 1 shows the schematic diagram of the novelty bat-shaped turbine design.The flow analysis was analyzed and plotted to show the pressure distribution, the velocity distribution and the vortex streamlines.The boundary conditions were employed, as shown in the table 1 and 3D unstructured meshing (Tetrahedral meshing) was generated in order to get stable and accurate.The total number of elements and nodes for this model were 14361 and 17592, respectively.

THE STANDARD K -Ε MODEL
The K-ɛ was employed which is a semi-empirical model as the equation for the eddy dissipation rate (Chen and Kim, 1987).The two equations, for unsteady compressible flows, are: is the turbulence production and is expressed as follows: is the buoyancy effect and is expressed as follows: is a correction for compressible flows and is expressed as follows: The equation of the dynamic eddy viscosity is given by: All constants in equation ( 1) are given as follows: , , , and .

RESULTS AND DISCUSSIONS
The 3D-CFD model analysis was undertaken in order to evaluate the performance of the bat axial-wind turbine design for varying sand-wind speeds.The analysis was conducted to examine the pressure and velocity distributions, as well as the vertices.On the frontal surface of the turbine blades, the greatest measured pressure was achieved at 8 m/s and the minimum measured pressure was obtained at 2 m/s.As seen in Figures 2 and 3, the maximum observed pressure and vertices emerge mostly in the wake region as sand velocity increases.It can be noted that the vertices were formed on the rear side of the turbine blades, while the highest pressure was detected on the front side.In Figure 4 , the difference between the normalized velocity in the near wake region and the experimental data 14 was greater than 18% in the near wake region, however the velocity grows closer to the experimental date as one moves away from the wake region.

CONCLUSIONS
The 3D-CFD-K-model has been run at various wind speeds: 2, 4, 6, and 8 meters per second.As simulation tools, Autodesk drawing software and fluid flow software were utilized in this investigation.In addition, the frontal surface of the bat wind turbine blades revealed the maximum and minimum pressure profiles.It has a maximum pressure of around 72.8 kPa at 8 m/s wind speed.In addition, the velocity distribution was measured and compared with the findings of a different simulation model (k-ɛ) and the actual data, revealing a strong agreement.Thus, the bat axialwind turbine may be used to generate electricity from a sand -wave speed in a desert and as a sand buffer.

Fig. 4 .
Fig. 4. The validation of the normalized velocity along the streamwise direction at the hub -height the bat axial-wind turbine for the selected domain Modeling and Simulation Study of a Novel Bat Sand Vertical Axial-Wind Turbine Yanbu Journal of Engineering and Science