The Grid Independence of an Electric Vehicle Charging Station with Solar and Storage

The UK government has set a ban on the sale of new petrol and diesel cars and vans by 2030. This will create a shift to electric vehicles. which will present a substantial impact on the grid. Therefore, methods to reduce the charging station’s impact on the grid have to be developed. This paper’s objective is to evaluate how integrating solar and storage affects a charging station’s dependence on the grid. A photovoltaic electric vehicle charging station (PVEVCS) is first designed, and then four charging profiles are selected to assess the station through a simulation using MATLAB. The array produces 3257 MWh/yr which, on average, offsets 40% of the electric vehicle (EV) load experienced by the station. Furthermore, with the integration of storage, the dependence is further reduced by 10% on average. The system also exported energy to the grid, offsetting close to all the energy imported.

Multiple Slip and Inspiration Effects on Hydromagnetic Casson Fluid in a Channel with Stretchable Walls

Increasingly innovatory techniques are being developed for the manufacturer of coated sheets. Magnetite non-Newtonian fluids have been shown to exhibit stretchable wall slip, which arises due to non-adherence of the non-Newtonian fluid to the boundary. Motivated by the physical nature of the magnetic non-Newtonian fluid in manufacturing transport phenomena, we develop a model to analyze the collective influence of velocity and thermal slips, radiative heat flux effects on fluid and heat transport phenomena in magnetic non-Newtonian fluid flow in a channel with stretchable walls. Governing equations are non-dimensionalized and solved numerically. Grid independence test has been performed and then compared with existing literature in limiting cases. Results are discussed with the aid of graphs for the sway of several physical parameters, Casson parameter, Magnetic parameter, Thermal radiation parameter on fluid velocity, as well as temperature profiles for different cases: No-slip, only first-order slip, and first and second-order slips.

Artificial diffusion in the simulation of micromixers: A review

False (artificial) diffusion provides an erroneous estimation of molecular diffusion during the simulation of liquid micromixing. The present review introduces discretization methods, numerical grid types, and numerical errors to address the effect of false diffusion on the prediction of mixing efficiency of microfluidic devices. False diffusivity is characterized by the grid Peclet number, grid type, and discretization scheme. This review demonstrates that most investigators have selected a grid resolution just for the grid independence test. It is revealed that the convergence criterion should not be quantitative values of mixing efficiency even when high-order schemes are employed to discretize the computational grid. Based on the previous publications in this field, a straightforward procedure is recommended to manage false diffusion in the numerical simulation of micromixers.

Improvement of Grid Independence Test for Computational Fluid Dynamics Model of Building Based on Grid Resolution

Computational fluid dynamics (CFD) is being used in various research fields on the building environment. Target space of the CFD model is divided into a finite number of grids for numerical analysis. Therefore, an optimal grid design is required to obtain accurate results. The grid independence test is generally performed to design an optimal grid. However, given that there is no standardized procedure for gird independence test, most depend on the researcher’s experience and knowledge. In the conventional method, the subjective judgment of the researcher affected the selection of the grid conditions and the criteria for the optimal grid. It can lead to a decrease in the reliability of the simulation results by poor grid design. This study proposed a grid independence test method that applies the grid resolution to improve the conventional method. The grid resolution was calculated by applying the characteristic length. CV(RMSE) and R2 were applied as the criteria for optimal grid. A case study was conducted to evaluate the adequacy of the proposed method. As the characteristic length increased, the optimal grid resolution increased. In particular, for a characteristic length of 0.7 or more, the optimal grid resolution was evaluated as 24. The grid convergence index (GCI) was calculated to verify the suitability of the proposed method. As a result, all of the optimal grid resolution derived from the proposed method was evaluated as the optimal condition.

Numerical Simulation Study on Battery-Casing Sealing Considering Rubber Aging

ABSTRACTBattery-casing sealing is the key factor for secure travel of new energy vehicles. We constructed a relatively accurate mechanical-simulation model by selecting a constitutive model, analyzing the influence of thermal elongation, verifying the grid-independence and comparing numerically by the pressure-measurement film on the basis of studying the physical performance of a certain type of sealing material that had been used in battery-casings after aging. Based on a porous-media model and combined with changes of macroscopic and microscopic contact characteristics of materials at different times after aging, the evolution rule of sealing performance with time was analyzed quantitatively by calculating the leakage. By analyzing the structure of circular arc bulge on the surface of sealing material, the radius of circular arc bulge with better sealing performance was obtained, which could reduce the leakage of sealing structure during the material’s lifecycle.

CFD NUMERICAL SIMULATION OF TEMPERATURE AND AIRFLOW DISTRIBUTION IN PIGSTY BASED ON GRID INDEPENDENCE VERIFICATION

Grid independence verification was implemented to improve the reliability of CFD numerical simulation in pigsty. The effects of four different grid numbers on airflow and temperature simulation of 0.4m, 1.0m and 1.6m heights were compared. The results showed that the third method of mesh generation and the grid numbers about 2.09 million were more suitable for this pigsty model. The average relative error of airflow velocity and temperature between the simulated and the measured alues were 7.1% and 3.8% respectively, the average NMSE were 0.0012 and 0.0066 respectively. Therefore, grid independence verification is of great significance for CFD numerical simulation.

Survey of 8 UAV Set-Covering Algorithms for Terrain Photogrammetry

Remote sensing with unmanned aerial vehicles (UAVs) facilitates photogrammetry for environmental and infrastructural monitoring. Models are created with less computational cost by reducing the number of photos required. Optimal camera locations for reducing the number of photos needed for structure-from-motion (SfM) are determined through eight mathematical set-covering algorithms as constrained by solve time. The algorithms examined are: traditional greedy, reverse greedy, carousel greedy (CG), linear programming, particle swarm optimization, simulated annealing, genetic, and ant colony optimization. Coverage and solve time are investigated for these algorithms. CG is the best method for choosing optimal camera locations as it balances number of photos required and time required to calculate camera positions as shown through an analysis similar to a Pareto Front. CG obtains a statistically significant 3.2 fewer cameras per modeled area than base greedy algorithm while requiring just one additional order of magnitude of solve time. For comparison, linear programming is capable of fewer cameras than base greedy but takes at least three orders of magnitude longer to solve. A grid independence study serves as a sensitivity analysis of the CG algorithms α (iteration number) and β (percentage to be recalculated) parameters that adjust traditional greedy heuristics, and a case study at the Rock Canyon collection dike in Provo, UT, USA, compares the results of all eight algorithms and the uniqueness (in terms of percentage comparisons based on location/angle metadata and qualitative visual comparison) of each selected set. Though this specific study uses SfM, the principles could apply to other instruments such as multi-spectral cameras or aerial LiDAR.

A Study on the Effect of Angle in Diffused Hole Film Cooling Effectiveness at Different Blowing Ratios

Higher the turbine inlet temperature of a gas turbine, higher will be the efficiency, however the increase in the turbine inlet temperature is limited to the materials and the cooling strategies employed. This article presents a study on the effect of blowing ratio on film cooling effectiveness for a cylindrical hole and a diffused hole at different angles. The analysis was done for blowing ratios of 0.5, 1.0, 1.5 and 2.0 while the angle in the diffused hole was varied as 5°, 10° and 15°. A grid independence study was performed and the simulation was validated. The results of cylindrical and different angles of diffused holes were compared. For a cylindrical hole as well as diffused hole, a blowing ratio of 1.0 was found to have an optimal effectiveness. The diffused hole was found to improve the near hole and downstream effectiveness at higher blowing ratios.

THE EFFECT OF BLADE PROFILE ON THE PERFORMANCE OF A SIDE CHANNEL PUMP

This article presents the results of a numerical modeling of a steady turbulent flow of an incompressible fluid in an open-type vortex pump with an open side channel, comparing the generalized simulation results with the existing experimental data. The mathematical model is based on the Reynolds-averaged Navier — Stokes and continuity equations, as well as on the equations of the two-layer Realizable k-ε turbulence model that accounts for the curvature of streamlines. The authors have estimated the grid independence of the solution and studied the influence of 14 blade profiles on the head and efficiency of the vortex pump. The solution of the model equations was achieved by the finite volume method using a sequential algorithm in three calculation areas (“feeder channel”, “blade wheel”, “open hull side channel and diverter channel”) with the evaluation of grid independence of the solution. The result of the solution between the calculated areas was transmitted at the corresponding points of the interface surfaces. The authors have studied the influence of 14 profiles of a blade on pressure and efficiency of the vortex pump: the initial profile of the blade with the installation in the wheel coaxial shaft of the ring plate of different width, the initial profile of the blade with a bevel on the discharge side, a profile in the form of an isosceles triangle, a profile in the form of a quadrangle, the initial profile with a rounded blade on the suction side, and a profile in the form of a rectangular triangle with a rounded blade on the suction side, among others. The simulation results have aided in proposing the blade profiles: in the form of a rectangle with a convex rounding of the blade on the suction side with a 10 mm radius and a right-angled triangle with a concave rounding of the blade on the suction side with a 52 mm radius and without rounding, giving a significant increase in pressure — more than 20%. Nevertheless, none of the considered cases have revealed any significant increase in the vortex pump hydraulic efficiency.