Study on the Efficiency and Dynamic Characteristics of an Energy Harvester Based on Flexible Structure Galloping

According to the engineering phenomenon of the galloping of ice-coated transmission lines at certain wind speeds, this paper proposes a novel type of energy harvester based on the galloping of a flexible structure. It uses the tension generated by the galloping structure to cause periodic strain on the piezoelectric cantilever beam, which is highly efficient for converting wind energy into electricity. On this basis, a physical model of fluid–structure interaction is established, and the Reynolds-averaged Navier–Stokes equation and SST K -ω turbulent model based on ANSYS Fluent are used to carry out a two-dimensional steady computational fluid dynamics (CFD) numerical simulation. First, the CFD technology under different grid densities and time steps is verified. CFD numerical simulation technology is used to simulate the physical model of the energy harvester, and the effect of wind speed on the lateral displacement and aerodynamic force of the flexible structure is analyzed. In addition, this paper also carries out a parameterized study on the influence of the harvester’s behavior, through the wind tunnel test, focusing on the voltage and electric power output efficiency. The harvester has a maximum output power of 119.7 μW/mm3 at the optimal resistance value of 200 KΩ at a wind speed of 10 m/s. The research results provide certain guidance for the design of a high-efficiency harvester with a square aerodynamic shape and a flexible bluff body.

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.