Abstract: Concentrated wind energy device is the core component of concentrated wind energy turbine, and its structure determines output power of the wind turbine.To enhance the efficiency of the concentrated wind energy turbine, a geometry model and mesh model were built by the three-dimensional modeling software and CFD (computational fluid dynamics) software with the concentrated wind energy device as the research object.Based on the model, the feasibility of the numerical simulation method applied in this study was verified by adopting the vehicle-mounted method.The van carrying the model could produce the natural wind field with different flow velocity by running along a straight road with different speeds.When the speed of the van was adjusted properly, the flow speed of the produced natural wind field was 10 m/s.The total pressure(Pt) and static pressure (Ps) at different axial and radial points inside the model without impeller and generator were measured by pitot tube and digital pressure gauge.The simulation and experiment results of the flow velocity variation trends at each test point were roughly the same.So the conclusion could be made that the simulation model is reliable and results are credible.Based on the CFD software analysis of the fluid field, the wind flow was simulated in a specific wind field.The fluid medium was the air with temperature of 296.75 K.The velocity-inlet and pressure-outlet were adopted.The inlet velocity was set to 10 m/s and the gauge pressure of the outlet was set to 0 Pa.Other boundaries were set as stationary wall and no slip.Then the research was performed to research the influence of different turbulence models on the internal flow field.These four kinds of turbulence models were Spalart-Allmaras model, Standard κ-ε model, Standard κ-ω model and Reynolds Stress Model (RSM).According to the calculation results, we could get the radial and axial velocity distribution of concentrated wind energy device in different turbulence models.In the Spalart-Allmaras model and Standard κ-ε model, the inlet velocity and outlet velocity were roughly the same, which did not accord with the actual situation of the device.And in the RSM, the flow velocity near the wall appeared unstable and fluctuating, which did not match the experiment results either.However, in the Standard κ-ω model, the flow velocity in the diffuser changed slightly.Therefore, we can conclude that Standard κ-ω model is more suitable for the internal flow field simulation of concentrated wind energy device than other models.Based on the above mesh model and turbulence model, internal flow field characteristics of concentrated wind energy devices were simulated and analyzed with different dimensional parameters.The results showed that when the reducer angle was 80°and the inlet diameter was 1272 mm, the internal flow field had the maximum velocity of 26.10 m/s, and the rate of velocity increase was 8.98%.When the diffuser angle was 80°and diffuser length was 322 mm, the maximum velocity of internal flow field was 26.16 m/s, and the rate of velocity increase was 9.23%.When the central cylinder length was 297 mm, the maximum velocity was 24.91 m/s, and the rate of velocity increase was 4.0%.Therefore, a pattern could be summarized that the diffuser angle has greater influence than reducer angle and central cylinder length.At last, the internal flow field of an optimized model was simulated under different inflow wind speeds to analyze the influence of inflow wind speed on the internal flow field.The results showed that there was a linear relationship between the maximum velocity of the flow field and inflow wind speed.And it could be concluded that the concentrated wind energy device has the advantage of high concentration efficiency.All the results and conclusions can provide a basis for the structure optimization of concentrated wind energy device, and the optimized structure can significantly improve the quality of wind energy and output power of wind turbines.