Research On Aerodynamic Drag Reduction Of GTS Model Based On Plasma Flow Control

As a means of production,fuel consumption of commercial vehicle is one of the important indexes to evaluate the comprehensive performance of the vehicle.As an active flow control method,plasma flow control has many advantages,such as light weight,high reliability,low cost and fast response.Therefore,it is of great significance to study the flow control effect of plasma on vans and put forward a feasible aerodynamic drag reduction scheme for commercial vehicles.In this paper,the aerodynamic drag reduction effect of plasma flow control on GTS model is investigated by CFD simulation and the computational fluid dynamics software Fluent is used.The main research contents are as follows:Firstly,the 3d cavity model is used for plasma numerical simulation,and the simulation results are compared with existing experimental data to verify the accuracy of the simulation method in this paper.Then plasma flow control effect is applied to the cylindrical model.The control mechanism of plasma flow is revealed by comparing the aerodynamic resistance coefficient,vorticity diagram and shear stress cloud diagram of the cylinder before and after plasma excitation.Besides,the aerodynamic drag reduction of cylindrical turbulence by plasma flow control is studied,the results show that,the mechanism of plasma flow control is to push the separation point of the upper and lower surface of the cylinder backward by inducing the directional movement of the near-wall gas.Thus,the size and intensity of turbulent region at the tail of cylindrical turbulence are reduced.And the aerodynamic drag coefficient of the cylinder is reduced by reducing the pressure differential resistance between the front and rear of the cylinder.When the wind speed of the incoming flow is constant,the plasma has the best excitation position and excitation voltage.The wake field of cylindrical turbulence can be smoothed effectively with proper excitation voltage and placement,so as to reduce the aerodynamic resistance coefficient of the cylinder.With the increase of the inlet wind speed,the plasma flow control effect is weakened.Secondly,three positions plasma to be applied are selected based on outflow field information of GTS model.The effect of plasma excitation position,excitation voltage on local flow control of GTS model and the influence of different inlet flow wind speed on the plasma control effect at three locations are investigated.Deepen the plasma flow control mechanism,supplemented by the plasma power effect and fuel consumption savings comparison.Simulation results show that,due to the large area of negative pressure at the rear of the GTS model,proper round inversion treatment can significantly reduce the aerodynamic resistance coefficient of the vehicle,and is conducive to the arrangement of the plasma actuator and change its excitation Angle.When the plasma is generated by dielectric barrier discharge,the current is small and the energy consumption is small.When the excitation position and voltage of the plasma are adjusted appropriately,the energy savings brought by the aerodynamic drag reduction of the plasma are far greater than the energy consumption.The flow control mechanism of plasma on GTS model is to delay the flow separation,make the flow separation point move backward,reduce the size of the negative pressure area at the rear of the body,reduce the pressure difference between front and rear of the body,and thus reduce the aerodynamic resistance coefficient of the vehicle.The plasma excitation has the best excitation position and excitation voltage.And that effect decreases when increase the wind speed of the incoming flow.Finally,the optimal aerodynamic drag reduction conditions of plasma at each position are combined to explore the aerodynamic drag reduction of GTS model vehicle by plasma flow control under the combination conditions of individual incoming flow wind speed.Simulation results show that,under each inlet wind speed,the aerodynamic drag reduction effect of the combined conditions at three positions is the optimal condition.With the increase of the inlet flow wind speed,the aerodynamic resistance coefficient of GTS model generally shows a downward trend,but the aerodynamic drag reduction rate gradually decreases,so it can be seen that the plasma flow control effect weakens with the increase of the inlet flow wind speed.When the wind speed of the coming flow is 15m/s and the plasma is applied for the three positions,the aerodynamic drag reduction effect of GTS model vehicle is the best.The aerodynamic drag coefficient of GTS model is 0.4265 and the aerodynamic drag reduction rate is 6.16%.