Study On A Passive Vortex Vane For Vehicle Air Intake System

Throttle body is one of the most important components in vehicle intake system.Driver controls its opening, then control the flow rate of the intake air, so steer thevehicle according to the driver’s intentions. At present, the throttle valve is a singlecircular chip. So it can not effectively guide the airflow to form vortex at small opening,and it can not mix air and fuel evenly on the small and medium load. It results in lowerfuel efficiency, poor emissions, large vibration and other issues. In this thesis, a kind ofpassive vortex vane is designed, which can be utilized in automotive air intake pipe.Swirl ratio is substantial enhanced at the expense of small flow rate loss in commonopening range of the throttle valve. Therefore, this study has a very important practicalvalue.In this thesis, a simplify geometry model has established for a specific type ofthrottle body. According to the diversion effect of vane, a geometry model of passivevortex vane is designed, which matched the throttle body. Based on the standard k-εmodel and RNG k-ε model of FLUENT software, the simulations show that the standardk-ε model has higher calculation accuracy in the flow field simulation of throttle body by comparingwith bench test. The path line, velocity field, pressure field and the turbulence intensitydistribution of the flow field are analyzed. A performance evaluation method for thesimulation of the airway is established, which reference to FEV evaluation method ofbench test. Calculation formulas of coefficient ratio and vortex ratio are derived, andcorresponding Matlab computing program is given. Based on the standard k-ε model ofFLUENT software, the influences of the bending angle, vane number and vane width ofthe passive vortex vane on the flow coefficient and swirl ratio of the throttle body aresimulated. The effects of vortex vane on flow coefficient and swirl ratio aresynthetically considered, and three optimized vortex vanes are elected, which structuralparameters are very close. The influences of No.Ⅰvortex vane to the characteristics offlow field are analyzed in detail, including traces, velocity field, pressure field and theturbulence intensity distribution, and so on. Bench tests have been done for throttlebody and No.Ⅰvortex vane on throttle body on the comprehensive performance teststand S7802. Experimental results and simulation results are consistent.Finally, real vehicle tests are done for these three optimized passive vortex vanes,and driving performances are evaluated by subjective evaluation, which based on expert evaluation method. The results show that all of the three optimized passive vortex vanescan improve the driving performances significantly. But the No.Ⅱ vortex vane is best,which vane number is6, width is8.5mm, bending angle is40°. Correctness andeffectiveness of the passive vortex vane designed in this thesis are verified bysignificantly improved subjective driving performances.