Experimental Study And Numerical Simulation Of Flow Field In Counter-rotating Fan

In this paper, aerodynamic performance, noise situation of conter-rotating fan is researched under different gap. The internal flow field has been tested and two types diffuser has been calculated.Two major studies of fan's performance is following.Frist testing is performance between differfent gap,it presentes that,if the axial gap is 55% of frist hub length,the fan has a well performance of pressure,Second,rotating velocity is tested to validate its effect on performance, frequency conversion is used to change electromotor's speed,it indicate its possible to use conform-low on conter-rotating fan.The result of noise experiment point out when the fan workes on its rating working situation,the noise is decreased as the length of the gap,when the fan workes on its little flow situation,it performes bounty frequency ,the noise isn't affect by the gap's length.The flow field of fan is tested by the five-hole probe,the distributing of velocity and pressure is tested,which containes axial angle,axial velocity, radial velocity and static pressure,total pressure.The date of flow field on great flow situation,little flow situation,highest efficiency situation is tested.Two usual type diffuser is simulated in the last part,both different working simulation and theory method is done.From the rusult, its efficiency is changed with the working condition,to the same equal taper,when it uses the taper inside cylinder outside,the diffuser has a better performance.