In order to improve the static pressure recovery of specific low speed wind tunnel wide angle diffuser(WAD) and reduce the total pressure loss to the level of the splitter plates

different configurations of WAD were studied using computational fluid dynamics (CFD). The screens could restrain flow separation. The position and opening area ratio of the screens had an important effect on the flow regimes and total pressure loss. The total pressure loss using linear wall WAD was greater than the expected value. Due to the oversize diffuser angle

the first screen played a little role on separation control of WAD inlet. By use of cubic curve wall

the total pressure loss evidently decreased and was less than the expected value. But a little separation in WAD existed. Simple segment linear walls had profound function on the drop of total pressure loss. Based on the method of maximum static pressure recovery

WAD using three segment linear walls was designed. The separation of inlet disappeared. And the total pressure loss was reduced to a great extent. Further investigation on the diffuser of three segment linear walls indicated that the angle of the first level diffuser was upper limit to the edge of separation based on the method of maximum static pressure recovery. To restrain separation of the third level diffuser

the method was reasonable to shorten the second level diffuser length and reduce the third level diffuser angle. Combination of satisfactory parameters

which could significantly produce less total pressure loss to the expected level

was obtained based on flow regime analysis of different configurations. It is concluded that the optimal design of WAD can be obtained based on numerical simulation.