At Mach numbers ranging form 0 2 to 0 35

two schemes 1/5th scale models of exhaust diffusers and elbow exhausts have been researched.The first scheme was a diffuser with wide cone angle.In order to reduce the separation losses

the concentric splitter cones were set to augment the diffusibility.The splitter cones were made by subdividing the short wide angle diffuser into a series of smaller

more optimal ones.The second scheme was a diffuser with smalle r cone angle

in order to reduce the length

the diffuser ratio was distributed between the linear diffuser and the turning vane to improve the overall performence.The results of the model test show that total pressure re covery coefficient C P of the second scheme is rather high and the pressure loss coefficient ΔP/Q 1 is reduced.At the same time

the ΔP/Q 1 of different constructions of the first scheme were measured separately

and the measurements were analysed.The function of the splitter cones was demonstrated.Se veral test curves were used to prove the certain effect of the pre swirl cascade in some diffuser angle ranging.Therefrom the beneficial design ideas are obtained.