In order to improve the aerodynamic performance of a gas turbine exhaust volute

a collectionshell type volute was numerically studied and the source of flow losses was presented. Based on that

a flow separation layer design was put forward without changing the geometry size of the exhaust volute

and the comparisons of the effects between this design and two common methods were carried out. The numerical simulation results show that the flow separation layer design can at most decrease the total pressure loss coefficient by 3212% and increase the static pressure recovery coefficient by 48.73% on the design point; this is better than the result of adjusting arc lines of the diffusing structure

but worse than that of the wall profile modification of the collector. Accordingly

the mechanism of how the separation layer can improve the aerodynamic performance of the volute was revealed.