Aerodynamics of Tandem Stators II

Modern gas turbines have to meet the highest requirements in terms of environmental compatibility and economic efficiency. Reducing specific fuel consumption is of central importance and can be achieved by increasing the pressure build-up per stage. Another possibility is to reduce the number of blades within a stage. Both approaches increase the aerodynamic load on the compressor blades.

Conventional compressor blades are thus pushed to the limit. Due to the large positive pressure gradient in the rear area of the blade, the boundary layer grows strongly, the flow can no longer follow the profile contour and detaches. A high increase in losses and a collapse of the pressure build-up are the result. Tandem blades can provide a remedy here. On tandem blades, the flow at the rear blade is re-energised by the resulting slot flow and a new, thinner boundary layer is formed.