The optimization of the blade surface velocity distribution is promising for a reduction of turbine cascade losses. Theoretical and experimental investigations on three turbine cascades with the same blade loading show the important influence of the blade pressure gradient and the free-stream turbulence on the loss behavior. The results presented demonstrate that it is the boundary layer transition behavior that determines the losses on turbine cascades. An enormous effort in measuring technique is required in order to define the location of transition from cascade experiments very accurately.

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The optimization of the blade surface velocity distribution is promising a reduction of turbine cascade losses. Theoretical and experimental investigations on three turbine cascades with the same blade loading show the important influence of the blade pressure gradient and the free stream turbulence on the loss behaviour. The results presented demonstrate that it is the boundary layer transition behaviour that determines the losses on turbine cascades. An enormous effort in measuring technique is required in order to define the location of transition from cascade experiments very accurately.

The paper presents two-dimensional cascade results which have been obtained in transonic and supersonic cascade windtunnels. The upstream Mach number range is 1,0 ≤ M1 ≤ 1,4. Tests have been carried out with three different blade shapes; these are double-circular-arc and wedge profiles. The influence of solidity on the performance of these cascades has been investigated. A detailed analysis and calculation of the shock losses shows the great influence of profile shape on the total pressure loss coefficient. The profile losses are roughly constant in the investigated Mach number range. In addition, some measurements for different back pressures are presented. These results are analyzed with the aid of a simple calculation, which shows that the axial velocity-density ratio has to be considered as an important parameter in supersonic cascade measurements.

In this paper the supersonic exit flow field of a two-dimensional cascade is described. Different flow configurations at axial subsonic and supersonic velocities are discussed in detail and calculation methods are presented. The range of possible cascade operation and its dependency of back pressure is evaluated. It is shown that the exit flow field of a double infinite cascade can be simulated behind a semi-infinite cascade.