What shape is the case of a regenerative turbine?

The case of a regenerative turbine is typically round in shape. This design is essential for several reasons. First, a round case allows for uniform flow patterns, minimizing turbulence and promoting efficient fluid dynamics within the turbine. The circular geometry helps distribute the pressure evenly around the impeller, thereby optimizing the energy transfer from the impeller to the fluid.

Moreover, the round shape facilitates the manufacture and assembly of turbine components, which are often rounded as well, such as the impellers and volutes. This consistency in geometry contributes to reducing stress concentrations and enhancing the overall structural integrity of the turbine case.

The other options, such as square, rectangular, or hexagonal shapes, do not provide the same advantages in terms of fluid flow efficiency and structural harmony that a round case does. These shapes may introduce corners and edges that can disrupt smooth fluid flow, leading to inefficiencies and potential cavitation, which would negatively affect the turbine's performance.