In: Mechanical Engineering
GEOMETRIC DESIGNOF CENTRIFUGAL IMPELLER:
1) Definition and determination of geometric parameters:
In this the parametric design method is adopted and geometric parameters are defined according to the working principle of professional type five axis control machine tools.
2) Construction of impeller geometry:
The hub shroud contours in th pressure side and suction side are modified in order to control the cross section relative veloocity in the blade passage.
3) Generating machining method:
The surface of the blade can be described as the machining swpt surface which is used as a ruled surface of the tool track created by the generated machining method.Once the machining method is determined ,
the three dimensional contour surface of the impeller could be described as an offset surface shifted from the swept surface by a distance equal to the radius of the tool.In the machining of the twisty blade surface the offset process is adopted to assure the preciseness of blade contours.
4) Numerical simulation:
For performance calculations only the flow passage between the two blades including the inlet and outlet extensins is defined as the computational domain.which is generated by the three dimensioal hexahedral structure grid.