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► VOLUTE | Cut-water
The geometry of the cut-water can be designed in this dialog box.
Generally, the cut-water can be designed in three modes: Simple, Fillet or Sharp.
The leading/trailing edge axis ratio specifies the ratio between the minor and major axis length of an ellipse, representing the leading and trailing edge of the splitter.
General |
The wrap angle must be at least 330°. |
Simple |
For cornered spiral cross sections the side position is fixed to the corner position and cannot be modified individually. |
Rounding of cut-water edges (Round edges) is possible only if side position is higher than the position of maximum curvature and if no radial offset is defined. |
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Radial offset is available for strictly external volutes with 360° wrap angle only. |
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Fillet |
Fillet cut-water is not available for cornered cross sections, either spiral or diffuser. |
Intersection of spiral and diffuser geometry is necessary to create a fillet cut-water. |
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Fillet cut-water is usually not possible, if the spiral development is at the beginning very flat and a tangential diffuser with a big end cross-section is chosen. |
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For asymmetric spiral cross sections, only non-tangential surface transition is available. |
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Sharp |
Sharp cut-water is not available for cornered cross sections, either spiral or diffuser. |
Intersection of spiral and diffuser geometry is necessary to create a sharp cut-water. |
Problem |
Possible solutions |
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Intersection of Side A1/B1 with Inlet/Outlet |
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Cut-water Side A1/B1 face intersects with Inlet/Outlet face. Inlet/Outlet is a virtual face bordering the Volutes's Flow domain. The intersection affects volumetric meshing of the Flow domain, which may result in very small mesh entities and in a non smooth surface in these regions. Generally, the intersection is very small and hardly visible in 3D-model. |
Any parameter modification of the Fillet Cut-water affects the geometry of the side patches. Use automatic Surface transition. |
Cutwater is self-intersecting. |
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Cut-water faces intersect each other. |
The problem might have various reasons. Therefore, modify spiral, diffuser or cutwater design. E.g. define a flat radius progression at the start of spiral development areas, or change angular position / radial offset of the cutwater. |
Multiple intersection curves between spiral and diffuser. |
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Spiral and diffuser may have multiple intersection curves. (red) |
This problem can be solved by manipulating the spiral start position. A single intersection curve is required for generation of sharp and fillet cut-waters. |
3D-Error: Could not create bounded surface for Cut-water! |
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Parameter side position is disadvantageous. |
The side position should not be too low when edges are rounded. |
3D-Error: Could not create fillet for Cut-water! Possibly, the fillet radius is too large. |
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[for asymmetric volutes] Fillet cannot be created because intersection curve of spiral and diffuser is wavy. |
Modify the Position of end shape in the Diffuser dialog to avoid wavy intersection curve. |
[for asymmetric volutes] Fillet cannot be created because intersection curve of spiral and diffuser is tangential to the sharp diffuser edge. |
Modify Spiral start position
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