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► IMPELLER | Meridional contour
The design of the meridional contour is the second important step to design the impeller.
Meridional design is divided in 3 parts:
•Primary flow path
This contains the design of the primary flow path. Necessary for the following design steps.
•Hub/ Shroud solids (optionally)
This contains the design of hub and/or shroud solids. This is an optional part focusing on stress analysis.
•Secondary flow path (optionally)
This contains the design the secondary flow path behind hub and/or shroud. This is an optional part focusing on detailed flow analysis.
Problem |
Possible solution |
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Inlet hub diameter: deviations between Meridional Contour |
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The difference between the hub diameter and the corresponding geometric size in the meridian is too large. This is possible for imported polylines only. |
Adjust either the main dimensions or the imported curve. |
Inlet shroud diameter: deviations between Meridional countours |
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The difference between the suction diameter and the corresponding geometric size in the meridian is too large. This is possible for imported polylines only. |
Adjust either the main dimensions or the imported curve. |
Outlet diameter: deviations between Meridional Contour |
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The difference between the impeller diameter and the corresponding geometric size in the meridian is too large. This is possible for imported polylines only. |
Adjust either the main dimensions or the imported curve. |
Outlet width: deviations between Meridional Contour |
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The difference between the outlet width and the corresponding geometric size in the meridian is too large. This is possible for imported polylines only. |
Adjust either the main dimensions or the imported curve. |
Hub/ Shroud contour has discontinuities inside blade region. |
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The hub resp. shroud contour is divided into sub-curves who are not connected smoothly in blade region. |
Adjust hub resp. shroud contour and apply smoothness at connectors who are inside blade region. |
Angle between hub/ shroud contour and inlet/ outlet is not recommended. |
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The current angle between hub/shroud contour and inlet/outlet can cause problems in Model finishing. |
Manipulate hub/shroud contour or move inlet/outlet to change the current angle to inlet/outlet.
Contour may contain extremely small and unnecessary parts which should be removed. |
Hub contour intermittently touching z-axis (r=0) is not supported. |
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The hub curve is touching the z-axis internally. Before and behind it the radius is greater than 0 creating a complete constriction. |
Avoid hub regions at r = 0 internally |
Meridional contour has an invalid topology. (inside out) |
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The sense of circulation of the closed wire containing the inlet, shroud, outlet and hub curve in this specific order is counter-clockwise. |
Manipulate meridional curves to guarantee a clockwise sense of circulation or adjust inlet and outlet in main dimensions. |