Jerry
44 lines
2.0 KiB
Markdown
44 lines
2.0 KiB
Markdown
# 8. Centrifugal Impeller With Backward-Curved Blades
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## Prompt
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Create a single solid centrifugal impeller as a STEP model in millimeters.
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The impeller axis is vertical along Z and centered at the origin.
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Add a circular backplate disk with outside diameter 90 mm and thickness 6 mm, with its bottom face at Z = 0.
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Add a central hub cylinder on top of the backplate, diameter 26 mm and height 22 mm above the backplate.
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Add a vertical through-bore of diameter 8 mm through the entire part.
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Add 12 identical backward-curved blades on top of the backplate, equally spaced around the hub. Each blade begins at radius 18 mm and ends at radius 43 mm. Each blade is 3 mm thick, 16 mm tall above the backplate, and curves backward by approximately 45 degrees from root to tip. The blade tips should lean opposite the direction of rotation when viewed from above.
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Add 1 mm fillets at the blade roots where they meet the backplate and hub. Add a 1.5 mm fillet to the top and bottom outer circular edges of the backplate.
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Export as a STEP file.
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## Test Cases
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| Test | Expected result |
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| --- | --- |
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| STEP import | File imports successfully |
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| Solid count | One fused watertight solid |
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| Backplate diameter | Diameter 90 mm |
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| Backplate thickness | 6 mm |
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| Hub diameter | Diameter 26 mm |
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| Hub height | 22 mm above backplate |
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| Through-bore | Diameter 8 mm through entire part |
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| Coaxiality | Backplate, hub, and bore share Z-axis |
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| Blade count | 12 |
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| Blade spacing | 30 degrees between adjacent blades |
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| Blade radial span | Approximately R18 to R43 |
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| Blade height | 16 mm above backplate |
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| Blade thickness | Approximately 3 mm |
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| Blade curvature | Approximately 45 degrees backward from root to tip |
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| Blade fusion | Blades joined to backplate and hub |
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| Fillets | 1 mm blade-root fillets; 1.5 mm backplate edge fillets |
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| Negative check | No straight radial-only blades unless curvature requirement is otherwise approximated; no floating blades |
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