Optimization of Non-Circular Void Concrete Extruder

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Braga, Mateus
Penner, David
Zheng, Qiuhao
Au-Yeung, Lap
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Ultra-Span, an industry leader in circular void concrete extruders is currently developing a non-circular void (NCV) concrete extruder. The current NCV design produces uneven concrete slabs and its extrusion speed is slow. Due to uneven compaction, the extruded concrete slabs are experiencing concrete starvation at the two top edges of the slab and the NCV extruder is also extruding at half the speed of its circular void counterpart (30 [in/min] versus 60 [in/min]). The team at World Wide Convergence (WWC) undertook the project to optimize Ultra-Span’s NCV concrete extruder. WWC’s objectives for this project were to research other concrete extruders, develop concepts that improve the quality of the concrete slabs produced, increase the extrusion speed, evaluate the concepts using Computational Fluid Dynamics (CDF), and suggest an optimized final design. WWC served as CFD specialists to model the concrete flow within the extruder. The required deliverables included CFD analysis, detailed design optimization, 3D models of the optimized final design, a poster of the final design, and a final design report. Prototyping, physical testing, manufacturing, a bill of materials, and a cost summary were excluded from the scope. Following an engineering design methodology 15 concepts were developed. After evaluating the performance of the concepts in compatibility for manufacture, minimal number of parts, pressure performance, viscosity performance, flow uniformity, and maintenance/cleaning ease, 11 concepts were eliminated in a screening process. The four concepts chosen for additional evaluation were to alternate the direction of rotation between the five augers, increase the length and close off the gaps between material shields, attach vanes on top of the mandrels, and add vanes to the sidewalls of the extruder cassette. Once the four concepts were evaluated using CFD a weighted decision matrix was used to select the advancing concepts. The advancing concepts were to alternate the direction of rotation between the five augers and increase the material shield length. These two designs were then combined in a final design optimization phase. The final design developed by WWC integrates perfectly into Ultra-Span’s existing NCV extruder with no additional components or new procedures. The simple yet effective final design […]