PERFORMANCE ENHANCEMENT IN DISCHARGE MEASUREMENT BY COMPOUND BROAD CRESTED WEIR WITH ADDITIVE MANUFACTURING.

Manufacturing compound weirs for exact discharge measurement has been a challenge, according to studies so far. The length of the weir crest (L), weir height, and weir width all affect the efficacy of compound broad crested weirs as flow monitoring devices. As a result, the flow characteristics of a given flume are determined by changes in weir geometry, particularly the discharge coefficient (Cd), which varies proportionally with the h/L ratio. For varying h/L levels, many researchers have maintained an average range of Cd. The experimental and Computational Fluid Dynamics simulations for measuring discharge by compound broad crested weir are presented in this work. Validation in the results is achieved using CFD FLOW 3D software. For enhanced accuracy in free surface simulations, the model uses the renormalized group (RNG) approach with the volume of fluid (VOF) method. Laboratory models were employed in an attempt to analyse and validate the CFD model. The model is fabricated using PVC material first and later resorted to additive manufacturing for targeting accurate discharges. The shape of the compound broad crested weir was modified to achieve constant Cd by comparing three-dimensional computational fluid dynamics models to experimental measurements. The performance of the CBC weir for precise measurement of a wide range of discharges is confirmed by numerical simulations and experimental measurements, with a reasonably constant design input value of discharge coefficient of 0.6. When compared to empirical methods, CFD-based weir geometry optimization produces more exact model predictions. Moreover, manufacturing this optimized model with 3D printing technology using Poly Lactic Acid plastic material has validated the weir performance with accurate estimates between theoretical, experimental and CFD outputs. [ABSTRACT FROM AUTHOR]

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