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Experimental Testing and Modeling Analysis of Solute Mixing at Water Distribution Pipe Junctions
Citation:
Shao, Y., J. Yang, L. Jiang, T. Yu, AND C. Shen. Experimental Testing and Modeling Analysis of Solute Mixing at Water Distribution Pipe Junctions. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 56:133-147, (2014).
Impact/Purpose:
This journal article is to inform public of most updated research results on drinking water distribution system modeling and controls.
Description:
Flow dynamics at a pipe junction controls particle trajectories, solute mixing and concentrations in downstream pipes. Here we have categorized pipe junctions into five hydraulic types, for which flow distribution factors and analytical equations for describing the solute mixing behavior are proposed. First, based on experiments, the degree of mixing at a cross is found to be a function of flow momentum ratio that defines a junction flow distribution pattern and the degree of departure from complete mixing. Corresponding analytical solutions are also validated using computational-fluid-dynamics (CFD) simulations. Second, the analytical mixing model is further extended to double-Tee junctions and the flow distribution factor is modified to account for the difference giving arise from hydraulic departure from a cross configuration. For a double-Tee(A) junction, CFD simulations show that the solute mixing depends on and connection pipe length whereas the mixing at double-Tee(B) is well represented by two independent single-Tee junctions with a potential water stagnation zone in between. It is found that double-Tee junctions differ significantly from a cross in solute mixing and transport; however, these pipe connections are commonly simplified as cross junctions of assumed complete solute mixing in network skeletonization and water quality modeling. Based on the results, we consider the proposed junction mixing model and analytical equations can make it possible to accurately calculate solute concentrations at pipe junctions and hence improve water quality simulation of a distribution network.
