Modeling Pipe Networks Dominated by Junctions

Abstract

The transfer of energy and irreversible energy losses at junctions may dominate flow distribution in pipe networks comprised of connected large‐diameter pipes of short lengths. Neglecting the junction effects when calculating network hydraulics is unacceptable and the use of constant loss coefficients to represent these effects in such networks may not be adequate. In the present study, precise relationships based on experimental data are used to represent the junction‐loss coefficients. These relations, which depend on flow conditions, are incorporated into a computer network analysis model. Significant deviations in flow rates calculated using constant junction loss coefficients and the semiempirical relationships based on experimental data are obtained using an example network characterized by short pipe sections. It is also shown that although there is always a net energy loss at a junction, there may be significant exchange of specific energy from one flow stream to the other. The use of constant loss coefficients is inadequate to account for this phenomenon.