MODELING PIPE NETWORKS DOMINATED BY JUNCTIONS

The transfer of energy and irreversible energy losses at junctions may dominate flow distribution in pipe networks comprised of connected pi pes of short lengths. Neglecting the junction effects when calculating network hydraulics is unacceptable and the use of constant loss coeff icients to represent these effects in such networks may not be adequat e. In the present study, precise relationships based on experimental d ata are used to represent the junction-loss coefficients. These relati ons, which depend on flow conditions. arc incorporated into a computer network analysis model. Significant deviations in flow rates calculat ed using constant junction loss coefficients and the semiempirical rel ationships based on experimental data are obtained using an example ne twork characterized by short pipe sections. It is also shown that alth ough there is always a net energy loss at a junction, there may be sig nificant exchange of specific energy from one flow stream to the other . The use of constant loss coefficients is inadequate to account for t his phenomenon.