Combining junction losses on channel sections in ventilation duct system flow analyses

When the airflow pressure losses at the junctions of ducts in ventilation systems are taken into account, the analysis becomes more complicated since no unique value for the static pressure is associated with a junction. Additional system equations expressing the pressure jumps over the junctions must be written down. A method to replace the junction losses approximately as equivalent channel section losses is presented. The method is based on dissipation considerations. Simpler system equations with fewer unknowns are obtained. Some example cases are presented to give an idea about the errors involved.