Chemical engineering calculations to assist process, plant operation and maintenance engineers.
In series arrangement, each pump handles same flow rate, but the total head produced by the combination of pumps will be additive. Since each pump generates a head H corresponding to a flow Q, when connected in series, the total head developed is Ht = H1 + H2, where H1, H2 are the heads developed by the pump in series at the common flow rate Q.
With pumps in parallel, the flow rates are additive with a common head. The flowrate Qt is split between the inlet into Q1 and Q2. Each pump develops the same head H at the corresponding capacity. Thus, the first pump at capacity Q1 develops the same head H as the second pump at capacity Q2.
The efficiency curve of two or more identical pumps in series or parallel will be the same as each individual pump.