What is the effect of piping two pumps with the same flow capacity and pressure rating in series?

When two pumps with the same flow capacity and pressure rating are piped in series, the primary effect is the increase in the total head developed by the pump system. The term "head" refers to the height of water that a pump can raise, and when pumps are arranged in series, their individual heads add together. This means that if each pump can develop a certain amount of head, the combined system will be able to produce a total head that is approximately double that of a single pump (assuming ideal conditions and no significant losses).

It is important to note that while the flow rate remains constant (the same as the flow capacity of the individual pumps), the pressure can be affected in other configurations, but in the case of series arrangement, it effectively allows for overcoming higher pressure conditions or elevating water to greater heights. Efficiency losses might occur due to increased friction losses and potential turbulence in the system with two pumps, but the primary function of series pumping is to enhance head, making the scenario of "double the head" the most relevant outcome.