What is a swirl?
Most pumps are based on the principle of rotation. If an object rotates around a rotational axis, it is referred to as angular momentum – that is, the movement of the object around the rotational axis, the swirl.
Swirl in pumps – how it affects the characteristic
Swirl is important during the operation of pumps in various ways. One example is the change of the swirl of the pumped medium, which can be used purposefully for controlling the pump characteristic. The swirl of the pumped medium changes between entering and exiting the impeller. This also changes the characteristic for the head and the operating energy input.
Change of swirl by using swirl control
A swirl control allows changing the swirl of the inflow to the impeller. It can generate a counter-swirl and thereby increase head and operating energy input. On the other hand, the two variables decrease with increasing co-swirl.