Head coefficient
The head coefficient (ψ) is a characteristic coefficient, derived from the corresponding physical quantity according to the affinity laws and used to characterise the operating behaviour. It characterises the head (H) of the pump:
When the head varies at constant rotational pump speed, ψ ~ H. The head coefficient (ψ) is therefore indicative of the ordinate (analogous to H) on H/Q curves plotted in a non-dimensional representation. In conjunction with the specific energy (Y) this results in:
