2.2.8. Impeller–Case Distance *sd*

The impeller–case distance was evaluated following an analysis carried out on the geometric characteristics of the pumps under examination. An average value of 9 mm was established. Although there are undeniable differences between this value and the real one, the influence of the parameter on the evaluation of quantities of interest, and in particular the friction efficiency on the disc, is reduced to such an extent that the approximation was deemed acceptable.
