Performance characteristics of an axial‐flow gas induction impeller

Abstract

AbstractPower number, pressure coefficient, and induced gas flow rate of a novel axial‐flow gas induction impeller with large openings for gas flow are reported. The effects of rotational speed, impeller diameter, submergence, and pumping mode are considered in turbulent operation. The pressure coefficient is measured using the reduction in pressure at speeds below the minimum induction speed as well as from the minimum induction speed. The minimum induction speed approach consistently yields lower pressure coefficient values, indicating the existence of impeller exit losses that are required to force gas from the centre of the impeller into the liquid. The induced gas flow rate is modelled using two approaches. The first approach relates the gas flow rate to the available pressure difference, and in this case, the relation is found to be strongly affected by impeller diameter. The second approach is a literature model that likens the induction process to water jet injection. While this approach appears promising, flow measurement device pressure losses make it difficult to definitively evaluate this method.