Investigating the impact of multi-piped impellers design on the efficiency of rotodynamic pumps operating at ultra-low specific speed

Multi-piped impellers (name proposed by the author) represent an innovative approach to the design of rotodynamic pumps operating at the specific speed of nq < 10. In such a construction the energy increase is caused by the flow of liquid through the internal impeller passages as well as by an external flow around the passages, and sensible designing of such a construction is extremely difficult. The study investigates the impact of the basic construction parameters of a multi-pipe impeller on the efficiency of the process of energy transfer into liquid. The main research method involves computational fluid dynamics (CFD) simulations. The selected impeller constructions are made with the SLS (rapid prototyping) method and tested with a measurement stand. The paper presents the comparison of numerical and experimental results. Based on the obtained results the author makes recommendations on the construction of multi-piped impellers.