Hydraulic tests of a new centrifugal pump with shrouded impeller for extracorporeal membrane oxygenation systems

Abstract

BACKGROUND: The problem of creating a centrifugal pump for extracorporeal membrane oxygenation systems (hereinafter referred to as ECMO), optimal in terms of its hydraulic characteristics and its effect on blood, still remains relevant. This work is a continuation of the authors’ previous research in this area and contains the results of hydraulic tests of prototypes of the new ECMO pump with the closed impeller on water and water-glycerin mixtures, which imitate the viscous properties of blood. AIM: Determination and comparison the head-flow characteristics of the new ECMO pump with the closed impeller when operating on water and water-glycerin mixtures. METHODS: A series of hydraulic tests of pump prototypes, manufactured using different technologies, was carried out. Three liquids were considered as the working fluid during the tests: process water at a temperature of 20 °C and two water-glycerin mixtures at a temperature of 20 °C with different ratios of water and glycerin (to obtain different viscosities). RESULTS: The pressure characteristics of pump prototypes, manufactured using different technologies, were obtained using water and water-glycerin mixtures. Tests with use of water showed that the deviation of the calculated and experimental characteristics from each other does not exceed 4%; the deviation of the characteristics of prototypes, manufactured using different technologies, is on average 1.5%. Tests with use of a water-glycerin mixture showed that the deviation of the characteristics from those obtained with use of water is on average 6%, the largest deviation is observed at the edges of the characteristics. In addition, when tested with use of a water-glycerin mixture, the deviation of the characteristics of prototypes, manufactures using different technologies, is about 4%, which is higher than when tested with use of water. CONCLUSION: The results obtained allow us to conclude that the numerical model used in previous work can reliably predict the performance of the pump with use of water. The pressure characteristics of water and a water-glycerin mixture differ from each other, which must be taken into account when assessing the operating parameters of such pumps. The influence of manufacturing technology on the performance characteristics of the pump is higher when it operates with use of a liquid more viscous than water, e.g. on a water-glycerin mixture.