Influence of Blade Number on Performance and Internal Flow Condition of Centrifugal Pump for Low Viscous Fluid Food

摘要

There are many kinds of the fluid food transportation pumps depending on the characteristics of the fluid, i.e. a sanitary pump made from stainless steel, a screw pump and so on. A centrifugal pump was adopted as a fluid food pump in this research because it makes the stable continuous transportation of fluid food and the structure of the pump is simple compared to positive displacement pumps. The purpose of this research is to investigate the influence of the blade number on the pump performance and internal flow to enrich the pump design data for low viscous fluid food. The centrifugal pump with an open impeller was used and six impellers having the different blade number were prepared. Performance test using an experimental apparatus was conducted and the numerical analysis was also carried out. In the numerical analysis, the commercial software ANSYS-CFX16.2 was used. The head, shaft power and efficiency obtained by the numerical analysis, are almost the same with the experimental results. The head and shaft power increase with the increase of the blade number. The shear rate, which is concerned to fluid food quality, is high near the inlet region of the blade-to-blade passage for all types of blades. The shear rate of each type of the blade is discussed based on the numerical analysis results and relations between the blade number and shear rate are clarified.