Pump Characteristics

Outline of pump characteristics In the industry, the performance specification of a particular pump may be known, but the test is usually based on water as a pump medium. In the case of liquids with a significantly higher viscosity than water, these performance curves may be accurate only at certain flow rates or may be totally ineffective, requiring readjustment of the specification of higher viscosity liquids You might. The purpose of this experiment was to investigate the performance and properties of the centrifugal pump used to pump the glycol solution, its motor and the corresponding piping system.

Pump characteristics are usually graphically described by the manufacturer as pump performance curves. The pump performance curve shows the relationship between actual pump flow rate and head. It also contains other important information for proper pump selection, such as efficiency curve, NPSHr curve, multiple impeller diameters, pump curves per speed, power consumption and so on.

The number of impeller vanes is an important design of the pump, which greatly influences the characteristics of the pump. At the moment the investigation focuses mainly on the performance characteristics of the axial flow pump and the influence of blade number on the internal flow field. As the number of blades increases, the indenter of the model pump also increases, the variable adjustment of efficiency and cavitation characteristics becomes complicated, but the number of each blade has the optimum value. The research contributes to the hydraulic design of the centrifugal pump. For example, the impeller blades are shown in FIG. On the other hand, if the number of impeller blades is too large, the extrusion effect at the impeller becomes very serious. The area of ​​the impeller becomes larger, and it becomes difficult for the fluid to flow through the gap, but the flow velocity increases

Pump performance and cavitation characteristics are affected by the number of blades, one of the most important design considerations of the pump. If the number of blades is too large, the influence of the impeller becomes very large, the flow velocity increases, the interface between fluid interfaces increases, and if the number of blades is too small, the diffuser loss increases as the number of blades increases. Diffusion range of the flow path According to research by the Fluid Mechanical Engineering Research Center, the number of the blades increases, the restriction between the blades and the flow becomes more obvious, the phenomenon of "spray and wake flow" inside the impeller becomes inconspicuous, This is very noticeable in the flow path. Against the tongue of Volute. As the number of blades increases, it is concluded that mixing losses of "jet" and "late flow" in the centrifugal pump will decrease, thereby increasing output.