The occurrence of circumferential flow at the outlet of centrifugal pumps
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This post was last edited by Cuaili Yisu on 2018-4-23 at 15:03. When designing centrifugal pumps, we usually arrange the inlet and outlet so that they are not located right next to elbows, as this can lead to circulatory flow. What exactly is circulatory flow? What effects does the vortex flow phenomenon have on pumps?
If a centrifugal pump operates at low flow rates, circular flow vortices are formed within the pump, generating radial forces that cause the impeller to become unbalanced. This increases the load on the bearings, leading to damage to the seals and bearings. Severe low flow rates can also raise the fluid temperature, damage the impeller and pump casing, increase the deflection of the pump shaft, and even cause the shaft to suffer from fatigue fractures. Selecting the correct flow rate and head ensures that the centrifugal pump operates at its optimal performance level.
Theoretical head of a centrifugal pump: Assumptions: a) The number of blades inside the impeller is infinite, the thickness of the blades is infinitesimally small, and there is no circulation at all； b. The liquid is an ideal fluid with zero viscosity; there is no resistance to its flow. These are the assumptions for calculating the theoretical head of a centrifugal pump. In fact, it is impossible for the number of blades on an impeller to be infinite, nor can the thickness of the blades be infinitely thin. As long as there is a pressure difference, the liquid will flow