Why Is There Power Loss in Centrifugal Pumps

Oct 17, 2024

Centrifugal pumps, as widely used fluid conveying equipment in the industrial field, have a direct impact on the energy consumption and cost of the entire production system due to their operational efficiency. During the operation of centrifugal pumps, power loss is an issue that cannot be ignored.
This article will explore in detail the types and causes of power loss in centrifugal pumps, as well as their impact on pump performance, and propose corresponding optimization measures.
The power loss in centrifugal pumps is mainly divided into three types: volume loss, hydraulic loss, and mechanical loss.
1. Volume loss
The volume loss is mainly caused by the gap between the impeller and the pump body of the centrifugal pump, as well as leakage at the shaft seal. When the impeller rotates, a portion of the fluid flows back from the gap between the impeller and the pump body to the inlet of the impeller, or leaks out from the shaft seal, and these fluids that are not effectively transported are known as volume loss.
For multi-stage pumps, similar leakage can also occur from the balance plate. Volume loss not only reduces the output flow rate of the pump, but also increases the energy consumption of the pump.
2. Hydraulic losses
Hydraulic loss is the energy loss caused by friction, collision, vortex and other phenomena during the flow of fluid in the pump body. When the fluid flows through the flow channel of the pump body, if the surface of the flow channel is rough or the design is unreasonable, it will cause an increase in fluid resistance, resulting in hydraulic loss.
In addition, when the fluid enters the impeller and rotates with it, collisions and eddies are generated due to changes in velocity direction and magnitude, further exacerbating hydraulic losses. Hydraulic losses directly affect the head and efficiency of the pump.
3. Mechanical losses
Mechanical losses are mainly caused by friction and incomplete energy conversion between various components inside the pump.
For example, friction occurs between the shaft and components such as bearings and packing during rotation, which consumes some power; The friction between the front and rear cover plates of the impeller and the fluid can also cause energy loss. In addition, when the impeller rotates at high speed inside the pump, due to incomplete conversion of fluid kinetic energy, a portion of the energy is also lost to the environment in the form of thermal energy. Although mechanical losses are relatively small, they cannot be ignored.