As the impeller wears, how does pump efficiency change?

As the impeller wears, how does pump efficiency change?

• A. Decrease
• B. Improve
• C. Increase
• D. No Change

Answer: (A)

Wear on the impeller reduces a pump’s efficiency because it degrades how effectively the pump converts electrical power into hydraulic energy. Efficiency is the hydraulic power delivered to the fluid divided by the electrical power put in. When the impeller wears, the clearance between the impeller and the casing increases, causing slip and internal leakage so less energy is transferred to the fluid. The worn surfaces also disrupt the flow path, creating more turbulence and friction losses inside the pump. All these factors waste more power as heat and friction, so the pump delivers less hydraulic power for the same input power. So, as the impeller wears, efficiency declines.

Wear on the impeller reduces a pump’s efficiency because it degrades how effectively the pump converts electrical power into hydraulic energy. Efficiency is the hydraulic power delivered to the fluid divided by the electrical power put in. When the impeller wears, the clearance between the impeller and the casing increases, causing slip and internal leakage so less energy is transferred to the fluid. The worn surfaces also disrupt the flow path, creating more turbulence and friction losses inside the pump. All these factors waste more power as heat and friction, so the pump delivers less hydraulic power for the same input power. So, as the impeller wears, efficiency declines.