Incorrect Statement for Centrifugal Pumps

The correct answer is option 'A': Discharge α (diameter)

Explanation:

Centrifugal pumps are widely used in various industries for pumping fluids. They work on the principle of converting mechanical energy into fluid kinetic energy and then converting it back to pressure energy.

Understanding the Incorrect Statement:

The incorrect statement states that the discharge of a centrifugal pump is directly proportional to the diameter. However, this statement is incorrect. Let's understand why.

Relationship between Discharge and Diameter:

The discharge of a centrifugal pump is the volume of fluid that is delivered by the pump per unit of time. It is commonly measured in liters per second (L/s) or gallons per minute (GPM).

The diameter of the pump does not have a direct relationship with the discharge. The discharge of a centrifugal pump depends on various factors such as the impeller design, speed, and head. The impeller design affects the flow characteristics and efficiency of the pump.

Relationship between Head and Speed:

The head of a centrifugal pump is the energy imparted to the fluid by the pump. It is the difference in pressure between the inlet and outlet of the pump and is commonly measured in meters or feet.

The head of a centrifugal pump is directly proportional to the square of the speed. This means that if the speed of the pump is doubled, the head will become four times greater.

Relationship between Head and Diameter:

The head of a centrifugal pump is not directly proportional to the diameter. The head primarily depends on the impeller design and the speed of the pump. Increasing the diameter of the pump may affect the flow characteristics, but it does not have a direct impact on the head.

Relationship between Discharge and Speed:

The correct relationship is that the discharge of a centrifugal pump is directly proportional to the speed. If the speed of the pump is increased, the discharge will also increase. This relationship is based on the principle of conservation of mass.

Conclusion:

In summary, the incorrect statement for centrifugal pumps is option 'A': Discharge α (diameter). The discharge of a centrifugal pump is actually directly proportional to the speed, while the head is directly proportional to the square of the speed. The diameter of the pump does not have a direct relationship with the discharge or head.