ABC Pumping Systems and Hydraulics 2

Question 1

According to the affinity laws, if pump speed is doubled, the power (brake horsepower) required changes by a factor of:

Accepted Answer

8

Answer

By the third affinity law, power varies as the cube of speed, so doubling the speed increases power requirements by 2³ = 8 times.

Question 2

What does the specific speed of a pump indicate?

Accepted Answer

The type of impeller design best suited for given flow and head conditions

Answer

Specific speed is a dimensionless index that classifies pump impeller geometry and is used to select the best impeller design for specific flow and head requirements.

Question 3

In a parallel pump configuration, what happens to total flow and head compared to a single pump?

Accepted Answer

Flow increases, head remains approximately the same

Answer

Pumps in parallel add their flows at the same head, increasing total flow capacity while the total head remains approximately constant.

Question 4

What instrument is used to measure the flow rate in a pressurized water main using pressure differential?

Accepted Answer

Venturi meter or Pitot tube

Answer

A Venturi meter or Pitot tube measures flow by detecting pressure differential created by flow velocity in a pressurized pipe.

Question 5

The volute casing of a centrifugal pump is designed to:

Accepted Answer

Convert velocity head to pressure head as water exits the impeller

Answer

The volute's gradually expanding cross-section converts kinetic energy (velocity head) from the impeller into potential energy (pressure head).

(ABC) Association of Boards of Certification Practice Test

(ABC) Association of Boards of Certification Practice Test

ABC Pumping Systems and Hydraulics 2