Pipefitter Pipe Systems and Fluid Mechanics 4

Question 1

In a piping system, cavitation is most likely to occur at which location?

Accepted Answer

At the pump suction where pressure drops below vapor pressure

Answer

Cavitation occurs at the pump suction side when local pressure falls below the fluid's vapor pressure, causing vapor bubbles to form and collapse.

Question 2

What does the term 'hydraulic gradient' describe in a piping system?

Accepted Answer

The rate of pressure drop per unit length of pipe

Answer

The hydraulic gradient represents the rate of pressure head loss per unit length along a pipe, indicating how pressure decreases due to friction.

Question 3

When two pipes of different diameters are joined in series, which parameter remains constant throughout?

Accepted Answer

Volumetric flow rate

Answer

By the continuity equation, volumetric flow rate (Q = A × V) remains constant in series piping, though velocity changes with cross-sectional area.

Question 4

A pipe system experiences water hammer. Which device is BEST suited to protect against this condition?

Accepted Answer

A surge suppressor or accumulator

Answer

Surge suppressors and accumulators absorb the sudden pressure spike of water hammer by providing a compressible cushion in the system.

Question 5

In fluid mechanics, what is the significance of a Reynolds number greater than 4000?

Accepted Answer

Flow is fully turbulent

Answer

A Reynolds number above 4000 indicates fully turbulent flow, where fluid moves in irregular, chaotic eddies rather than smooth layers.

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