Post Test

What is the formula to calculate the velocity of fluid in a centrifugal pump?

• V = Q / A

• V = Q * A

• V = 2πr / t

• V = A / Q

If the diameter of the impeller is 0.5 m and the rotational speed is 1500 RPM, what is the velocity of the fluid?

• 60.0 m/s

• 25.5 m/s

• 15.75 m/s

• 39.25 m/s

Answer explanation

The velocity of the fluid can be calculated using the formula: V = π * D * N / 60, where D is the diameter in meters and N is the RPM. Substituting D = 0.5 m and N = 1500 gives V = 39.25 m/s, which is the correct answer.

How does the velocity of the fluid affect the pump's performance?

• The velocity of the fluid directly impacts flow rate and pressure, affecting pump efficiency and performance.

• Fluid velocity only affects the temperature of the pump.

• Higher fluid velocity always leads to lower efficiency.

• The velocity of the fluid has no effect on pump performance.

What factors influence the friction loss in a centrifugal pump?

• Ambient temperature

• Pump material type

• Fluid viscosity, flow rate, pipe diameter, pipe length, surface roughness, and fittings.

• Pump speed

What is the Darcy-Weisbach equation used for in pump calculations?

• To calculate pressure loss in fluid flow through pipes.

• To calculate the flow rate of a fluid in a tank.

• To determine the efficiency of a pump.

• To measure the temperature of fluid in pipes.

If the friction factor is 0.02, what is the head loss due to friction in a 50 m long pipe?

• The head loss is 10 m.

• Head loss cannot be calculated without the diameter and velocity of the fluid.

• The head loss is 0.5 m.

• The head loss is 1.5 m.

How do you determine the Reynolds number for flow in a centrifugal pump?

• Re = (ρ * D) / (v * μ)

• Re = (ρ * v * D) / μ

• Re = (ρ * v) / D

• Re = (v * D) / (ρ * μ)

What is the significance of the pump's efficiency in relation to velocity and friction?

• The pump's efficiency has no impact on fluid dynamics.

• Higher efficiency always leads to increased friction losses.

• Velocity is independent of the pump's efficiency.

• The pump's efficiency directly affects fluid velocity and friction losses.

Explain how to minimize friction losses in a piping system connected to a centrifugal pump.

• Increase the number of bends and fittings

• Select rough materials

• Use smaller diameter pipes

• Use larger diameter pipes, minimize bends and fittings, select smooth materials, ensure proper alignment, maintain consistent flow, and regularly inspect the system.

What role does the pump's rotational speed play in determining fluid velocity?

• Fluid velocity is only affected by the pump's design.

• Lower rotational speed always leads to higher fluid velocity.

• Rotational speed has no effect on fluid velocity.

• Higher rotational speed increases fluid velocity.