BME Hydraulic Machines 4

Question 1

The slip in a reciprocating pump is defined as:

Accepted Answer

Difference between theoretical and actual discharge expressed as a fraction of theoretical discharge

Answer

Slip = (Q_theoretical − Q_actual) / Q_theoretical, representing losses due to leakage and valve timing; negative slip is possible if inertia effects increase actual discharge.

Question 2

A Kaplan turbine differs from a propeller turbine in that:

Accepted Answer

Its runner blades are adjustable, allowing efficient part-load operation

Answer

Kaplan turbines have adjustable (controllable-pitch) runner blades that, combined with adjustable guide vanes, maintain high efficiency over a wide range of flows and heads.

Question 3

Manometric efficiency of a centrifugal pump is the ratio of:

Accepted Answer

Actual head developed to Euler's (theoretical) head

Answer

Manometric efficiency = H_m / H_Euler, reflecting hydraulic losses (friction, turbulence) between the ideal energy added by the impeller and the actual manometric head.

Question 4

The purpose of a surge tank in a hydropower system is to:

Accepted Answer

Protect the penstock from water hammer during load changes

Answer

A surge tank provides a water surface close to the turbine that absorbs pressure transients when turbine load changes, protecting the penstock from water hammer.

Question 5

In the Euler turbomachinery equation, the torque on the runner depends on:

Accepted Answer

Change in the whirl (tangential) component of absolute velocity

Answer

Euler's equation states T = ρQ(r₁V_w1 − r₂V_w2); only the whirl (tangential) velocity components contribute to angular momentum change and thus torque.

BME - Bachelor of Mechanical Engineering Practice Test

BME - Bachelor of Mechanical Engineering Practice Test

BME Hydraulic Machines 4