THEORY EXAMINATION (SEM–IV) 2016-17 FLUID MACHINERY

Course: B.Tech (Mechanical Engineering)
Subject Code: ME401
Subject Title: Fluid Machinery
Exam Type: Theory Examination
Duration: 3 Hours
Maximum Marks: 100

SECTION – A (Short Questions – 10 × 2 = 20 Marks)

This section tests quick conceptual understanding of key fluid machinery terms.

Topics Covered:

Torque Converter – device for transmitting and multiplying torque in fluid coupling.

Hydraulic Ram – cyclic water pump powered by water hammer effect.

Hydraulic Accumulator – stores pressurized fluid for intermittent use.

Hydraulic Intensifier – increases pressure of a fluid by energy transfer.

Air Lift Pump – lifts liquids by compressed air injection.

Priming – filling a pump casing with liquid before starting to remove air pockets.

Principle of Turbo-machinery – energy exchange between fluid and rotor through dynamic action.

Jet Pump – uses high-velocity jet to lift or move fluids.

Air Vessel – chamber fitted in reciprocating pumps to reduce pressure fluctuation.

Slip / Negative Slip – difference between theoretical and actual discharge in reciprocating pumps.

These short answers cover all fundamental devices used in hydraulic and fluid machinery systems.

SECTION – B (Descriptive Questions – 5 × 10 = 50 Marks)

Attempt any five. These involve derivations, design calculations, and turbine/pump performance.

Euler’s Equation Derivation → Leads to Bernoulli’s Equation, linking energy per unit weight.

Jet Impact Problem → Jet of diameter 20 mm, velocity 20 m/s, deflecting a hinged plate at 15°. Requires force/weight analysis.

Pelton Wheel Design → Head = 80 m, speed = 300 rpm, output = 103 kW, given Cv=0.98C_v = 0.98Cv​=0.98, speed ratio = 0.45, efficiency = 80%.

Maximum Efficiency Derivation for Pelton Turbine.

Governing Mechanism of Pelton Turbine – detailed diagram and explanation.

Lawn Sprinkler Problem – compute angular speed based on nozzle flow and radius difference.

Characteristic Curves of Reaction Turbines – efficiency, discharge, and head variation.

Centrifugal Pump Problem – outer = 2× inner diameter, 1200 rpm, head = 75 m, flow = 3 m/s; determine vane angles and efficiencies.

This section emphasizes energy equations, turbine design, and centrifugal pump performance.

SECTION – C (Advanced Analytical – 2 × 15 = 30 Marks)

Attempt any two. Questions test deep understanding and diagrammatic representation.

Inward Flow Reaction Turbine Problem –

External diameter = 1 m, breadth = 0.2 m, 15% blockage.

Find discharge, velocity triangles, vane angles, and velocity relations at inlet.

Indicator Diagram Analysis –

Discuss effect of acceleration and friction on pressure variation in reciprocating pumps.

Draw modified indicator diagram explaining losses.

Hydraulic Turbine Design –

Head = 30 m, speed = 300 rpm, discharge = 10 m³/s, efficiency = 90%.

Calculate (i) Specific speed, (ii) Power generated, (iii) Type of turbine suitable.

Key Concepts Covered

Summary

This paper thoroughly evaluates:

The principles and working mechanisms of hydraulic machines.

Derivations and applications of energy equations (Euler, Bernoulli).

Turbine and pump design calculations.

Performance analysis using velocity triangles and efficiency relations.

To score well, students must master:

Conceptual clarity (Section A)

Formula-based problem-solving (Section B)

Graphical and analytical reasoning (Section C)