THEORY EXAMINATION (SEM–IV) 2016-17 APPLIED THERMODYNAMICS

The B.Tech Applied Thermodynamics (EME401) question paper from the 2016–17 IV Semester Theory Examination is a 100-mark, 3-hour comprehensive assessment covering gas turbines, steam boilers, Rankine cycle, jet propulsion, combustion, condensers, turbines, nozzles, chimneys, and thermodynamic performance calculations. The paper is divided into three extensive sections testing conceptual clarity, cycle analysis, numerical proficiency, and engineering application skills.

SECTION – A (Short Answer Questions, 20 Marks)

This section consists of 10 questions of 2 marks each, covering fundamental thermodynamic concepts and components used in power generation and propulsion.

The topics include:

Adiabatic flame temperature definition

Meaning of thrust augmentation in jet engines

Sources of air leakage in condensers

Use of equivalent evaporation for boiler comparison

Concept of cogeneration for combined heat & power

Effect of regeneration in gas turbines on thermal efficiency

Classification of condensers (jet, surface, evaporative, etc.)

Saturation curve and missing quantity in boilers/steam tables

Compounding in turbines (pressure, velocity, pressure-velocity compounding)

Definition of Ramjet propulsion

These basic questions ensure understanding of key terminologies and principles.

SECTION – B (Descriptive & Numerical Questions, Any 5 × 10 = 50 Marks)

This section includes medium-length problems requiring detailed explanation, thermodynamic analysis, diagrams, and numerical calculations.

1. Gas Turbine Cycles

Explaining gas turbine cycle modifications:

With intercooling

With reheat & regeneration

With reheat & intercooling

2. Choked Flow & Nozzle Friction

Definition of choked flow, its thermodynamic significance, and friction effects in nozzles.

3. Steam Engine Indicator Diagram

(i) Hypothetical vs actual indicator diagram
(ii) Diagram factor explanation
plus explanation of saturation curve & missing quantity.

4. Rankine Cycle Problem with Reheat

Steam enters HP turbine at 20 MPa, 500°C, leaves LP turbine at 90% dryness, condenser pressure 0.005 MPa, reheated to 500°C.
Students must determine:

Pressure at exit of HP turbine

Thermal efficiency

5. Babcock & Wilcox Boiler

Construction, working, features, and water circulation explained with a neat sketch.

6. Natural Draught Chimney Problem

Given: 60 m high chimney, flue gas temperature 300°C, atmospheric 17°C
Students calculate:
(i) Draught in mm of water
(ii) Chimney efficiency
(iii) Heat carried away by flue gases per kg of fuel

7. Combustion Problem (C₈H₁₈ with Air)

Calculate percentage by volume of CO₂ in dry exhaust gas using fuel–air ratio and combustion products.

8. Steam Nozzle Flow

Steam expansion from 16 bar → 5 bar, initial T = 300°C, mass flow 1 kg/s
Calculate throat & exit areas for:
(i) Frictionless flow
(ii) 10% friction loss

SECTION – C (Long Analytical Questions, Any 2 × 15 = 30 Marks)

These questions require deep thermodynamic reasoning, cycle evaluation, and turbine/jet propulsion engineering.

Q3 – Ideal Rankine Cycle Analysis (100 MW plant)

Steam:

Saturated vapour at 8 MPa enters turbine    Saturated liquid at 0.008 MPa exits condenser

Students must determine:                               Thermal efficiency

Back work ratio                                                Mass flow rate (kg/h) of steam

Q4 – Jet Propulsion + Impulse Turbine Problem

(a) Principles of:

Jet propulsion                                                Turbojet engine

Turboprop engine                                          Rocket propulsion

(b) Impulse turbine problem:
Given:

Mass flow = 5 kg/s                                           Rotor diameter = 1.2 m

Speed = 3000 rpm                                           Nozzle angle = 18°

Blade speed ratio = 0.4                                    Velocity coefficient = 0.9

Outlet blade angle = 3° less than inlet            Students determine:

Blade angles                                                     Power developed

Q5 – Single Stage Impulse Turbine with Given Parameters

Given:

Isentropic enthalpy drop = 200 kJ/kg             Nozzle efficiency = 96%

Nozzle angle = 15°                                          Blade velocity coefficient = 0.96

Blade speed ratio = 0.5                                   Mass flow = 20 kg/s

Steam inlet velocity = 50 m/s

Find:
(i) Blade inlet & outlet angles
(ii) Blade efficiency
(iii) Power developed (kW)
(iv) Axial thrust

This requires a detailed velocity diagram solution.