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

The B.Tech Applied Thermodynamics (NME401) question paper from the 2016–17 IV Semester Theory Examination is a comprehensive 100-mark, 3-hour exam designed to assess students’ understanding of steam and gas power cycles, boilers, turbines, nozzles, combustion, jet propulsion systems, and Rankine cycle numericals.

The structure and content of this paper are identical to the thermodynamics papers EME401 and ME403, ensuring uniformity across different branches. The exam is divided into three main sections, each testing different levels of thermodynamic proficiency.

SECTION – A (Short Answer Questions, 20 Marks)

This section consists of 10 questions of 2 marks each, testing fundamental thermodynamic definitions and concepts.

Topics include:

Adiabatic flame temperature           Meaning of thrust augmentation in jet engines

Sources of air leakage in condensers

Importance of equivalent evaporation when comparing boilers

Concept of cogeneration (combined heat and power)   
How regeneration improves gas turbine thermal efficiency

Classification of condensers (surface, jet, evaporative)
 Saturation curve and missing quantity

Types of compounding in turbines (velocity, pressure, pressure-velocity)

What a ramjet engine is

These questions ensure clarity in essential terminology used throughout steam and gas power studies.
 

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

This section demands descriptive explanations, cycle sketches, and numerical calculations involving thermodynamic processes.

1. Gas Turbine Cycles with Modifications

Explain gas turbine cycle with:

Intercooling

Reheat + Regeneration

Reheat + Intercooling

2. Choked Flow & Nozzle Friction

Definition of choked flow, sonic velocity conditions, and the effect of friction on nozzle efficiency and mass flow.

3. Steam Engine Indicator Diagrams

(i) Hypothetical vs actual indicator diagrams, diagram shape explanation
(ii) Meaning of diagram factor, plus explanation of saturation curve & missing quantity

4. Rankine Cycle with Reheat – Numerical

Steam entering HP turbine: 20 MPa, 500°C
Exiting LP turbine: 90% dryness
Condenser pressure: 0.005 MPa
Reheated to 500°C

Students determine:

HP turbine exit pressure

Thermal efficiency of the cycle

5. Babcock & Wilcox Boiler

Neat sketch, working, features, water circulation, and advantages.

6. Natural Draught Chimney Numerical

Given:

Height = 60 m                                             Flue gas temp = 300°C

Ambient air = 17°C                                      Air requirement = 19 kg/kg fuel

cp = 1.0032 kJ/kg·K                                     Fuel calorific value = 32604 kJ/kg

Artificial draught exit: 150°C

Calculate:
(i) Draught (mm of water)
(ii) Chimney efficiency
(iii) Heat lost via flue gases per kg fuel

7. Combustion Analysis (C₈H₁₈ + Air)

Determine % CO₂ by volume in dry exhaust gas (CO₂, CO, N₂ considered).

8. Steam Nozzle Expansion

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

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

This section includes advanced cycle analysis and turbine velocity diagram calculations.

Q3 – Ideal Rankine Cycle (100 MW Output)

Steam:

Turbine inlet: 8 MPa, saturated vapour    Condenser exit: 0.008 MPa, saturated liquid

Students must calculate:                             Thermal efficiency

Back work ratio                                            Steam mass flow rate (kg/h)

Q4 – Jet Propulsion + Impulse Turbine Numerical

(a) Principles of:

Jet propulsion                                       Turbojet engine

Turboprop engine                                 Rocket propulsion

(b) Turbine data:

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 angle = inlet angle – 3°               Students compute:

Blade inlet & outlet angles                     Power developed

Q5 – Single Stage Impulse Turbine (Velocity Diagram Problem)

Given:

Isentropic enthalpy drop = 200 kJ/kg

Nozzle efficiency = 96%

Nozzle angle = 15°

Blade velocity coefficient = 0.96

Blade speed ratio = 0.5

Steam mass flow = 20 kg/s

Steam inlet velocity = 50 m/s

Determine:
(i) Blade angles (smooth entry & axial exit)
(ii) Blade efficiency
(iii) Power in kW
(iv) Axial thrust