Thermal Engineering

COURSE OBJECTIVES:

1

To acquire knowledge on the working of steam turbines, IC engines and gas turbines.

2

To introduce the combustion process in IC engines

3

To understand air pollution from IC engines and its remedies.

SYLLABUS:

MODULE

CONTENTS

HOURS

I

Steam engineering- T-s diagram, Mollier chart, Steam cycles- Rankine cycle, Modified Rankine cycle, Relative efficiency, Improvement in steam cycles-Reheat, Regenerative and Binary vapor cycle.

Steam Boilers: Types of boilers –Cochran boiler, Babcock and Wilcox boiler, Benson boiler, LaMont boiler, Loeffler boiler, Velox boiler, Boiler Mountings and Accessories.

Steam nozzles:-Types of nozzle- Velocity of steam, mass flow rate, critical pressure ratio  and its  significance, effect of friction,  super Saturated flow.          

 8

II

Steam turbines: classification, compounding of turbines-pressure velocity variation, velocity diagrams, work done, efficiency, condition for maximum efficiency, multistage turbines-condition line, stage efficiency.

Steam turbine performance-reheat factor, degree of reaction, cycles with reheating and regenerative heating, governing of turbines.

  8

III

Internal combustion engines: classification of I.C. Engines- four stroke

and two stroke I.C. Engines, Comparison of four stroke and two stroke

Engine. Wankel Engine, Air standard cycle-Carnot cycle, Otto cycle; Diesel cycle, dual combustion cycle, comparison of Otto, diesel and dual combustion cycles. Stirling and Ericsson cycles, air standard efficiency, specific work output, work ratio, Actual cycle analysis, deviation of actual engine cycle from ideal cycle.  Rotary engines, Stratified charge engine, super charging of SI and CI Engines – turbo charging. Variable specific heats.      

10

IV

Performance Testing of I.C Engines: Indicator diagram, mean effective

pressure. Torque, Engine power- BHP, IHP. Engine efficiency- mechanical efficiency, volumetric efficiency, thermal efficiency and relative efficiency, Specific fuel consumption. Testing of I.C engines- Morse test, Heat balance test and Retardation test.

Fuels and fuel combustion:  flash point and fire point, calorific value, Fuels for SI and CI engine, Important qualities of SI and CI engine fuels, Rating of SI engine and CI engine fuels, Dopes, Additives, Gaseous fuels, LPG, CNG, Biogas, Producer gas. Analysis of fuel combustion-A/F ratio, equivalence ratio, minimum quantity of air, flue gas analysis, excess air.

 

10

V

Air pollution from I.C. Engine and its remedies: Pollutants from S.I. and C.I. Engines, Methods of emission control, alternative fuels for I.C. Engines; the blending of fuels, Bio fuels.

Combustion in I.C. Engines: Combustion phenomena in S.I. engines; Ignition limits, stages of combustion in S.I. Engines, Ignition lag, velocity of flame propagation, auto ignition, detonation; effects of engine variables on detonation; theories of detonation, octane rating of fuels; pre-ignition; S.I. engine combustion chambers.

Stages of combustion in C.I. Engines; delay period; variables affecting Delay period; knock in C.I. engines, Cetane rating; C.I.  engine Combustion chambers.

10

VI

Gas turbines: classification, Thermodynamic analysis of gas turbine Cycles- open, closed and semi closed cycle; ideal working cycle- Brayton cycle-P-v and T-s diagram, thermal efficiency. Effect of compressor and turbine efficiencies. Optimum pressure ratio for maximum specific work output with and without considering machine efficiencies. Comparison of gas  turbine  and  IC  engines,  Analysis  of  open  cycle  gas  turbine, Improvements of the basic gas turbine cycles-regeneration, intercooling and reheating-cycle efficiency and work output-Condition for minimum compressor work and maximum turbine work. Combustion chambers for gas turbines. Pressure loss in combustion process and stability loop.

10

Semester: 

Spring

Offered: 

2018