Thermal Systems

Code:

EM0100

Acronym:

ST

Keywords
Classification	Keyword
OFICIAL	Heat Transfer and Fluid

Instance: 2013/2014 - 2S

Active?	Yes
Responsible unit:	Fluids and Energy Division
Course/CS Responsible:	Master in Mechanical Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
MIEM	189	Syllabus since 2006/2007	4	-	6	45,5	162

Teaching language

Portuguese

Objectives

Objectives: This course aims to acquaint students with the knowledge, the understanding and application of the fundamental principles of the different thermal machines. Learning Outcomes: Students should know how to identify the main characteristics of behaviour and select the most suitable one between different options and systems.

Learning outcomes and competences

Knowledge of the thermodynamics of machines and thermal equipments.

Working method

Presencial

Pre-requirements (prior knowledge) and co-requirements (common knowledge)

Thermodynamics, Fluid Mechanics and Heat Transfer

Program

COMBUSTION AND FUELS

Slow and fast combustion. Premixed and diffusin flames. Deflagration and detonation.

Gaseous fuels. Liquid fuels. Solid fuels.

Mass conservation and chemical equation.

The mixture of liquid and gaseous fuels.

Combustion products. Wet and dried products.

Complete oxidizing combustion.

Reducing combustion. Incomplete combustion. Lean and rich mixtures.

Simplified combustion calculations. The first law of thermodynamics applied to combustion. Internal energy and enthalpy of combustion. Enthalpy and internal energy of formation. Heating values.

Adiabatic flame temperature.

The second law of thermodynamic applied to combustion. The third law and the absolute entropy.

Maximum work of a chemical reaction.

Dissociation. Equilibrium or dissociation constant. Reversible combustion. The dissociation constant and the Gibbs function.

Interchangeability of fuel gases. The Wobbe index.

Fuels for internal combustion engines. Gasolines. The octane number. Anti-knock additives. The destilation curve. Benzene. The LPG’s. Alcohols. Diesel fuels. The cetane number. The biodiesel. Wood and wood derived fuels and biomass fuels. Other petroleum derived fuels. The acid dew point of combustion products.

 

BOILERS

Definition, characteristics and types. Main components of boilers. The fuel tube versus water tube boilers.

Determination of boiler efficiency. The simplified ASME indirect method for the calculation of boiler efficiency.

 

INTERNAL COMBUSTION ENGINES

The reference air cycles for internal production engines. Mean effective pressure of a cycle. The Otto air cycle and its particularities. The Diesel air cycle and its particularities. The dual or Sabathiée air cycle. The comparison of the three air cycles. The indicated cycle. The Otto and Diesel indicated cycles. Admission in the four stroke cycles. The residual gases. Volumetric efficiency. Indicated two stroke cycles. Otto engine blow down process. Diesel engine blow down process. Two stroke engines blow down types.

Parameters for the qualification and qualification of engine performance. Effective power, mean effective pressure, mechanical efficiency. Specific fuel consumption. Engine elasticity and drivability

 

COMPRESSED AIR PLANTS

The compressed air network. Design and layout of a compressed air system. Evaluation of compressed air needs. Fluid friction pressure losses. Minor pressure losses.

The sizing of compressed air tanks. Simplified calculation procedures.

Air compressors. Alternative compressors. The volumetric efficiency. The indicated compression cycle. Compression in stages.

Screw, tooth, roots, vane and scroll compressors. Dynamic compressors. Axial and centrifugal compressors.

 

ORGANIC RANKINE CYCLE

Comparison between an organic Rankine cycle and a steam cycle. Important applications: Biomass combustion; geothermal energy recovery; solar energy; waste thermal energy recovery.

Working fluids. Saturation curves. Thermo physical properties of working fluids. Environmental impact, price and health effects.

Equipments. Expanders: Screw, scroll and rotating vane expanders.

Thermodynamic properties for ORC working fluids.

 

STEAM PLANTS

Components of a steam plant. The boiler or steam generator. The steam piping. Steam traps. Pressure reducing devices. The condensate piping. Design recommendations. Heat losses in valves and fittings. Thermal isolation of stream lines. The flash steam.

 

THERMAL FLUID PLANTS

Heat transfer thermal fluid plants. Liquid phase systems. Comparison among heat transfer fluids. Organic thermal fluids. Main properties. Main components of a thermal fluid plant. Boiler, circulating pump, expansion vessel, degasifier, overl collecting tank.

Typical thermal fluid plants.

Design recommendations. Plant filling and start up.

Important physical for the thermal design. Properties of thermal fluids. The thermal insulation of thermal fluid plants.

 

 Scientifical Component: 70%
Technological Component: 30 %

Mandatory literature

Mendes Juanico; Geradores de Vapor, 1995
Jorge Martins; Motores de Combustão Interna, Publindústria, 2005
Eastop e Mconkey; Applied Thermodynamics for Engineering Technologists, Prentice Hall, 1993

Teaching methods and learning activities

Theoretical classes: course themes presentation with transparencies Problem solving

keywords

Technological sciences > Engineering > Thermal engineering

Evaluation Type

Distributed evaluation with final exam

Assessment Components

Designation	Weight (%)
Exame	95,00
Participação presencial	5,00
Total:	100,00

Amount of time allocated to each course unit

Designation	Time (hours)
Estudo autónomo	80,00
Frequência das aulas	82,00
Total:	162,00

Eligibility for exams

According to General Evaluation Rules of FEUP

Calculation formula of final grade

Final Exam with a grade from 0 to 20. Theoretical part (30% of the Final Exam Mark), practical part (70% of the Final Exam Mark) Practical part of the exam (open book exam). Theoretical part of the exam (closed book exam).

Special assessment (TE, DA, ...)

Final exam with a theoretical and a practical part

Classification improvement

Final exam with a theoretical and a practical part.

Observations

Practical part of the exam (open book exam). Theoretical part of the exam (closed book exam).