Introduction to Engineering Thermodynamics (FST 204)

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27 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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Lecture Note

Definition


Thermodynamics is derived from two words: ‘Thermo’
which means ‘Heat energy’ and ‘Dynamics’ which
means ‘conversion’ or ‘transformation’



Concisely, thermodynamics is a division of science that
deals with conversion of energy from one form to
another



The main forms of energy of interest in engineering
thermodynamics are heat and work




Definition contd.


Work is the form of energy useful in displacement of a
body




Heat is the form of energy transferred due to
temperature gradient between two bodies



Applications of Engineering Thermodynamics


Engineering application of thermodynamic principles
is the design of various systems using fluid properties
to cause energy transformation



Applications in design of heat engines, refrigeration
machines, air conditioning systems


Scope of Thermodynamics


It is limited to macroscopic properties of matter i.e.
properties of large number of particles of systems



It considers the initial and final states of a system and
not the mechanism of the process



Important fluid properties in thermodynamics


Density


Specific heat capacity


Temperature


Internal energy


Entropy


Enthalpy


Pressure


Specific volume


Mass


Fundamental concepts


System


Boundary


Surrounding


Open, Closed and Isolated



Homogenous and heterogeneous


Energy


Kinetic energy


Potential energy


Internal energy

Heat Engines


Heat engines are devices designed for the purpose of
converting other forms of energy (usually in the form
of heat) to work.


Heat engines differ considerably
from one another, but all can be characterized by the
following:


1. They receive heat from a high
-
temperature source
(solar energy, oil furnace, nuclear reactor, etc.).


2. They convert part of this heat to work (usually in the
form of a rotating shaft).


3. They reject the remaining waste heat to a low
-
temperature sink (the atmosphere, rivers, etc.).


4. They operate on a cycle.