Page 6 - BASIC CONCEPTUAL OF THERMOFLUID

CHAPTER 1: CONCEPTUAL PRINCIPLE IN THERMOFLUIDS

Thermodynamics: the study of energy, energy transformations and its relation to matter. The analysis of
thermal systems is achieved through the application of the governing conservation equations, namely
Conservation of Mass, Conservation of Energy (1st law of thermodynamics), the 2nd law of
thermodynamics and the property relations.

Heat Transfer: the study of energy in transit including the relationship between energy, matter, space
and time. The three principal modes of heat transfer examined are conduction, convection and radiation,
where all three modes are affected by the thermophysical properties, geometrical constraints and the
temperatures associated with the heat sources and sinks used to drive heat transfer.

Fluid Mechanics: the study of fluids at rest or in motion. While this course will not deal extensively with
fluid mechanics, we will be influenced by the governing equations for fluid flow, namely Conservation of
Momentum and Conservation of Mass.

1.2 Solid, Liquids and Gases
Understanding the difference between Solid Liquid and Gas is important as they represent the
three different states of matter. As we know, everything around us is matter and it is important to
understand the classification of matter; primarily into Solids, Liquids and Gases. A solid can be classified
as a substance that is rigid with low intermolecular spacing and high intermolecular forces, that binds all
molecules within together. Liquids, on the other hand, are less rigid and flow easily. They usually have
properties that enable them to flow from higher areas to lower areas. This is a unique property of liquids
when compared to solids. However, there are a few imperfections in solids. The main describe in Table 1
below:

Table 1: Properties of solid, gases and liquid

SOLID LIQUIDS GASES

Have definite shape and Have definite volume and Have definite volume
volume no definite shape and no definite shape
Intermolecular between The intermolecular space is The intermolecular
space is absent moderate but present. space is free-flowing
and plenty.
Incompressible Incompressible Gases can be
compressed quite
easily.
The force attraction The force of attraction There is no
between molecule is high between molecules is pretty intermolecular force of
moderate. attraction between the
molecules.

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