an introduction to mechanical engineering part 2 pdf
This unit continues from the foundation in thermodynamics laid out in An Introduction to
Mechanical Engineering: Part 1. Its aim is to provide an applied emphasis to the concepts already
learnt. The applications presented here concentrate mainly around power generation from oil,
gas and coal by combustion to provide heat transfer to produce work via steam power. The first
section reviews and refines the information that is relevant from the thermodynamics in Part 1,
and the subsequent sections provide analysis techniques for practical engineering applications.
The material covered will address the properties of working fluids as in Part 1; perfect and
semi-perfect gases and steam are of interest. Here refrigerants are introduced along with
combustion reactions and product gas mixtures, with a focus on application.
Our attention is on what a working fluid can achieve. By manipulating the working fluid, practical
ends can be met:
• air conditioning to affect the temperature and humidity of atmospheric air;
• producing electricity by heating steam with combustion reactions, which drives generators
via steam turbines;
• gas and vapour compressors increase pressure at a given flow rate of fluid;
• combustion gases are used directly to drive engines.
Transferring or insulating heat is involved in all practical thermodynamic processes, and
the modes of transfer and the basic techniques for calculation of heat transfer are presented.
This unit considers how classical thermodynamic machines work and how to calculate the
relationships between heat and work.
The first section considers mixtures of gases, seeing how the volume and mass of each gas
in a mixture relates to the others. Later sections progress on to the chemistry of combustion
reactions and then to the energy release of the reactions whether using gas, liquid or solid
fuels. Moisture is a life-supporting component of our environment and is contained in the
atmosphere – rain, mist and humidity – and in reactants and products of combustion. Mixtures
of gases with moisture have specific properties that require special treatment. The unit shows
how to control atmospheric humidity.