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# Advanced Thermodynamics for Engineers: A review

Advanced Thermodynamics for Engineers is targeted at Mechanical Engineers yet it also contains some material that will be familiar to Chemical Engineers.   Anyone who lectures on Thermodynamics will find useful and interesting material inside.  There are substantial and significant additions compared with the 1st edition of 1997, and these additions and the structure of the book are best explained by the chart in the chapter explaining the structure of the book

The Introductory Chapters (1 to 3) are quite brief.  For example, the six Corollaries of the 2nd Law are covered in a single page, so familiarity with the content of the classic texts such as Rogers and Mayhew [1] or Eastop and McConkey [2] are essential.

But from Chapter 4 onwards there is material that is not in these popular texts.   Chapter 4 covers available energy and exergy and this leads to the Rational Efficiency of a Power Plant (Chapter 5)  in an approach that will be familiar to anyone who uses Haywood’s –  Analysis of Engineering Cycles [3].   This is followed by Finite Time Thermodynamics, as pioneered by Bejan; the terminology of which always puzzles me, as it has no apparent connection with time but considers the impact on the efficiency and power output of thermal resistance to heat flow between thermodynamic machines and their heat sources and sinks.

Chapter 7 starts with Maxwell’s Relations and develops the necessary and customary thermodynamic equations, and this leads to Chapter 8 (Equations of State) that rapidly progresses to the van der Waals equation of state.  There is extensive treatment and use of this model of a real fluid leading to two-phase systems, and the illustration of how Maxwell’s equal area rule can be used to identify the saturation line on a p-v state diagram.   One matter that always concerns me is the distinction made between perfect gases and ideal gases, since books use these terms almost interchangeably without specifying exactly what is meant.  Winterbone and Turan avoid the problem by only using the term ideal gas and then, when appropriate, further specifying that the heat capacities are constant (as for a perfect gas).  The difference between a perfect gas and an ideal gas is one that causes confusion, and not just among students.   If a perfect gas is defined as an ideal gas that has constant heat capacities, there is then the issue – how to refer to a gas that is ideal but not perfect?    One answer can be found in Haywood [4], who uses the term semi-perfect.   This might be considered self-contradictory as something is either perfect or imperfect, but in teaching ‘semi-perfect’ has the benefit of being concise, and allows ideal gases to be classified as either perfect or semi-perfect.  Chapter 9 then deals with the properties of non-reacting gaseous mixtures, treating them as semi-perfect gases, in which polynomials are used to define the temperature dependence of the heat capacities and other properties of state.   At this point there might have been examples of water vapour and air mixtures (for applications such as air-conditioning and cooling towers), but maybe this was not considered to be ‘Advanced’ material.

Having established property data for non-reacting mixtures in Chapter 9 the material is used in the next two chapters for chemical reactions in the form of combustion energy calculations; this is after a brief treatment of different fuel components.  Material that might not be familiar to Mechanical Engineers is the use of Enthalpy of Formation and Hess’s Law.  The Enthalpy of Formation is a useful concept because of its generality, and a worked example is used to show the connection with Calorific Value.  Hess’s Law is a merely a reminder that properties of state are independent of the pathway by which a particular state has been achieved.  Chapter 12 then applies the 2nd Law to chemical reactions using Gibbs energy and chemical potential to evaluate the equilibrium constants for chemical reactions; this is in contrast to more introductory texts for mechanical engineers that tend to use the van’t Hoff equilibrium box approach.   Chapter 12 contains many worked examples to show how equilibrium combustion temperatures can be calculated, and what approximations can be made with systems that have multiple equilibrium reactions.   This material is applied in Chapter 13 to show how stoichiometry and pressure affect the composition and temperature when fuel is combusted.   The combustion theme continues in Chapters 14 and 15.  Chemical Kinetics is restricted to the material that is needed to calculate the rate of formation of nitric oxide; the chapter ends with a discussion of other pollutants.  Chapter 15 covers ignition, flames (premixed and diffusion) whether laminar or turbulent and ends with models for engine combustion.   All of this is preliminary material that is used in Chapter 16 to explain combustion in reciprocating IC engines.

The contents flowchart indicates that Chapter 17 on Gas Turbines is dependent on all of the preceding chapters, buts since perfect gas behaviour is assumed and the treatment of combustion is qualitative, then the background material  is all covered within the first 8 chapters.   Much of the material can be found in the standard undergraduate texts, but there is a useful introduction to turbofan engines and their improved propulsive efficiency.   Gas Liquefaction (Chapter 18) follows the approach in Haywood’s –  Analysis of Engineering Cycles, and as the material is not often in thermodynamics textbooks then it is useful to have it here.

Chapter 19 concerns Pinch Technology, which is the optimisation of heat recovery in process plant that has multiple streams of fluids with different heating and cooling requirements; it is also known as process integration.  Many thermodynamics texts do not even mention the concept of a pinch point or present a temperature-enthalpy plot for even a two-stream process.   An exception is Eastop and McConkey [1] who illustrate a simple four-stream process, but it is one in which there is no need for either any additional heat input or cooling below ambient temperatures so that no pinch points are ‘crossed’.   These restrictions do not apply to Chapter 19, which shows how any external heating or cooling requirements can be minimised.  Chapter 20 (Irreversible Thermodynamics) is used to discuss the behaviour of thermocouples and the Peltier effect (but not thermoelectric generation), and coupled diffusion problems in general.

The final chapter is on Fuel Cells and provides both details of the necessary electrochemistry and a summary of the different technology types.   Following the electrochemistry and calculation of the open circuit voltage and flowrates of current and reactants is the treatment of losses in fuel cells, but this does not extend to a discussion of how the efficiency varies as the specific power is increased.

There is no mention of how the off-gas in a solid oxide fuel cell needs to be utilised, for example as fuel for a gas turbine, nor is there a discussion of the balance of plant requirements and how this means that (as with mechanical losses in reciprocating engines) the efficiency falls towards zero as the power output is reduced.   The chapter ends with a discussion of hydrogen manufacture from hydrocarbons and this relates back to the equilibrium calculations of Chapter 12.

Overall I consider this to be a very useful book as in its 550 pages it contains material that is not in other teaching texts.  The treatment is rigorous, and the tables and diagrams are clearly set out.   The book is well written, and has numerous worked examples and student exercises; it certainly deserves to be on the shelf of anyone who teaches thermodynamics to mechanical engineers.

The book is available now on ScienceDirect. Want your own print copy? Enter code STC319 when ordering via the Elsevier store to save up to 30%

• Professor Richard Stone is a Professor in Engineering Science at the Department of Engineering Science at Oxford

References

1              Eastop, T. D., and A. McConkey. Applied thermodynamics for engineering thermodynamics. 5th ed. Prentice Hall, 1993.

2              Rogers, G. F. C., Y. R. Mayhew, Engineering thermodynamics: work and heat transfer, 4th ed. Longman, 1992).

3              Haywood, R. W. Analysis of engineering cycles. 4th ed. Pergamon Press, 1991.

4              Haywood, R. W. Equilibrium Thermodynamics for Engineers and Scientists,  Wiley, 1992

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