RESEARCH INTO THE ORIGINS OF ENGINEERING THERMODYNAMICS (original) (raw)
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A Novel Sequence of Exposition of Engineering Thermodynamics *
Journal of Energy Resources Technology, 2014
We present the foundations of thermodynamics in a novel sequence in which all basic concepts are defined in terms of well known mechanical ideas. Many definitions are new. The order of introduction of concepts is: system (constituents and parameters); properties; state; energy (without heat and work) and energy balance; classification of states in terms of time evolution; existence of stable equilibrium states; available energy; entropy (without heat and temperature) of any state (equilibrium or not) and entropy balance; properties of stable equilibrium states; temperature in terms of energy and entropy; chemical potentials; pressure; work; heat; applications of balances. This novel sequence not only generalizes the subject of thermodynamics to all systems (large or small) and all states (equilibrium and not equilibrium) but also avoids both the conceptual and definitional difficulties that have been recognized by so many teachers, and the confusion experienced by so many students.
Reconsidering the Foundations of Thermodynamics from an Engineering Perspective
Currently, there are two approaches to the foundations of thermodynamics. One, associated with the mechanistic Clausius-Boltzmann tradition, is favored by the physics community. The other, associated with the post-mechanical Carnot tradition, is favored by the engineering community. The bold hypothesis is that the conceptual foundation of engineering thermodynamics is the more comprehensive. Therefore, contrary to the dominant consensus, engineering thermodynamics (ET) represents the true foundation of thermodynamics. The foundational issue is crucial to a number of unresolved current and historical issues in thermodynamic theory and practice. ET formally explains the limited successes of the 'rational mechanical' approaches as idealizing special cases. Thermodynamic phenomena are uniquely dissymmetric and can never be completely understood in terms of symmetry-based mechanical concepts. Consequently, ET understands thermodynamic phenomena in new way, in terms of the post-mechanical formulation of action. The ET concept of action and the action framework trace back to Maupertuis's Principle of Least Action, both clarified in the engineering worldview research program of Lazare and Sadi Carnot. Despite the intervening Lagrangian 'mechanical idealization of action', the original dualistic, indeterminate engineering understanding of action, somewhat unexpectedly, re-emerged in Planck's quantum of action. The link between engineering thermodynamics and quantum theory is not spurious and each of our current formulations helps us develop our understanding of the other. Both the ET and quantum theory understandings of thermodynamic phenomena, as essentially dissymmetric (viz. embracing complementary), entail that there must be an irreducible, cumulative historical, qualitatively emergent, aspect of reality.
2013
As well as many other people, we have felt, both as students and as teachers, that some traditional approaches present ambiguities and logical inconsistencies in the exposition of the basics of thermodynamics. Since the late ’80s we have adopted an approach developed over thirty years of course and research work at M.I.T.: rooted in the work of Hatsopoulos and Keenan [1], it has been presented in a systematic and detailed way by Gyftopoulos and Beretta [2]. On the basis of our teaching experience we believe that this approach is particularly suited for students attending engineering programs and our goal here is to underline the most important reasons of its success. In the paper we summarize and discuss how we have adapted the sequence of arguments proposed in [2, Chaps. 2-14] to meet the needs of undergraduate engineering students.
Study Guide for Thermodynamics: an Engineering Approach
A area (m 2 ) C P specific heat at constant pressure (kJ/(kg⋅K)) C V specific heat at constant volume (kJ/(kg⋅K)) COP coefficient of performance d exact differential E stored energy (kJ) e stored energy per unit mass (kJ/kg) F force (N) g acceleration of gravity ( 9.807 m/s 2 ) H enthalpy (H= U + PV) (kJ) h specific enthalpy (h= u + Pv) (kJ/kg) h convective heat transfer coefficient (W/(m 2 ⋅K) K Kelvin degrees k specific heat ratio, C P /C V k 10 3 k t thermal conductivity (W/(m-°C)) M molecular weight or molar mass (kg/kmol) M 10 6 m mass (kg) N moles (kmol) n polytropic exponent (isentropic process, ideal gas n = k) η isentropic efficiency for turbines, compressors, nozzles η th thermal efficiency (net work done/heat added) P pressure (kPa, MPa, psia, psig) Pa
A New Approach to Understanding Engineering Thermodynamics from Its Molecular Basis
AWARDED ASME HONOURS: Engineering Thermodynamics is that engineering science in which students learn to analyze dynamic systems involving energy transformations, particularly where some of the energy is in the form of heat. It is well known that people have difficulty in understanding many of the concepts of thermodynamics; in particular, entropy and its consequences. However, even more widely known concepts such as energy and temperature are not simply defined or explained. Why is this lack of understanding and clarity of definition prevalent in this subject? Older engineering thermodynamics textbooks (often containing the words "heat engines" in the title) had a strong emphasis in their early chapters on the general physical details of thermodynamic equipment such as internal and external combustion engines, gas compressors and refrigeration systems. The working fluid in these systems might expand or contract while heat, work and mass might cross the system boundary. The...
Applied Thermodynamics course outline
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Introduc on and the first law of thermodynamics 1.1 heat, work, and the system 1.2 units. 1.3 the state of the working fluid. 1.4 reversibility 1.5 reversible work 1.6 conversa on of energy and the first law of thermodynamics. 1.7 the non-flow equa on 1.8 the steady-flow equa on. 2. The working fluid 2.1 liquid, vapour, and gas. 2.2 the use of vapour tables 2.3 the perfect gas 3. Reversible and irreversible processes 3.1 reversible non-flow processes 3.2 reversible adiaba c non-flow processes 3.3 polytrophic processes 3.4 reversible flow processes 3.5 irreversible processes 3.6 nonsteady-flow processes 4. The second law 4.1 the heat engine 4.2 entropy 4.3 the T-s diagram 4.4 reversible processes on the T-s diagram 4.5 entropy and irreversibility 4.6 exergy 5. The heat engine cycle 5.1 the carnot cycle 5.2 absolute temperature scale 5.3 the carnot cycle for a perfect gas 5.4 the constant pressure cycle 5.5 the air standard cycle 5.6 the o o cycle 5.7 the diesel cycle 5.8 the dual-combus on cycle 5.9 mean effec ve pressure 5.10 the s rling and ericsson cycles 6. Mixtures