Should Engineering Thermodynamics Include a Simplified Treatment of Its Underlying Molecular Basis?

Volume 6: Engineering Education and Professional Development

2010

Traditionally, Engineering Thermodynamics is presented to undergraduate mechanical engineering students from a classical viewpoint. The emphasis in the courses is on analyzing processes involving bulk thermodynamic properties of materials to ascertain the performance of systems of significant size such as internal combustion engines, steam boiler power plants, vapour compression refrigeration systems, gas compressors etc. This emphasis may need to change so that mechanical engineers gain a better understanding of areas such as nanotechnology, fuel cells, photovoltaic cells and solid state electronics. A further need for change, is because thermodynamics, as a subject, has a reputation that many students apply formulae in a rote-like manner and struggle to understand the underlying physics and practicalities. One of our innovations is to use simple one and two dimensional hard sphere simulations to demonstrate the validity of such basic constants as Avogadro’s Number and the Boltzman constant, and then visually demonstrate the ideal gas equation explaining concepts such as temperature and pressure and the way in which they relate to the volume containing a specified number of molecules. The underlying mechanical/physical reasons for the idealizations and processes of thermodynamics can be visually demonstrated by simple hard sphere models in ways that are related to mechanics. We outline some examples of simple simulations and innovative teaching materials that model the molecular (microscopic) behaviour on which macroscopic thermodynamic behaviour depends. Initial trials of some of the ideas that have appeared in past congress papers have been or are currently being trialed. These trials have revealed how students tend to follow the “rote learning of formulae and procedure approach” rather than the “physical understanding” approach.

Developing Innovative Teaching Materials That Use Molecular Simulations in Engineering Thermodynamics

Volume 6: Engineering Education and Professional Development

2010

Molecular Dynamic Computer Simulation Models for Teaching Thermodynamic Principles

Volume 5: Engineering Education and Professional Development

2011

Modern mechanical engineers need to learn more than the traditional classical approaches to thermodynamics and heat transfer. Matter is comprised of molecules and in many situations the behavior of these molecules may be modeled using hard spheres whose motion is governed by Newtonian mechanics. This is particularly true in those situations involving relatively low density gases, that are valuable in introducing the concepts of thermodynamics. This paper presents some models that have been developed using simple-to-use software that students can handle in a time-efficient way during class-room situations, using only Newtonian Mechanics. Experience indicates that students have many conceptual difficulties when studying engineering thermodynamics. Simple molecular dynamic approaches promise to give students a more intuitive understanding of these thermal areas.

A New Approach to Understanding Engineering Thermodynamics From Its Molecular Basis

Volume 5: Education and Globalization; General Topics

2012

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 molecular workings within the thermodynamic fluid are not of prime concern to the engineer even though they are to a physicist or chemist. Modern engineering thermodynamics textbooks place great emphasis on mathematical systems designed to analyze the behavior and performance of thermodynamic devices and systems, yet they rarely show, at least early in their presentation, graphical images of the equipment; moreover, they tend to give only passing reference to the molecular behavior of the thermodynamic fluid. This paper presents some teaching strategies for placing a greater emphasis on the physical realities of the equipment in conjunction with the molecular structure of the working fluid in order to facilitate a deeper understanding of thermodynamic performance limitations of equipment.