Category: COMPUTATIONS IN THERMODYNAMICS

Thermodynamics offers a theoretical framework for the quantification of energy-work interconversions and system equilibrium. The fundamental thermodynamic quantities are introduced in this chapter and the significances of these quantities explained. The importance of accuracy in the volumetric behavior of substances is described and illustrated using the van der Waals equation belonging to the family of EOSs…

Figure 8.7 shows a process on the P-V diagram with an arbitrary process path, wherein a system undergoes a change from its initial state to a final state along the path shown by the solid line. Figure 8.7 An arbitrary thermodynamic process. As stated earlier in the chapter, the types of computational problems, at the elementary level,…

As mentioned in the previous section, the volumetric behavior of a real substance rarely conforms to the ideal gas law. This nonideal behavior requires developing an accurate EOS for determining thermodynamic property changes in processes. Most of the process streams in practice typically consist of mixtures. Even pure product streams typically contain (tolerable) levels of…

The thermodynamic quantities internal energy, entropy, enthalpy, Helmholtz energy, Gibbs energy, and chemical potential provide the framework for the solution of both types of problems previously described. Although the absolute values of the thermodynamic quantities cannot be determined, changes in these properties can be computed accurately. However, these computations require the knowledge of the volumetric behavior of the…

All naturally occurring processes proceed spontaneously until the state of equilibrium is reached where no further net change occurs in the system. The implication of the equilibrium conditions is that the system is not interacting with the surroundings [4]. Understanding this implication is crucial to distinguish between a system at equilibrium and an open system at steady state.…

A system’s properties change when it moves from one state to another. This transformation or process of changing state is inevitably accompanied by heat and work exchange as governed by the first law. When the work and heat effects associated with the process are such that it is feasible to restore the system to its original…

As interconversion between heat and work is the central concern of thermodynamics, it is useful to define thermodynamic properties that are related to the heat content of a system and energy available for conversion to work. This consideration leads to three thermodynamic functions or properties that are mathematically defined as follows: 4. The terms Helmholtz function (or Helmholtz…

Following is the mathematical statement of the first law of thermodynamics for a system, neglecting the changes in the mechanical (kinetic and potential) energy: In this equation, Q is the heat added to the system; W, the work done by the system; and ΔU, the change in the internal energy. The internal energy U can be visualized as the kinetic…

A system is any part of the universe under consideration or that is the focus of thermodynamic analysis. For example, the dashed line shown in Figure 6.10 represents the boundary of a system. The system itself is composed of all the units enclosed within the boundary. The part of the universe that is excluded from the system or is…

The formal concepts of thermodynamics are subtle and require much thought before they are comprehended fully or adequately [2]. The development of these concepts is based on a strong foundation in chemistry, physics, and mathematics, built over several semesters of study. Such development is not attempted here; rather, some essential thermodynamic quantities are introduced in…