58011 - Applied Thermodynamics

Learning outcomes

To acquire knowledge of the basic thermodynamics laws, to know how to evaluate the thermodynamic properties of pure substances through equations and/or databases, to apply thermodynamic analysis to the main processes and transformation cycles in order to calculate the most significant properties involved.

Course contents

Introduction to continuum thermodynamics and macroscopic variables: pressure, temperature and density. Thermal equilbirium, empirical temperature, thermometric scales.

The volumetric properties of pure fluids and their representation on diagrams and tables. The ideal gas law. Phenomenological description of equilbrium between phases for pure substances (LV, SV, LSV), vapor pressure, P-T diagrams, critical point, triple point. The dependence of vapor pressure on temperature: the Clausius-Clapeyron equation, empirical correlations of Antoine and Wagner.

The first law of thermodynamics for a closed and a open system. Internal energy, enthalpy, heat, work and the conservation of energy. Expression of the first law for various systems; constitutive equations, state diagrams and tables. Application of first law to problems of adiabiatic compression and expansion in closed and open systems, evacuation and pressurization of vessels, heat exchangers, isenthalpic valves. Mechanic energy equation and extension to the case of deformable bodies.

The second law of thermodynamics: spontaneous evolution of a system at fixed boundary conditions. Entropy and entropy flux as primitive concepts. Formulation of 2nd law for closet and open systems, consequences and applications of 2nd law for any process, for viscous fluids, and on the meaning of thermodynamic temperature. The 2nd law as a constraint on costituive equations: the first two Mawell's relations. Clausius's and Kelvin's classical formulations of the 2nd law. Calculation of the maximum efficiency of conversion between heat and work, Carnot efficiency. Coefficient of performance for a refrigeration cycle and maximum thermodynamic value. Conversion between heat and work in closed systems: availability function. Minimum work required or maximum work obtainable for a transformation.

Helmholtz and Gibbs free energy; the 2nd law for open, steady state systems, exergy. Maxwell's relations for Gibbs and Helmholtz free energy. Generation of entropy, dissipation of energy. Application of 2nd law to mass transfer between phases: phase equilibrium and derivation of Clausius-Clapeyron equation. Stability criteria for equilibrium states, stability and metastability.

Departure functions from the ideal gas state for a generic state function and their calculation from an equation of state, fugacity. Virial and Van der Waals equation of state. Corresponding state principle: compressibility factor and its dependence on reduced coordinates. Pitzer's acentric factor. Lee Kessler method for the general calculation of volumetric and state properties of fluids. Coefficient of Joule-Thomson.

Power cycles: Carnot cycle, Rankine Cycle. Refrigeration cycles: vapor compression cycles. Representation of cycles on T-S and p-H. Cryogenic cycles: Linde and Claude cycles. Humidification and dehumidification, absolute and relative humidity, dry and wet bulb temperature, psychrometric chart, adiabatic saturation curves. Enthalpy of humid air.

Readings/Bibliography

Zemanski Abbott Van Ness: Termodinamica per ingegneri, Zanichelli

Notes.

Data from:

-Perry's Chemical Engineers Handbook

- Reid Prausnitz Sherwood, The properties of Gases and Liquids, Mc Graw Hill

Teaching methods

Lessons and examples of problem solving.

Assessment methods

One written and one oral exam. The written exam may be replaced by intermediate tests during the course.

Links to further information

http://serwebdicma.ing.unibo.it/deangelis/didattica.htm

Office hours

See the website of Maria Grazia De Angelis