Course detail

# Thermomechanics

FSI-6TT-AAcad. year: 2023/2024

The course is concerned with the following topics: Basic quantities of state. Equation of state of an ideal gas. Mixtures of ideal gases. The First Law of Thermodynamics - heat, work, internal energy, enthalpy. The Second Law of thermodynamics, entropy. Reversible and irreversible processes of gases. The thermodynamics of vapours. Vapour tables and diagrams. The Clausius-Clapeyron Equation. Thermodynamic processes in vapours. Combustion of fuels. Calorific value, heat of combustion. Stoichiometric combustion equations. Stoichiometric ratio, excess air coefficient. Thermodynamics of moist air. Definitive quantities, tables, diagram. Isobaric processes of moist air, evaporation from a free surface. Thermodynamics of flow of gases and vapors. Adiabatic flow through nozzles. The cycles of heat gas and heat steam engines. Compressors. The cycles of cooling devices and heat pumps. Fundamentals of heat transfer. Stationary heat conduction. Heat transfer by convection, similarity theory. Overall heat transfer, heat exchangers. Heat transfer by radiation. Radiation between surfaces.

Language of instruction

Number of ECTS credits

Mode of study

Guarantor

Department

Offered to foreign students

Entry knowledge

Knowledge of mathematics and physics.

Rules for evaluation and completion of the course

A written examination which may include tests (using computers) with emphasis on theory and solving practical examples. An optional part of the examination is an oral examination verifying knowledge from the written part of the examination. Part of the assessment is an evaluation of the exercises, with a minimum of 30 %.

Controlled attendance at exercises, in case of excused absence calculation of substitute examples. Knowledge of the exercises is verified by preparing projects and a test based on the calculation of examples. With the possibility of one correction.

Aims

The course objective is for students to acquire competency to carry out technical computation in the area of thermodynamics and heat transfer. Students will apply theoretical knowledge to machinery and technological fields.

Students will acquire skills to carry out technical computation in the area of thermodynamics and heat transfer: Computation of heat engines and cooling systems. Heat balance of material and machine systems, in gases, vapors, buildings and technological processes.

Study aids

Prerequisites and corequisites

Basic literature

INCROPERA, Frank, David DEWITT, Theodore BERGMAN a Adrienne LAVINE. Principles of heat and mass transfer. 7th ed., international student version. Singapore: John Wiley, c2013, xxiii, 1048 s. ISBN 978-0-470-64615-1. (EN)

Recommended reading

Kreith, F., Bohn, M. S.: Principles of heat transfer. 6th ed., Brooks/Cole, 2001. (EN)

Latif M. Jiji: Heat Transfer Essentials. Begell House; 2 edition, 2002. (EN)

Moran, M. J.: Fundamentals of engineering thermodynamics. 7th ed. Hoboken: Wiley, 2011. (EN)

SUKUMAR Pati Sadhu Singh. Thermal Engineering, 2018 ,Pearson ISBN: 9789353063931 (EN)

Elearning

**eLearning:**currently opened course

Classification of course in study plans

#### Type of course unit

Lecture

Teacher / Lecturer

Syllabus

- Basic terms. Basic laws and equations of state for an ideal gas. Heat capacity.
- Mixtures of ideal gases, Dalton’s Law, equations of state for mixtures and their components.
- The First Law of Thermodynamics and its two mathematical forms. Heat, volume and technical work, internal energy, enthalpy. The First Law of Thermodynamics for an open system and its equations.
- Reversible processes in ideal gases, changes of quantities of state, heat calculation, calculations of internal energy, enthalpy, of volume and technical work, p-v diagrams.

Heat cycles, thermal efficiency, work. The Carnot cycle. The Second Law of Thermodynamics, entropy and general equations for entropy changes. Reversible processes and the Carnot cycle in a T-s diagram. The reversed and irreversible Carnot cycle. Irreversible processes in technical practice. - The cycles of heat steam engines. Combustion engines, gas turbines.
- Van der Waals equations of state for real gases. The thermodynamics of vapour, p-v, T-s and h-s diagrams and vapour tables. The Clausius-Clapeyron Equation. Thermodynamic processes in vapours, changes in quantities of state, heat calculation, calculations of internal energy, enthalpy, of volume and technical work.
- The cycles of heat steam engines. The Rankin-Clausius cycle. The cycles of cooling devices and heat pumps. Combustion of fuels. Calorific value, heat of combustion. Stoichiometric combustion equations. Stoichiometric ratio, excess air coefficient.
- Thermodynamics of humid/atmospheric air. The definition of humidity and enthalpy of humid air, the enthalpy-relative humidity diagram. Cooling, heating, mixing and increasing the humidity of air, adiabatic evaporation from a free surface. Psychrometers.
- Continuity and Bernoulli’s equations. The Prandtl tube, the speed of sound, the Mach number. Isentropic flow of an ideal gas and steam through a narrowing opening and the Laval nozzle and their calculation. The Laval nozzle with various input conditions and the effect of back pressure. Reaction engines
- Heat transfer by conduction. 3D differential equations for stationary and transient heat conduction with an internal source using Cartesian and cylindrical coordinates. Heat and temperature conductivity. Stationary heat conduction through a planar and cylindrical single- and multiple-layer wall.
- Heat transfer by convection. The 3D Fourier-Kirchoff’s equation, The Navier-Stokes equation, boundary conditions. The Similarity Theory in heat convection. Derivation of the criteria of similarity. Criterion equations for natural and forced convection.
- Stationary overall heat transfer through a planar or cylindrical single- or multiple-layer wall. Heat exchangers, the mean temperature logarithmic gradient, algorithms for calculation.
- Heat transfer by radiation. The basic laws (Kirchhoff’s First and Second Law, Planck’s Law, the Stefan-Boltzman Law, Wien’s Law). Radiation between two parallel walls and between mutually surrounding surfaces.

Exercise

Teacher / Lecturer

Syllabus

Calculations:

- State quantities of ideal gas and ideal gas mixture. Calorimetric balance calculations.
- Reversible changes of ideal gas - state variables, heat, work, internal energy changes, entropy.
- Carnot cycle, thermal efficiency, entropy changes. I. Open system law (control volume method)
- Compressors Cycles of internal combustion engines and gas turbines.
- Thermodynamic processes in vapours - state variables, heat, work, internal energy changes, entropy.
- Rankine-Clausius cycle, thermal power plant cycles including nuclear.
- Basic parameters of moist air and its treatment (heating, cooling, mixing, humidification).
- Adiabatic flow through a tapered orifice or Laval nozzle. Design of its main dimensions.
- Cycles of combustion turbines, jet and rocket engines.
- Stationary heat conduction through planar and cylindrical walls, single or compound. Stationary heat transfer - heat transfer coefficient, heat flux
- Heat transfer coefficient by convection and heat flux by convection.
- Basic calculation of a heat exchanger. Radiation between surrounding surfaces.
- Credit test

Elearning

**eLearning:**currently opened course