Heat and Mass Transfer

Heat transfer: Transient conduction: Fourier´s exact solution for the temperature equalisation in plate/cylinder/sphere; heat conduction in semi-infinite solid; Green´s function of Fourier´s differential equation
Extended surfaces: Energy balance with variable cross sectional area; effectiveness and efficiency of fins; optimisation of a fin profile
Heat transfer with heat source: Spatial varying heat source density; phase change as heat source; melting-solidification ("Stephan-problem"), boiling-condensation (boiling curve according to Nukijama; correlations)
Heat transfer in internal flows: Critical Reynolds-number and entry length; laminar fully-developed flow in tubes; thermal entry region; correlations for further geometries and turbulent tube flow
Radiation Direction dependent emission; view factors; diffusive radiation between grey surfaces; detailed form of Kirchhoff´s Law. Mass transfer: Mass transfer and phase equlibria: concentrations; calculation of phase equilibria; driving force of mass transfer. Diffusion and convection: diffusion coefficient (gas and liquid), Fick's law of diffusion, molar and mass flux, basic equations, special cases (equimolecular diffusion, unimolecular diffusion, dilluted solution), Mass Transfer two phases: equations for mass transfer (²-model), film theory, overall-model and overall mass transfer coefficient, theories of determining the mass transfer coefficient (film theory, penetration theory (surface renewal theory), analogy heat and mass transfer)

After participating in the module Heat and Mass Transfer the students are able to understand the mechnisms of heat and mass transfer occuring in nature and technical applications.They are able make the abstractions from a real problem to a mathematical model. They can analyze systems in regard to heat and mass transfer and distiguish between important and unimportant (negligible) mechanisms.They are able to quatitavely calculate occuring heat and mass flows by using analitical and empirical formulas. The students are able to evaluate the solution to a technical problem and to come up with improvements on their own.

Thermodynamics 1 and WTP (recommended)

In the lecture the contents are provided with the help of presentations and the black board. In exampels practical problems and their solutions are presented. The presentation slides, a formulary and a pool of exercises are supplied. In the exercise lesson problems and their solutions from the above mentioned pool are dealt with. Besides, a supplementary exercise lesson is offered in which thematically similar exercises are discussed in form of (voluntary) homeworks. Students can discuss the problems they had in in the next supplementary exercise lesson. All teaching material and further information are provided online. For exam preparation old exams for the heat transfer part can be downloaded from the website. Individual help will be offered in the office hours of our assistant.

Lecture, Presentation, Black-board, Table-PC with Beamer, Online teaching materials

Polifke und Kopitz, Wärmetransport, 2.Auflage, Pearson-Verlag, 2009; Incropera et al., Heat and Mass Transfer, 6.Auflage, John Wiley & Sons, 2007; Bird, B. R., W. E. Stewart und E. N. Lightfoot: Transport Phenomena. John-Wiley
& Sons, Zweite Auflage, 2002; Cussler, E. L.: Diffusion Mass Transfer in Fluid Systems. Cambridge University Press,
Dritte Auflage, 2009; Mersmann, A.: Stoffübertragung. Springer-Verlag, 1986.

In a written exam (90 min) the candidates are asked to apply the lecture content on different problems. It is allowed to use a non-programmable calculator as well as written documents.