Heat and Mass Transfer

Recommended Prerequisites

Termodynamics, Applied Thermodynamics, Fluid Mechanics I, (II), Heat Transfer.

Teaching Methods

The lectures have a traditional format, which is essentially driven by the exposure of the subjects in Powerpoint slides.

The practical classes are devoted to the analysis and solving of practical problems for application of the theoretical knowledge. Some orientations are provided regarding two problems that the student should solve by his own, over the semester, and present the corresponding reports.

Learning Outcomes

The student will obtain deeper and complementary knowledge, as a natural sequence to the unit Heat Transfer. He will also get the capacity to analyze problems involving mass transfer.

First, the mechanism of heat conduction is revisited in specific situations: conduction with internal heat generation, and analysis and sizing of systems with extended surfaces (fins). The physical phenomena of boiling and condensation are characterized, giving the variants of the empirical method for determining the convection coefficient for different situations. As for heat exchangers, the student is taken to apply, in an integrated way, the knowledge acquired so far in both courses for the analysis and design of thermal equipments. Finally, after the basic concepts and fundamental laws, the student will learn the meaning of the mass transfer coefficient and the methodologies for its determination. Emphasis will be given to the analogies between heat, mass and momentum transfer.

Work Placement(s)

No

Syllabus

Complements of heat conduction:

- Conduction with internal heat generation in plane walls and cylinders;

- Extended surfaces. Types and thermal performance of fins. Fin efficiency. Overall effectiveness of a finned surface. Overall coefficient of heat transfer in systems with extended surfaces.

Convection with phase change. Boiling: characteristic curve and regimes. Boiling of a stagnant fluid and in a forced flow. Empirical correlations and methodologies for evaluating the heat flow rate. Condensation: film condensation. Condensation inside ducts. Different methods of analysis and calculation.

Heat exchangers. Different types and modes of operation. Overall heat transfer coefficient. Analysis of heat exchangers: LMTD and effectiveness-NTU methods. Particular cases.

Mass Transfer. Fick's law of diffusion. Diffusion in gases: molecular counter-diffusion; column evaporation. Diffusion in liquids and solids. Mass transfer coefficient. Analogy between heat transfer and mass transfer.

Head Lecturer(s)

José Joaquim da Costa

Assessment Methods

Assessment
Methods of assessment: - Midterm exam; - Exam;: 100.0%

Bibliography

- F.P. Incropera, D.P. DeWitt, T. L. Bergman and A.S. Lavine, Fundamentals of Heat and Mass Transfer, John Wiley & Sons, 6ª ed., 2007.

- Y.A. Çengel, Heat Transfer: a Practical Approach, WCB/McGraw-Hill, 3th ed., 2006.

- F.P. Incropera and D.P. DeWitt, Fundamentos de Transferência de Calor e de Massa, LTC Ed., 4ªed., 1998.

- M.J. Moran, H.N. Shapiro, B.R. Munson and D.P. DeWitt, Introduction to Thermal Systems Engineering: Thermodynamics, Fluid Mechanics, and Heat Transfer, John Wiley & Sons, 2003.

- F. Kreith, Principles of Heat Transfer, McGraw-Hill, 1986.

- A. R. Figueiredo, J. J. Costa e A. M. Raimundo. Apontamentos de Transmissão Calor.