The objective of this lesson is to review fundamentals of heat
and mass transfer and discuss:
1.
Conduction heat transfer with governing equations for heat conduction,
concept of thermal conductivity with typical values, introduce the concept of
heat transfer resistance to conduction
2.
Radiation heat transfer and present Planck’s law, Stefan-Boltzmann equation,
expression for radiative exchange between surfaces and the concept of
radiative heat transfer resistance
3.
Convection heat transfer, concept of hydrodynamic and thermal boundary
layers, Newton’s law of cooling, convective heat transfer coefficient with
typical values, correlations for heat transfer in forced convection, free
convection and phase change, introduce various non-dimensional numbers
4.
Basics of mass transfer – Fick’s law and convective mass transfer
5.
Analogy between heat, momentum and mass transfer
6.
Multi-mode heat transfer, multi-layered walls, heat transfer networks, overall
heat transfer coefficients
7.
Fundamentals of heat exchangers
At the end of the lesson the student should be able to:
1.
Write basic equations for heat conduction and derive equations for simpler
cases
2.
Write basic equations for radiation heat transfer, estimate radiative exchange
between surfaces
3.
Write convection heat transfer equations, indicate typical convective heat
transfer coefficients. Use correlations for estimating heat transfer in forced
convection, free convection and phase change
4.
Express conductive, convective and radiative heat transfer rates in terms of
potential and resistance.
5.
Write Fick’s law and convective mass transfer equation
6.
State analogy between heat, momentum and mass transfer
7.
Evaluate heat transfer during multi-mode heat transfer, through multi-layered
walls etc. using heat transfer networks and the concept of overall heat transfer
coefficient
8.
Perform basic calculation on heat exchangers
7.1. Introduction
Heat transfer is defined as energy-in-transit due to temperature difference. Heat
transfer takes place whenever there is a temperature gradient within a system or
whenever two systems at different temperatures are brought into thermal contact.
Heat, which is energy-in-transit cannot be measured or observed directly, but the
effects produced by it can be observed and measured. Since heat transfer involves
transfer and/or conversion of energy, all heat transfer processes must obey the first
and second laws of thermodynamics. However unlike thermodynamics, heat transfer
Version 1 ME, IIT Kharagpur