VELLORE INSTITUTE OF TECHNOLOGY CHENNAI CAMPUS
SCHOOL OF MECHANICAL ENGINEERING
BMEE402L
Heat and Mass Transfer
Winter Semester 2023-2024
Dr. Sanjeev Jakhar
Assistant Professor (Sr.), SMEC
Email Id: sanjeev.jakhar@vit.ac.in
BMEE402L Heat and Mass Transfer
Module 6
Wien's displacement law states that the black-body
radiation curve for different temperatures will peak at
different wavelengths that are inversely proportional to the
temperature.
This law states that the monochromatic emissive power of a black
body depends upon absolute temperature of the black body and also
on wavelength of emission.
F12= Fraction of radiation energy leaving surface 1 that reaches surface 2 = 60/100 =0.6
F21= Fraction of radiation energy leaving surface 2 that reach surface 1 =50/100=0.5
1. When the radiation bodies are infinite parallel planes:
2. When the radiation bodies are concentric cylinder or
sphere
3. When a small body in large cavity
Problem 1:- Two very large parallel plates are maintained at uniform temperatures
T1 = 800 K and T2 = 500 K and have emissivities e1 = 0.2 and e2= 0.7, respectively,
as shown in Figure. Determine the net rate of radiation heat transfer between the
two surfaces per unit surface area of the plates
Problem 2:-
Problem 3:-
Problem 4:-
With no radiation shield, the net heat exchange between the parallel
plates
The heat exchange between surface 1-3 and 3-2.
The emissivity of radiation shield is ε3
The shield does not deliver or remove heat
The heat exchange between surface 1-2
Problem 5:-
Problem 6:-
Thank You
