MAK 302L HEAT TRANSFER LABORATORY
Experiment 3: Radial Heat Conduction
Nomenclature for Experiment 3
Name
Symbol
SI unit
Inner radius of disk
Ri
m
Outer radius of disk
Ro
m
Radius from center of the disk to thermocouple
Ra (i.e. R1)
m
Thickness of disk (distance)
x
m
Voltage of heating element
V
V
Current of heating element
I
A
Electrical power to heating element
Q
W
Heat transfer rate per unit time(heat flow)
Q
W
Measured temperature
Ta (i.e. T1)
⁰C
Thermal conductivity
K
W/(m⁰C)
Flow rate of cooling water
Fw
l/min
Time
T
sec
1. PURPOSE
To measure the temperature distribution for steady state conduction of energy through the wall
of a cylinder (radial energy flow) and demonstrate the effect of a change in heat flow.
To understand the use of the Fourier Rate Equation in determining the rate of heat flow for
steady-state conduction of energy through the wall of a cylinder (radial energy flow).
To determine the constant of proportionality (the thermal conductivity k) of the disk material.
2. THEORY
When the inner and outer surfaces of a thick walled cylinder are each at a different uniform
temperature, heat flows radially through the cylinder wall. The disk can be considered to be constructed
as a series of successive layers. From continuity considerations the radial heat flow through each of the
successive layers in the wall must be constant if the flow is steady but since the area of the successive
layers increases with radius, the temperature gradient must decrease with radius.
