Searle's bar method
Encyclopedia
Searle's bar method is a method of measuring thermal conductivity
.
Searle's bar method is an experimental procedure to measure thermal conductivity of material. A bar of material is being heated by steam
on one side and the other side cooled down by water
while the length of the bar is thermally insulated
. Then
Q = -kA ((T2- T1) / d) t
Where:
Q is the heat supplied to the bar in time t,
A is the cross-section
al area of the bar,
T1 is the temperature
nearest the heated end,
T2 is the temperature measured a distance d away from the point of T1 measurement ,
k is the coefficient
of thermal conductivity of the bar.
Then energy Q transferred to the cooled end and absorbed by water is:
Q= m Cp (T4- T3)
Where
m – mass of water collected during time t
Cp – coefficient of specific heat capacity (specific heat)
T3 is the temperature of water coming from a reservoir,
T4 is the temperature measured as water leaves
Thermal conductivity
In physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....
.
Searle's bar method is an experimental procedure to measure thermal conductivity of material. A bar of material is being heated by steam
Steam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
on one side and the other side cooled down by water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
while the length of the bar is thermally insulated
Thermal insulation
Thermal insulation is the reduction of the effects of the various processes of heat transfer between objects in thermal contact or in range of radiative influence. Heat transfer is the transfer of thermal energy between objects of differing temperature...
. Then
Q = -kA ((T2- T1) / d) t
Where:
Q is the heat supplied to the bar in time t,
A is the cross-section
Cross section (geometry)
In geometry, a cross-section is the intersection of a figure in 2-dimensional space with a line, or of a body in 3-dimensional space with a plane, etc...
al area of the bar,
T1 is the temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
nearest the heated end,
T2 is the temperature measured a distance d away from the point of T1 measurement ,
k is the coefficient
Coefficient
In mathematics, a coefficient is a multiplicative factor in some term of an expression ; it is usually a number, but in any case does not involve any variables of the expression...
of thermal conductivity of the bar.
Then energy Q transferred to the cooled end and absorbed by water is:
Q= m Cp (T4- T3)
Where
m – mass of water collected during time t
Cp – coefficient of specific heat capacity (specific heat)
T3 is the temperature of water coming from a reservoir,
T4 is the temperature measured as water leaves