Armfield Engineering Education
HEAT TRANSFER AND THERMODYNAMICS
HT11 Linear Heat Conduction
HT11 Computer Controlled Linear Heat Conduction - Issue 1
The Armfield Linear Heat Conduction accessories are designed to demonstrate the application of the Fourier Rate equation to simple steady-state conduction in one dimension. The units can be configured as a simple plane wall of uniform material and constant cross sectional area or composite plane walls with different materials or changes in cross sectional area to allow the principles of heat flow by linear conduction to be investigated. Measurement of the heat flow and temperature gradient allows the thermal conductivity of the material to be calculated. The design allows the conductivity of thin samples of insulating material to be determined.
On the HT11C the heater power and the cooling water flow rate are controlled
via the HT10XC, either from the front panel or from the computer software.
On the HT11 these are controlled manually.
Right: HT11C Computer Controlled Linear Heat Conduction Accessory
shown with the HT10XC - Service Unit
Ordering Specification
• A small scale accessory to introduce students to the principles of linear heat conduction, and to allow the conductivity of various solid conductors and insulators to be measured.
• Comprises a heating section, a cooling section, plus four intermediate section conductor samples and two insulator samples.
• The heating section, cooling section and one of the intermediate sections are fitted with thermocouples (8 in total) evenly spread along the length of the assembled conduction path.
• All sections are thermally insulated to minimise errors due to heat loss.
• HT11 includes a water pressure regulator and a manual flow control valve.
• HT11C includes a water pressure regulator, an electronic proportioning solenoid valve to control the cooling water flow rate and a water flowmeter.
• Heater power variable up to 60 Watts. Water flow rate variable up to 1.5 litres/ minute.
• Heating and cooling sections, 25mm diameter.
• A comprehensive instruction manual describing how to carry out the laboratory teaching exercises in non-steady state heat transfer and their analysis as well as assembly, installation and commissioning is included.
Experimental Capabilities
> Understanding the use of the Fourier Rate Equation in determining rate of heat flow through solid materials.
> Measuring the temperature distribution for steady-state conduction of energy through a uniform plane wall and a composite plane wall.
> Determining the constant of proportionality (thermal conductivity k) of different materials (conductors and insulators).
> Measuring the temperature drop at the contact face between adjacent layers in a composite plane wall (contact resistance).
> Measuring the temperature distribution for steady-state conduction of energy through a plane wall of reduced cross-sectional area.
> Understanding the application of poor conductors (insulators).
Observing unsteady-state conduction (qualitative only).
Technical Details
The accessory comprises a heating section and cooling section which can be clamped together or clamped with interchangeable intermediate sections between them, as required. The temperature difference created by the application of heat to one end of the resulting wall and cooling at the other end results in the flow of heat linearly through the wall by conduction.
Thermocouples are positioned along both the heated section and cooled sections at uniform intervals of 15mm to measure the temperature gradient along the sections.
A pressure regulator is incorporated to minimise the effect of fluctuations in the supply pressure. A control valve allows the flow of cooling water to be varied, if required, over the operating range of 0-1.5 litres/min. The cooling water flowrate is measured by a turbine type flow sensor (HT11C only).
Four intermediate sections are supplied as follows:
> 30mm long brass section of the same diameter as the heating and cooling sections and fitted with two thermocouples at the same intervals. When this section is clamped between the heating and cooling sections a long plane wall of uniform material and cross section is created with temperatures measured at eight positions.
> Stainless steel section of the same dimensions as the brass section to demonstrate the effect of a change in thermal conductivity.
> Aluminium section of the same dimensions as the brass section to demonstrate the effect of a change in thermal conductivity.
> 30mm long brass section reduced in diameter to 13mm to demonstrate the effect of a change in cross sectional area.
The heat conducting properties of insulators may be found by simply inserting the paper or cork specimens supplied between the heating and cooling sections.
A tube of thermal paste is provided to demonstrate the difference between good and poor thermal contact between the sections.
Accessories
Essential Armfield Accessories
HT11C requires HT10XC Computer Controlled Heat Transfer Service Unit.
HT11 requires either HT10XC or HT10X Heat Transfer service units.
Description
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Requirements
Cold water supply: 1.5 litres/min @ 1 Barg.
All electrical requirements are obtained from the service unit.
Shipping Specification
HT11:
Volume : 0.04 m³
Gross weight: 5 kg
HT11C:
Volume : 0.04 m³
Gross weight: 6kg
Overall dimensions
HT11:
Height: 0.29 m
Width: 0.43 m
Depth: 0.21 m
HT11C:
Height: 0.29 m
Width: 0.43 m
Depth: 0.21 m
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