Armfield Engineering Education
HEAT TRANSFER AND THERMODYNAMICS
HT12 Radial Heat Conduction - Issue 6
The Armfield Radial Heat Conduction accessory has been designed
to demonstrate the application of the Fourier Rate equation to simple steady-state
conduction radially through the wall of a tube. The arrangement, using a
solid metal disk with temperature measurements at different radii and heat
flow radially outwards from the centre to the periphery, allows the temperature
distribution and flow of heat by radial conduction to be investigated.
Ordering Specification
• A small scale accessory to introduce students to the principles
of radial heat conduction, and to allow the conductivity of a solid brass
disk to be measured.
• Comprises a brass disk with a heater at the centre and a cooling
water tube attached to the periphery.
• Six thermocouples measure the temperature gradient between the heated
centre and cooled periphery of the disk.
• Thermally insulated to minimise errors due to heat loss.
• Heater power variable up to 100 Watts.
• Conduction disk is 110mm diameter and 3.2mm thick.
• The accessory is mounted on a PVC baseplate which is designed to
stand on the bench top and connect to the Heat Transfer Service Unit without
the need for tools.
• A comprehensive instruction manual is supplied.
Technical Details
The accessory comprises a solid disk of material which is heated at the centre and cooled at the periphery to create a radial temperature difference with corresponding radial flow of heat by conduction.
The disk is manufactured from brass 3.2mm thick and 110mm diameter with a central copper core 14mm diameter. The central core is heated by a cartridge type electric heating element which is operated at low voltage for increased operator safety and is protected by a thermostat to prevent damage from overheating. The heating element is rated to produce 100 Watts nominally at 24V DC. The power supplied to the heating element can be varied and measured using the HT10X. The periphery of the disk is cooled by cold water flowing through a copper tube which is attached to the circumference of the disk. Six K-type thermocouples are positioned at different radii in the heated disk to indicate the temperature gradient from the central heated core to the periphery of the disk. The radial distance between each thermocouple in the disk is 10mm. Each thermocouple is fitted with a miniature plug for direct connection to the service unit HT10X. Quick-release connections allow rapid connection of the cooling tube to a cold water supply. A pressure regulator is incorporated to minimise the effect of fluctuations in the supply pressure. A manual control valve allows the flow of cooling water to be varied, if required, over the operating range of 0 -1.5 litres/min. Measurement of cooling water flowrate is not essential to the teaching exercise but an optional turbine type flow sensor can be fitted if required using the quick-release fittings.
The optional flow sensor (Order code SFT2) connects directly to the HT10X
to provide readings of cooling water flowrate directly in litres/min. The
entire radial specimen is located inside a plastic enclosure which provides
an air gap and insulates the section to minimise heat loss to the surroundings
and prevent burns to the operator. The radial heat conduction accessory
is mounted on a PVC baseplate which stands on the bench top alongside the
HT10X.
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 the wall of a cylinder (radial energy flow)
• Determining the constant of proportionality (thermal conductivity
k) of the disk material
Essential Armfield Equipment
HT10X Heat Transfer Service Unit
Optional Armfield Accessories
HT10X-304 Educational Software with USB interface
Requirements
Cold water supply:
1.5 litres/min @ 1 Barg
Shipping Specification
Volume: 0.03m³
Gross Weight: 5kg
Overall dimensions
Height: 0.19m
Width: 0.35m
Depth: 0.18m
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