Heat conduction unit H940 (P.A.Hilton Limited)

          The heat conduction unit has been designed to provide students with a sound grounding in the laws governing the transfer of heat by conduction. It also enables the determination of the thermal conductivity of good conductors and of thin specimens of insulating materials. The unit will be of interest in all courses involving heat transfer from technician to the early stages of under-graduate education; (particularly in: Building Services, Chemical Engineering, Energy Management, Plant and Process Engineering and Mechanical Engineering).

          The equipment comprises two heat conducting specimens, a multi-section bar for the examination of linear conduction and a metal disc for radial conduction. An electrical console provides electrical power for heaters in the specimens and digital readout of the temperature at any of the selected points along the heat conducting paths.

• Description of apparatus:

          The P.A. Hilton H940 Heat Conduction Unit, which consists of two heat conducting modules: (a) A multi section bar for linear conduction studies. (b) A metal disc for radial conduction studies. In each module the required temperature difference is achieved by electrically heating and water cooling in the appropriate places. An electrical console provides a controllable supply for the heaters and digital displays of the electrical power input and the temperatures sensed in the modules.

1. Linear Conduction Module: A brass bar is formed from three sections each 25mm dia. clamped together and housed inside an effective thermally insulating sleeve. Comprising: 1- Heat input section- with electric heater and three temperature sensors. 2- Heat sink section- with water cooled surface and three temperature sensors. 3- Centre sections: (a) - brass 25mm dia. (with three temperature sensors). (b) - Brass 13mm dia. (c) - Stainless steel 25mm dia.
2. Radial Conduction Module: Brass disc 110mm dia. 3mm thick with central electric heater and periphal cooling tube-fitted with six sensors.                                           Digital wattmeter: 0 to 100 W  0.1 W.                     Digital temperature indicator: 0.1^oC resolution.

• Experiments done on it:

1. Conduction Along a simple bar:The objective of this experiment is to investigate Fourier’s law for the linear conduction of heat along asimplebar.                                                              In this experiment conduction in an insulated long slender brass bar will be investigated. The bar is of length L, a uniform hot temperature T_h is imposed on one end, and a cold temperature T_c is imposed on the other. The bar is insulated in the peripheral direction, that all the heat flows in the axial direction due to an imposed temperature differential along the bar.The equation that governs the heat flow is known as Fourier's Law, and in the axial direction it .        
2. Conduction Along a composite bar:The objective of this experiment is to study the conduction of heat along a composite bar and evaluate the overall heat transfer coefficient.
3. Effect of Cross-Sectional Area:The objective of this experiment is to investigate the effect of a change in the cross-sectional area on the temperature profile along a thermal conductor.
4. Radial Conduction :The objective of this experiment is to examine the temperature profile and determine the rate of heat transfer resulting from radial steady conduction through the wall of a cylinder.
5. Effect of Surface Contact:The objective of this experiment is to demonstrate the effect of surface contact on thermal conduction between adjacent slabs of material.
   

    

6. Insulation Effects:  The objective of this experiment is to investigate the influence of thermal insulation upon the conduction of heat between adjacent metals.