Code Bench top service unit with Code Radiant Heat Exchange And Heat Transfer

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1 THERMODYNAMICS T128D - Heat Transfer Study Units Code Bench top service unit with Code Radiant Heat Exchange And Heat Transfer 1. General The Heat Transfer Study Units Didacta T128D has been designed to carry out experiments concerning the basic modes of heat transfer. A bench top service unit (code ) makes it possible to supply the electrical feedings and measurement facilities. Thus the student can investigate conduction, convection, radiation and their combined effects, non-steady state and measurement errors. The following optional modules can be utilized with the service unit (Code ): Code Linear Heat Conduction Study Unit: a small scale accessory to show the application of the Fourier rate equation; it allows performing an experiment concerning the steady state conduction in one dimension. Code Radial Heat Conduction Study Unit: a small scale accessory to show the application of the Fourier rate equation; it allows performing an experiment concerning the steady state radial conduction. Code Radiant Heat Exchange And Heat Transfer: a small scale accessory to show the law of radiant heat transfer and heat exchange. Code Combined Convection and Radiation Study Unit: a small scale accessory to show the combined effect of convection and radiation; the test allows comparing the practical values to the theoretical expected ones. Code Extended surface Heat transfer Study Unit: a small scale accessory to show the behavior of a heated extended surface, resulting from the combined modes of free convection and radiation. Code Radiation Errors in Temperature Measurements Study Unit: a small scale accessory to show the effect of radiation on temperature meters, especially when the instrument sees the heat source; the student can realize how to reduce or eliminate the errors due to this effect. Code Unsteady State Heat Transfer Study Unit: a small scale accessory to show the temperature distribution in solid samples which are subjected to convection with a fluid at a constant temperature. The unit is supplied with manuals that describe each component of the system, installation and utilization procedures together with customized exercises. DIDACTA Italia S.r.l. - Strada del Cascinotto, 139/ Torino - Italy Tel Fax info@didacta.it

2 2. Composition and description Code Bench top service unit, composed of: Electric control box, complete with circuit breaker and safety devices. Standard connections to the heat transfer modules. Conditioning circuit for up to 10 Pt100 thermoresistances. Low voltage power supply (to the heating elements and to the accessories). Voltmeter indicator. Ammeter indicator. Digital displays for temperatures,r radiometer, luxmeter, anemometer and cooling water flow rate transducer. Sockets OPTIONALS: Code Linear Heat Conduction Study Unit, composed of: Heating element, formed by an electrical resistance (130 W, 48 V DC) which is the thermal source and is assembled inside a copper cylinder to transfer the heat to the specimens. No. 2 known conductivity insulated specimens (copper, aluminum). No. 2 insulated specimens to be tested (mild steel, stainless steel). No. 8 thermoresistances Pt100. Water flow meter, turbine type. Water flow rate regulation valve. Cooling element: a copper hollow cylinder passed through by a water flow rate. Clamping device for the specimens Code Radial Heat Conduction Study Unit, composed of: Heating element, formed by an electrical resistance (100 W approx, 48 V DC) which is the thermal source and is assembled at the centre a brass disk. Cooling element: copper tube, where a cold water rate flows through, attached to the peripheral circumference of the disk. No. 6 thermoresistances Pt100, positioned at different radii. Water flow meter, turbine type; water flow rate regulation valves and temperature probes at inlet and outlet of the module for heat balance evaluation. Code Radiant Heat Exchange And Heat Transfer, composed of: Rigid frame, fitted with rails and sliding carriages. Heat source: copper plate heated by an electric element (200 W approx, 48 V DC) and coated with a black paint to provide a consistent emissivity. Light source (50 W, 48 V DC), complete with filter plates of different opacity and thickness, fitted with glass diffuser: it can turn 180 approx. 7 glass panes of different colors and opacity are also supplied Page 2

3 No. 2 black metal plates (with different surface finishes), grey metal plate and polished plate are supplied to show the effect of emissivity on radiation emitted and received. No. 2 special metal plates which allow demonstrating the area factors. No. 2 Pt100 thermoresistances: the first one is removable and used to measure the heated surface temperature of each metal plate; whereas the other, connected to a safety thermostat, can measure the temperature of the heating source. Radiometer to measure the radiation from the heated plate, to be positioned along the rails and to be connected to the Service Unit. Light meter to measure the radiation from the light source, to be positioned along the rails and to be connected to the Service Unit Code Combined Convection and Radiation Study Unit, composed of: Centrifugal fan, complete with gate to regulate the air flow rate. Anemometer to measure the air velocity Heated cylinder, positioned inside the fan outlet duct. Electric heating element (100 W approx, 48 V DC) No. 2 Pt100 thermoresistances (fitted with a plug for quick connection to the Service Unit) to measure: - Air temperature in the duct. - Wall temperature of the cylinder (mid position). Code Extended surface Heat transfer Study Unit, composed of: Brass bar (rod) with constant diameter: it is assembled horizontally and supported at both ends; the rod is coated with black paint to provide a relevant emissivity Electric heater (25W approx., 48VDC) allowing to heat the rod. Plastic housing for the heated end of the rod to minimise heat loss and to prevent burns to the operator. No. 8 thermoresistances Pt100 attached on the surface of the rod at equal intervals. Code Radiation Errors in Temperature Measurements Study Unit, composed of: Centrifugal fan, complete with throttle plate at the inlet to regulate the air flow rate. Anemometer to measure the air velocity Electric heating element (200 W approx, 48 V DC), to heat a section of the wall of the fan outlet duct; it is insulated on the outside to minimise heat loss and to prevent burns to the operator. Safety thermostat connected to the heating element temperature probe Temperature probe to measure air temperature in the duct. No. 3 temperature probes with different beads to show the differences in the obtained readings. Radiation shield, removable, showing the change in readings when errors in measurements are corrected by means of an insulating shield.

4 Code Unsteady State Heat Transfer Study Unit, composed of: Heated water bath, capacity approx 30 litres, to ensure the stability of the temperature of the water. Cylindrical duct to hold the sample to be tested, complete with a temperature sensor. Electric heating element, 3 kw, complete with thermostat and circuit breaker. Drain valve. No. 2 solid sphere made of materials (brass and stainless steel) which have different thermal conductivities, complete with a temperature sensor to measure the internal temperature of the sample. No. 2 solid cylinder made of materials (brass and stainless steel) which have different thermal conductivities, complete with a temperature sensor to measure the internal temperature of the sample. No. 2 rectangular slab made of materials (brass and stainless steel) which have different thermal conductivities, complete with a temperature sensor to measure the internal temperature of the sample. Variable speed circulation pump to feed the cylindrical duct, so that the water surrounding the sample is at a constant temperature 3. Experiments Code Study of Fourier rate equation for linear thermal conduction. Temperature distribution in a solid for steady state conduction. Calculation of the thermal conductivity. Comprehension of non-steady state conduction. Comparison practical values vs. theoretical values. Code Study of Fourier rate equation for radial thermal conduction. Temperature distribution in a solid for steady state conduction. Calculation of the thermal conductivity. Comparison practical values vs. theoretical values. Code Study of the Stefan Boltzmann law. Study of Kirchoff law. Study of the area factors. Study of the emissivity using heat source, metal plates and radiometer. Study of the Lamberts Law using light source, filter plates and light meter. Comparison practical values vs. theoretical values. Code Determination of the combined heat transfer, due to radiation and convection, from a rod in natural convection. Determination of the influence of the surface temperatures on the convective heat transfer coefficient and radiation heat transfer coefficient. Study (qualitative) of the effect of forced convection. Comparison practical values vs. theoretical values. Code Temperature distribution along an extended surface. Determination of the heat transfer from an extended surface and evaluation of the amount depending on free convection and radiation Comparison practical values vs. theoretical values. Code Errors due to radiative heat transfer: influence of air velocity, wall temperature, sensor beads. Reduction of errors: radiation resistant thermometer, radiation shield for temperature sensors. Comparison practical values vs. theoretical values. Code Temperature distribution in solid samples which are subjected to convection with a fluid at a constant temperature. Study of the effect of shape, size and material properties ion unsteady heat flow. Comparison practical values vs. theoretical values. 4. Required services Electrical power supply: 110/220V, single phase, 50/60 Hz, up to 5kW, depending on the selected modules. Water supply: from mains. Page 4

5 5. Weight and dimensions Code Weight: 15kg approx. Dimensions: 300x400x300 h mm approx. Code Weight: 20kg approx. Dimensions: 500x400x300 h mm approx. Code Weight: 10kg approx. Dimensions: 400x400x300 h mm approx. Code Weight: 10kg approx. Dimensions: 500x300x300 h mm approx. Code Weight: 15kg approx. Dimensions: 300x500x1200 h mm approx. Code Weight: 10kg approx. Dimensions: 300x500x200 h mm approx. Code Weight: 15kg approx. Dimensions: 300x500x1200 h mm approx. Code Weight: 15kg approx. Dimensions: 600x600x700 h mm approx.

6 Cod. R01049/E 1012 Ed. 01 Rev. 03 In any time and without notice, Didacta Italia can carry out any appropriate modification on the product details, always maintaining their main features, according to the designing and teaching necessity. Page 6