The Convection and Radiation trainer enables users to match the individual heat quantities to the corresponding type of transfer. The surface temperature of the heated metal cylinder is controlled. Temperature sensors measure the surface temperature of the metal cylinder and the wall temperature of the pressure vessel. The core element is a heated metal cylinder located at the centre of the pressure vessel. In addition to the heating power of the metal cylinder, it is possible to study the heat transport from the metal cylinder to the wall of the pressure vessel.

Under real conditions, the heat transport between two objects is normally substance-bound, i.e. convection and/or heat conduction, and not substance-bound, i.e. radiation, at the same time. Determining the individual heat quantities of one type of transfer is difficult.

It is possible to compare the heat transfer in different gases. In addition to air, nitrogen, helium, carbon dioxide or other gases are also suitable. The pressure vessel can be put under vacuum or positive gauge pressure. In the vacuum, heat is transported primarily by radiation. If the vessel is filled with gas and is under positive gauge pressure, heat is also transferred by convection. 

Heat transport by conduction is largely suppressed by adequately suspending the metal cylinder.

Two pressure sensors with suitable measuring ranges are available for the pressure measurement: a Pirani sensor measures the negative pressure while a piezo-resistive sensor measures the positive pressure. A rotary vane pump generates negative pressures down to approx. 0,02mbar. Positive gauge pressures up to approx. 1bar can be realised with compressed air. 

The measured values can be read on digital displays. At the same time, the measured values can also be transmitted directly to a PC via USB, where they can be analysed with the software.

Specification

Heat transfer between heated metal cylinder and vessel wall by convection and radiation

Operation with various gases possible

Instrumentation: 1 temperature sensor on the metal cylinder, 1 power sensor at the heating element, 1 Pirani Pressure sensor, 1 piezo-resistive pressure sensor

Digital displays for temperature, pressure and heating power

Experiments in vacuum or at a slight positive gauge pressure

Electrically heated metal cylinder in the pressure vessel as experimental vessel

Temperature-controlled heating element

Vacuum generation with rotary vane pump

Software for data acquisition via USB under Windows 8.1, 10.

Technical data:

Pressure vessel

Pressure: -1…1,5bar

Volume: 11L

Pump for vacuum generation

Power consumption: 250W

Nominal suction capacity: 5m3/h

Final pressure with gas ballast: 3*10-3mbar

Final pressure without gas ballast: 3*10-3mbar

Heating element

Output: 20W

Radiation surface area: approx. 61cm2

Measuring ranges

Negative pressure: 0,5*10-3…1000mbar

Pressure: -1…1,5bar rel.

Temperature: 0…250°C

Power: 0…23W

230V, 50Hz, 1 phase

230V, 60Hz, 1 phase; 120V, 60Hz, 1 phase

Dimensions and weight

LxWxH: 1340x790x1500mm

Weight: 160kg.