Description:
The Free and Forced Convection unit has been specifically designed to demonstrate the phenomena of natural (free) and forced convection. Temperature profiles and heat flux over three different heat transfer surfaces can be easily studied. This unit consists of a bench mounted vertical air duct positioned on the top of a centrifugal fan. The air duct incorporates an aperture positioned at the rear wall of the duct, into which three different types of heat-transfer surfaces can be inserted. The three types of heat exchangers supplied are; flat plate, cylindrical pins and finned surface.
Experimental Capability:
- Relationship between surface temperature and power input in free convection
- Relationship between surface temperature and power input in forced convection
- Understanding of the use of extended surfaces to improve heat transfer from the surface
- Determining the temperature distribution along an extended surface
- Comparing characteristics of a vertical and horizontal flat plate in free convection
- Determining the characteristic velocity, the Reynolds, Grashof and Rayleigh numbers for a flat plate in free convection
- Calculation of the average heat-transfer coefficient of the pinned heater in forced convection
- Comparing horizontal and vertical configurations for a finned exchanger in free convection
Specification:
- A bench mounted unit specifically designed to demonstrate the phenomena of free and forced convection and to measure temperature profiles from three different heat transfer surfaces
- Comprises a vertical air duct, with a transparent front for visibility mounted on a fan at the base of the duct, three heat transfer surfaces, air flow, and temperature probes
- Technical data is included for each of the three heat transfer surfaces, which will enable students and researchers to compare practical results with theoretical analysis for free and forced convection
- Three heat transfer surfaces supplied: a flat plate surface area 0.011m2, pinned extended surface area 0.0525m2, and finned extended surface area 0.1414m2
- Vertical duct incorporates a transparent front wall allowing complete visualisation of the process and identification of the air flow and temperature sensors
- Each heat transfer surface is fitted with its own heater (240W) and thermocouples, to enable easy interchange
- All heat transfer surfaces incorporate guards to permit safe use outside of the duct for performing free convection experiments
- Software includes separate exercises for each of the heat transfer surfaces in free or forced convection and records of all measured variables for analysis and comparison of the performances
- K-type thermocouples measure the air temperature in the duct before and after the heater, as well as the surface temperature of the heat transfer surfaces
- Heater can be voltage or PID controlled allowing for the temperature set-point to be achieved rapidly and maintained within 0.1°C
- The air flow is measured by an air-velocity sensor, which is inserted inside the duct
- Mounted on a PVC baseplate which is designed to stand on the Heat Transfer Service Unit with simple plug-in connections
