EXPERIMENT No. 2 - HEAT CONVECTIONByZofia Wanczycki - 40019963Helder Melo - 27055137Presented toDr. HaghighatFor the courseBLDG 365 - VP-XThursday February 13th 2019Concordia University
OBJECTIVEThe objective of this experiment is to find the heat coefficient and Nusselt number for heattransfer caused by both free and forced convection. In this experiment, results will be collectedfor a flat plate as well as a finned plate which are the subject of heat transfer. The temperaturechanges will be recorded as well as other values such as the duct traverse probe position and theairflow speed to find other values further in the experiment.INTRODUCTIONThe heat transfer produced in this experiment is due to convection. Heat convection is causeddue to fluid motion which transfers heat between surfaces . Heat convection can be separatedinto two categories: natural, or free, and forced convection.Natural convection, the fluid motion is caused due to natural effects such as buoyancy whichoccurs when an object is immersed in a fluid . Convection caused by buoyancy is created bydensity differences since density differs depending on the temperature . In this experiment, thenatural convection is a result of the air surrounding the heat surface expanding due to heat whichcauses its density to decrease and the air to rise . Cold air then replaces the air and issubsequently heated which causes a convection current .Forced convection is the opposite of natural convection. The fluid motion in this case is due to anexternal force such as a fan, a pump or a mixer . In this experiment, the external force is a fanwhich moves the heated air away from the surface . The faster the fluid motion moves, thehigher the heat transfer rate will be .The convective heat transfer coefficient is important for finding the Nusselt number whichdetermines whether a flow is laminar or turbulent. This coefficient depends on the fluid’sproperties and therefore varies whether the convective heat transfer is natural or forced.Equations are provided to find the heat transfer coefficient and require finding the meantemperature and the heat flow rate.
MATERIALSFree and forced convection apparatusPROCEDURETest 11.Set up the free and forced convection apparatus with a flat transfer surface. The ductneeds to be vertical as this will affect the final results.