Design of forced convection heat transfer rig

Thesis Abstract

This project report contains experimental illustration of forced convective heat transfer rig, which consist of a tube, through which air is sent in by a blower. The test section consists of a long electrical surface heater on the tube which serves as a constant heat flux source on the flowing medium. The inlet and outlet temperature of the flowing medium are measured by thermocouple and also the temperature at several locations along the surface heater from which an average temperature can be obtained. An orifice meter is used to measure the airflow rate with a ‘U’ tube water manometer. An ammeter and voltmeter are provided to measure the power input to the heater. A power regulator is provided to vary the power input to heater. A valve is provided to regulate the flow rate of air. The air being generated by the blower is being passed through a hose connected to a mild steel pipe. The total heat input rate to the air is calculated using
= MCPΔt
Where;
M = Mass flow rate
Cp = Specific heat
Δt = Temperature change of the air across the heating section
Hence, the forced convection heat transfer coefficient is obtained using qt = h.AΔT
Where;
ΔT = log mean temperature across the heating section
The result of the convective heat transfer of h = 0.05 W/m2k was obtained