Free Convection Heat Transfer Formula. Where q represents the rate of heat transfer per unit surface area λ is the thermal conductivity t is the temperature and y is distance measured from the surface. Heat transfer coefficient heat convected and heat radiated from an isothermal horizontal cylinder assuming natural convection.
The convection calculation is based on rayleigh number and is valid for rayleigh numbers between 10 5 and 1012. The heattransfer coefficient is w m k l nuk h 484 2 4 7207 002685 the heat transfer is q h a ts t 784 wmc2 4 x 10 m2 60 10 c 9675 kw natural convection from finned surfaces finned surfaces of various shapes heat sinks are used in microelectronics cooling. If the flow is laminar heat transfer from the surface is given by the fourier flux law that is.
H heat transfer coefficient wm 2 k s transfer surface m2 tp plate temperature k ta air temperature k for convection we use the convection heat transfer coefficient hc wm 2 k.
In forced convection the fluid molecules are forced to move by an external source. Convective heat transfer is the transfer of heat between two bodies by currents of moving gas or fluid. Free convection heat transfer similar to that under forced convection is characterized by the nusselt number nu αlλ. Heat transfer coefficient heat convected and heat radiated from an isothermal horizontal cylinder assuming natural convection.