Fourier's Law Of Heat Transfer

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net effect is a transport of energy and it takes place in the direction of lower temperature gradient and named as heat transfer by convection. Hence, there are mainly three modes of heat transfer e.g. conduction, convention and radiation. Fourier noticed that the quantity of heat (q) transferred through unit area in unit time is directly proportional to difference of temperatures between the layers and inversely proportional to distance h between them is given by q=ĸ ((T_1-T_2 ))/h, … (1.7)
Where ĸ is the constant of proportionality and known as the coefficient of thermal conductivity. When the distance h between two layers of the fluid is infinitesimal small, then quantity of heat q is given by q=-ĸdT/dy, … (1.8)
Which is called Fourier’s law of heat conduction. Here negative sign shows that the heat flows in the direction of decreasing temperature. The coefficient of thermal conductivity ĸ
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Convection is defined as a process of heat transfer by the combined action of heat conduction and mixing motion. In other words fluid flows over a solid body or inside a channel and if the temperature of solid body and fluid are different, then process due to heat transfer takes place between solid body and fluid is called convection. If the fluid motion is set up by the buoyancy effects resulting from density difference caused by temperature difference in the fluid, the heat transfer is said to be by free convection or natural convection. If the fluid motion is artificially caused by some machine like pump or fan that forces the fluid over the surface and buoyancy forces are negligible in-comparison with forced flow, the heat transfer between surface and fluid caused by forced

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