Conduction • Fourier’s Law q : Heat transfer rate : Temperature gradient in direction of the heat flow
Heat Conduction Analysis- 1 D 1 -D (plane wall) Situation: Consider general case where T changing with t & heat source present within the body. So, the energy balance;
Heat Conduction Analysis- 1 D 1 -Dimension Heat Conduction general equation:
Heat Conduction Analysis-3 D Spherical coordinates Cartesian coordinates Cylindrical coordinates
Cartesian coordinates
Cartesian coordinates General 3 -Dimension Heat Conduction equation: If, k = constant Thermal Diffusivity of the material
Thermal Diffusivity • The larger value of α, the faster heat will diffuse through the material. • So, α can be higher value if i) Thermal conductivity, K higher ii) Thermal heat capasity, ρc lower
Heat Conduction Analysis- 3 D Cylinder Coordinates Sphere Coordinates
Analysis: conclusion Steady-state 1 D heat flow (no heat generation): Steady-state 1 D heat flow in cylinder coordinates (no heat generation): Steady-state 1 D heat flow with heat sources: 2 D Steady-state conduction without heat sources: