M E 4210 Lecture Notes - Lecture 14: Heat Transfer, Thermal Conductivity, Heat Flux

• School: Wayne State University
• Department: Mechanical Engineering
• Course: M E 4210
• Professor: Bashar S.Abdul Nour

Document Summary

Heat transfer is the energy transfer due to temperature difference. There are 3 basic modes (i. e. , mechanisms) of heat transfer: conduction, convection, and radiation. Heat conduction is the transfer of energy due to molecular interactions between particles, mostly in solids. It is governed by fourier"s law xq dtak dx. The negative sign is because the heat energy is flowing in the direction of decreasing temperature; i. e. , negative temperature gradient. Convection newton"s law of cooling gradient, flow, m. Heat convection is the energy transfer by the bulk motion of the fluid. It is governed by newton"s law of cooling q = h a (ts - t ) Special lecture a where q = heat transfer rate, w h = convection heat transfer coefficient, w/m2 k (or w/m2 c) T = fluid bulk temperature (flow stream far from the surface), k (or c) Heat radiation is the energy emitted by matter through electromagnetic waves.