The Convection Boundary layers Thermal boundary laver Free stream (x) Therma T boundary rer A hot or cold plate alters the temperature distribution in the air Asy→>∞:7()=T Asy→>0:T(y) The thermal boundary layer thickness is defined as the value at which 0.99 T-To The thermal boundary layer thickness, st also varies(increases)with x Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 10 The Convection Boundary Layers Thermal Boundary Layer • A hot or cold plate alters the temperature distribution in the air – As y→: – As y→0: – The thermal boundary layer thickness is defined as the value at which: – The thermal boundary layer thickness, t also varies (increases) with x 0.99 ( ) = −  − T T T T y s s air Ts T =T T(y) Ts T( y) =