The Convection Boundary Layers Thermal Boundary Layer Free stream 6,x) Thermal boundary layer 一T,≠To T. A hot or cold plate alters the temperature distribution in the air -Asy-→o:T(y)=T - Asy→0：T(y)=T, The thermal boundary layer thickness is defined as the value at which: T,-Tair(y）=0.99 Ts-Too The thermal boundary layer thickness,t also varies (increases)with x Heat Transfer Su Yongkang School of Mechanical Engineering# 12 Heat Transfer Su Yongkang School of Mechanical Engineering 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, δt also varies (increases) with x 0.99 ( ) = − ∞ − T T T T y s s air Ts ≠ T∞ = T∞ T( y) Ts T( y) =