Abstract: | Heat and mass transfer at a vertical surface is examined in the case of combined free and forced convection. The boundary layer equations, transformed to ordinary differential equations, contain a parameter that determines the effect of free convection on the forced motion. Criteria are offered for differentiating the free-convection, forced-convection, and combined regimes.Notation x, y
coordinates
- u, v
velocity components
- g
acceleration of gravity
- T
temperature
-
kinematic viscosity
-
coefficient of thermal expansion
- a
thermal diffusivity
- 1
partial vapor density
- D
diffusion coefficient
- W2
mass velocity of air
-
independent variable
- w
shear stress at wall
-
thermal conductivity
- r
latent heat of phase transition
- ,
dimensionless temperature and partial vapor density
- m*
the complex (m
1 –m
1w
)/(1–m(1w
)
- cp
specific heat at constant pressure
- G
Grashof number
- R
Reynolds number
- P
Prandtl number
- S
Schmidt number |