Thermal, Diffusion and Hydrodynamic Boundary Layer

Question 1

Thermal Boundary Layer

Answer 1

1. find properties for the average temperature
2. calculate whether the flow is laminar or turbulent
3. calculate heat transfer coefficients, h, Nu, thickness using Re and Pr no.
4. find heat flux using q=hadelta T or mcpdelta T
5. calculate temperature using temperature profile

Question 2

Diffusional Boundary Layer

Answer 2

1. calculate Re and Sc number
2. find out flow regime and whether question is on a plate or tube and select equation based on that
3. Use this equation to find mass transfer coefficient
4. Calculate mole flux by Na=hd(Ca-Ca0) and find the moles of the diffusing species in relation to flux
5. Derive the expression for moles of the created species
6. Equate the diffusing and created species, and rearrange to find thickness