Convection Flashcards
Define convection
Energy or mass transfer between a surface and a fluid moving over the sruface.
Draw the velocity boundary layer
What is the boundary layer thickness equal to?
The thickness when 99% of the bulk velocity, temperature or conentration is achieved - after this the change is very slow so is not relevant.
What is the local friction coefficient for the velocity boundary layer?
What is the shear stress equation?
Draw the thermal boundary layer.
What is the equation for local surface heat flux?
What is the heat transfer mechanism through the boundary layer and why?
Conduction only because there is no motion at the surface.
Define the heat transfer flux by convection.
Define the convection heat transfer coefficient.
Draw the concentration boundary layer.
What is the method of mass transfer in the boundary layer and why?
Diffusion only because there is no fluid motion at the surface.
What is the equation for local surface molar flux?
What is the equation for convection mass transfer?
What is the equation for the convecion mass transfer coefficient?
What is the equation for the average heat transfer coefficient over a length, L?
Show how the velocity boundary layer transitions into laminar flow.
