Diffusion Flames

• List four properties of candle flames that you learned in our class discussion.
• What is the key boundary layer assumption that we discussed in class?
• When you blow out a wax candle flame and it appears to “smoke”, what is this smoke made of?
• How does the width of a diffusion jet flame (laminar) change with downstream distance $x$?
• How does the centerline jet velocity change with downstream distance $x$?
• For a given volumetric flow rate, if you double the jet exit diameter, what happens to the flame length?
• If diffusivity increases, what happens to flame length?
• If the stoichiometric mixture fraction changes from 0.05 to 0.1, does the flame length increase or decrease? Does this make sense physically? Why?