size of boundary layer
 

hi, everyone!

i have a final project to simulate 2-D combustion chamber in turbojet engine (internal flow)
i wanna ask, what size of boundary layer that should i have?
i set the boundary layer : a = 0.0001
b = 1.5 (ratio)
rows = 20
in that value is difficult to be convergenced
is it ok? or i have to change some value?

i need advice from you all, many thanks:)

The boundary layer height depends on the flow conditions.
You can find formula to calculate it on the help engine of your solver, or on internet.