Subject: What does a flame holder do in a ramjet engine?

I have read about ramjet engines and am currently designing one for use on 
a "round-the-world rocket."  A ramjet is the best engine I have though 
of.  They are fast, simple, use normal fuels, air-breathing, and can be 
small but effective.  I have read about ramjets having a "flame holder"  
but haven't found anything as to what exactly it is supposed to do.  This 
is the last step in my design.  Obviously I can't design one if I have no 
idea what it is meant to do.  So the question is, "what exactly is the 
flame holder supposed to do?"  I have read some places where all 
it "seems" to do is mix the fuel but their drawing is just a tube with a 
bunch of holes.  If it's meant to mix the air, wouldn't a series of fins 
cross weaving do better to mix the fuel?  If there is anything I'm leaving 
out, please let me know.  Thank you for any help you can provide.

-Elliot

Re: What does a flame holder do in a ramjet engine?