Brewer needs lesson in thermodynamics.

[Birdboybrewing]

I'm starting a brewery and need some help designing a brew kettle. I haven't found much in the brewing community about how a brew kettles firebox is laid out. I've got a tank that is 45" wide and 48" tall and I'm planning on heating it with a 400k btu forced air burner, basically like a small jet engine. But in order to heat efficiently I'm thinking it needs some baffles between where the gas is blown in and the exhaust. I'll include a sketch of the kettle, but i need help laying out the best possible gas flow pattern for efficiently heating the thing, please help me. Here's a good forum post on it, but doesn't help me much. http://discussions.probrewer.com/showthread.php?18370-Brew-Kettle

 

[Birdboybrewing]

The fire box is the area under the kettle sorry it's not labeled very well in the sketch.