The flames don't look too much like flames at the moment. I would try a Screen blending mode with some glow emanating from it. Good luck

Well, I tried the screen but the fire just disappeared But I changed it to Multiply and added some glow, hope it looks better Thank you.

Nice idea..I think the biggest problem u have with the flames is that the edges of the fire are hard edges..fire can be really tricky..i would suggest using the smudge tool on the fire layer with different size soft brushes and a strength of like 50+, and just start making random flames coming from the edges(but not too many)..hope that helps author

very nice idea author...its always hard to achieve nice flaming effect especially with dense flames...any how, nice work