EDIT: I hacked together a very quick and dirty little demo app to see the generated explosions in motion. You can download the zip here. It's crude, since I just pieced it together in about an hour or so, but it works okay. The app will generate 6 explosion sequences, then randomly spawn explosions on a grey field. You can also spawn an explosion at the mouse cursor by clicking a mouse button. The periodic explosions are governed by the global variable threshold. The app is also a Lua interpreter, you can enter text via the console window at the bottom. Try changing the value of threshold to higher numbers (in the range of 1 to 100) to increase the spawn rate. Default threshold is 10. The app will save the generated sequence to TGAs named sequence.tga in the base directory.

From what I can see, the color scale could use a little tweaking, and it seems like the smaller you make the animation range of the turbulence translation, the better the results. Although no translation seems kinda ugly. Could stand to have the other parameters tweaked, but as it stands I'm satisfied, and I am done with explosions.
/EDIT

Regarding the explosions in the last post:

You can dramatically alter the character of the created fireball by using different basis functions for the density function. All it is is a perturbed sphere, so by using different types of noise for the turbulence, you get different shapes. This image was created using a Ridged Multifractal basis rather than a Hybrid Multifractal.



And this one uses an FBM basis:



With a little more tweaking, using a constant source as a blend mask between two different varieties of noise, and changing the constant at each frame, you can even change the basis function over time.

Up next, though, is a test to see them in animation to see if they're really any good when in use.