Explosion using an animated sprite?

I'm an artist trying to create explosions for a game. Detonator is not an option due to the platform (iOS). Haven't had very good results playing with particle systems. (though they're great for smoke and other VFX). I've heard that the best way to make an explosion is to use a sprite animation, but I'm not sure how to go about it. Any ideas?

I'm using 3.5.0f5, and the goal is to have a nice looking explosion that doesn't have too many draw calls.

Keep in mind, I'm an artist who doesn't know much about code, so if your solution involves scripts you'll have to be very specific about how to use them.

Thanks in advance!