A new approach to modelling micro-explosions in composite droplets

•A new approach to the mathematical modelling of puffing/micro-explosions.•The heat conduction equation inside a composite spherical water/fuel droplet.•Effects of droplet evaporation and swelling on times to puffing/micro-explosion.•Approximations of the dependence of the nucleation temperature on the heating rate.•The effect of the nucleation temperature on times to puffing/micro-explosion.