Sometimes referred to as "Water-Meth" (Methanol) or "Wet Take-Off Power". The methanol is included as an inert agent to prevent the water from freezing, either in the tank, or during the heat transfer referred to above.
A few years ago in northern Manitoba, Canada, an HS-748 was getting ready to depart a small strip. Normal procedure is to arm the water-meth injection prior to throttle up. In this case though, the arming wasn't done until late in the takeoff roll or just after airborne (I can't remember the specific details). Unfortunately, when asked to fuel the airplane earlier, the new fueler mistook the water-meth tank for a fuel tank.
When the kerosene entered the compressor section of both engines, one flamed out, the other exploded in the exhaust section. The plane was deadsticked into a dry river bed with no serious casualties.