The water injection should work. It will probably require more fuel to get the higher thrust, but temps should be lower. If the spray is very fine, and injected near the center of the compressor, it shouldn't hurt anything.

I was discussing water injection with Scott Shockley (driver of the famous Super Shockwave jet truck) just last weekend. He siad the jet car guys have known about water injection for years, but it tends to make their afterurners unreliable, so they don'y use it. After all, most of their show is the afterburner flame and smoke.

Are you testing on a thrust stand? Be sure to record ambient temp/pressure to allow you to adjust for non-standard conditions, as well as exhaust temp, water flow rate, etc.

I'd be very interested in seeing your results!

Bob C.
Silent Wings Airshows