Class I Rocket Engine Static Test, July 19, 2022

For the past year, I've been using a 1/4" stainless steel mist nozzle with a 1.0 mm orifice for all test. With the 1.0 mm orifice, I get an initial oxidizer flow rate of ~ 14.8 ml/sec when pressurized to 140 psig. The same mist nozzle design with a 1.5 mm orifice gives me an ~ 23.0 ml/sec flow rate at 140 psig. Keeping all other parameters the same I got ~ 140 psig pressure spike in the mixing chamber. The pressure spike blew out the nozzle. Next test will have a variable flow control. This should reduce the pressure spike and produce a stable combustion.