Flow System Startup of a Full-Scale Simulated Nuclear Rocket Engine

The performance of the liquid hydrogen flow system during the startup transient of a nuclear rocket was measured in a fullscale simulated engine system at Lewis Research Center. In-flight exhaust conditions were approximated by maintaining a nozzle outlet pressure of 1 psia. Data and general conclusions on overall system performance are presented for non-nuclear operation. The ability of the rocket system to bootstrap (i.e., to build up appreciable hydrogen flow and pressure in the nuclear reactor without extra-system assistance) was clearly demonstrated by using only the energy from hydrogen tank pressure and latent heat of engine components. The severity (small) and characteristics of two-phase flow oscillations during windmill were determined. No significant operational problems were encountered.