CRYO-ENGINEERING IN THE NUCLEAR ROCKET PROGRAM

The advantages, principles, and possible configurations of nuclear rocket engines are reviewed, and the development and testing of engines in which hydrogen is heated by a reactor are outlined. The provision, handling, and control of the liquid hydrogen are stressed. (D.C.W.

CRYOGENIC TECHNOLOGY IN THE NUCLEAR ROCKET PROGRAM

Nuclear rocket development problems have resulted primarily from the stringent operational requirements of designing a reactor with optimized parameters of core temperature, rapid start-up capability, ability to withstand extreme temperature gradients, and minimum weight. Disasterous consequences resulting from the entrance of appreciable amounts of liquid hydrogen in the reactor core during start up was feared. Efforts to program the start-up such as to increase the reactor power simuitaneously with the flow rate to prevent two- phase hydrogen from entering the reactor core were attempted. The heat input into the propellant was adjusted as it progressed sequentially through the various portions of the reactor such that the hydrogen entering the reactor core remained well above its critical temperature (33 deg K) during the period that the core inlet pressure was c the critical pressure of hydrogen (12.9 atm). A set of hydrodynamic and heat transfer equations were developed using the transport properties and heat transfer data for fluid hydrogen to produce the necessary start-up program for the reactor. Tests prove that it is possible to start up a reactor on liquid hydrogen. (H.G.G.

TRANSPORT PROPERTIES OF Hesup3sup 3, Hesup4sup 4, Hsub2sub 2, Dsub2sub 2, Tsub2sub 2, AND Ne IN THE LIQUID STATE ACCORDING TO THE QUANTUM MECHANICAL PRINCIPLE OF CORRESPONDING STATES

The principle of corresponding states, in which the state variables were reduced by the molecular parameters of the Lennard-Jones two-body interaction potential and the theory was extended to account for quantum deviations from classical behavior, was used to investigate the liquid state transport properti es of He/sup 3/, He/sup 4/, H/sub 2/, D/sub 2/, Ta, and Ne. The thermal conductivity and viscosity were predicted for the liquid in equilibrium with the vapor along the coexistence curve up to the critical point. The measured positive temperature coefficients of thermal conductivity for the lighter species are consistent with this study. The heavier monatomic species, Ne and Ar, as well as nearspherical molecules such as CH/sub 4/ are observed to deviate from the behavior of the diatomic molecules for both transport properties studied. (auth