Part I : 1945 - 1950

2. Air Force Research on Hydrogen



Pumping Liquid Hydrogen


[25] By 1947, the scope of rocket research at Ohio State had broadened to study pumping of liquid hydrogen, which was carried out by Leroy F. Florant with the assistance of another engineer, Harold F. Snider. They were aware of the German development of a pump for liquid oxygen and of parallel work on liquid hydrogen at Aerojet General beginning in 1948, but their research was the most comprehensive analytical and experimental investigation of liquid hydrogen pumping of the period. They built two facilities-one for using fluids normally liquid at room temperature and the other for low-temperature fluids. They used water and isopentane in the first and liquid nitrogen and liquid hydrogen in the second. In the low-temperature facility the tanks, lines, and valves were vacuum jacketed for insulation. After initial troubleshooting, the system worked well, although there were high liquid hydrogen losses from the conversion of orthohydrogen to parahydrogen (pp. 266-67).


Florant and Snider designed, built, and tested two types of centrifugal liquid hydrogen pumps. They also investigated bearings and seals at speeds up to 10000 RPM. They concluded that centrifugal pumps were a desirable and practical way of pumping liquid hydrogen for rocket engines. They found that water was a satisfactory test fluid for determining and verifying pump design parameters for liquid hydrogen pumps. This facilitated testing and greatly reduced its cost.13


One of the most significant results the two investigators obtained was that properly mounted, precision ball bearings would operate satisfactorily in liquid hydrogen at [26] speeds up to 10000 RPM. The bearings were cooled by the liquid hydrogen and required no lubrication. This useful information was to be rediscovered by Richard Mulready of Pratt & Whitney in 1958 in developing the first flight-model liquid hydrogen-oxygen rocket engine.