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LIQUID HYDROGEN AS A PROPULSION FUEL,1945-1959

Part II : 1950 -1957

5. NACA Research on High-Energy Propellants

High-Energy Propellant Facility

[85] The new $2.5 million rocket facility for high-energy propellants, requested in 1952, was completed in the fall of 1957 (fig.15). It comprised a test cell, propellant supply system, and a unique combination exhaust-gas treatment and silencing system. A service building and high-pressure helium bottles were adjacent to the test cell. Farther away were storage areas for fuels (hydrocarbons, ammonia, hydrazine), liquid oxygen, and water for the scrubber, all piped to the test cell under gravity. Fluorine was loaded into propellant pressure tanks from trailers and a similar provision was made for liquid hydrogen. The oxidizer tanks were in a pit behind the cell, suspended on a weighing system within another tank into which liquid nitrogen was placed as a coolant when...

[86] Fig. 15. The NACA-Lewis high-energy rocket propellant test facility, placed into operation in 1957. The building with the slanted roofs the test cell. The large horizontal duct with vertical stack is the exhaust-gas scrubber and silencer. The two men are in front of racks of high-pressure cylinders of helium used for pressurization. On the far right is the water storage tank and on the far left is the water detention tank and treatment system.

....fluorine was used (fig. 16). The tanks and system were sized to allow three minutes of operation at a thrust of 89 kilonewtons, a considerable increase in size over other high-energy rocket facilities in the country. The exhaust duct at the rocket nozzle exit was 3.7 meters in diameter; the horizontal section, 7.6 meters, and the vertical stack, 6 meters. During a run, water from the 1500-cubic-meter (400 000-gallon) tank on the upper level flowed to the exhaust scrubber at a rate of 190 cubic meters (50 000 gallons) per minute. This was well over a hundred times the mass flow of exhaust gases. The hot gases, emerging from the nozzle at velocities of 3000-4000 meters per second and temperatures of about 2300 K, were met with a drenching spray of water and quickly cooled to steam temperature and slowed to a velocity of about 8 meters per second. Additional water sprays condensed the steam, and the non-condensable exhaust gas emerged from the stack at about 340 K and a velocity of 3 meters per second. The hydrogen fluoride of a fluorine-hydrogen rocket is highly soluble in water; the water containing it was collected in the detention tank. After the run, calcium hydroxide was introduced into the detention tank and the hydrogen fluoride converted. to calcium fluoride-which is inert and harmless-and a slurry of it was pumped into tank trucks and hauled to a dump. The facility was equipped with barrels containing ordinary charcoal and connected to the fluorine system. Harold Schmidt of the rocket research group had found that fluorine reacts readily with charcoal and is converted into inert carbon fluorides-an excellent way to dispose of unwanted fluorine. Monitors to sniff a...

[87] Fig. 16. Sectional view of the NACA-Lewis rocket facility. On the left are high-pressure propellant tanks in pits. The rocket engine and test stand, for vertical downward firing, are dwarfed by the large ducting for exhaust gas scrubbing and silencing.

....variety of gases and combustible mixtures were located at strategic places about the test area. The test cell was controlled by a well-equipped center in the rocket operations building about a kilometer away.