INVESTIGATION OF A GAS-DRIVEN JET PUMP FOR ROCKET ENGINES

INVESTIGATIONS OF THE GAS-DRIVEN JET PUMP REVEALED NO FUNDAMENTAL THERMODYNAMICAL OR FLUID MECHANICAL REASON WHICH WOULD PRECLUDE THE PUMPING OF A NET FLOW RATE OF A LIQUID TO A DISCHARGE PRESSURE IN EXCESS OF THE NOZZLE PRESSURE. Gas-consumption between 5.0 and 10.0% should be attainable for these pumps in which the momentum recovery factor of each component is about 0.9. The gas-driven jet pump does not appear applicable to pumping cryogenic propellants or propellants with uncommonly high vapor pressures. The operating characteristics of this pump are strongly influenced by the shape and mechanical design of its components. The velocity recovery factor of the drive nozzle is limited to a value below 0.9 for a drive nozzle employing an injector having a differential pressure of injection which is compatible with the system requirements. Condensibility of the drive gas in the drive liquid is an impediment to the attainment of a high velocity for the 2-phase mixture leaving the drive nozzle. It is possible to mix the drive liquid with the suction liquid, in the mixer, and achieve a momentum recovery in excess of 90%. The volume of the entrained drive gas in the 2-phase mixture entering a properly designed centrifugal separator could be reduced by 95% in flowing through that separator.