Performance of Small High Speed Cryogenic Pumps

Abstract

Several small cryogenic pumps for a liquid rocket engine have been made and tested. These pumps have a small impeller and are characterized by high speed and high head. The main design characteristics of these pumps are as follows: stage specific speeds of from 0.0319 to 0.0766, flow rates from 0.016 to 0.0525 m3/s, pressure rises from 4.9 to 26 MPa, rotational speeds from 16,500 to 80,000 rpm, and impeller diameters from 0.083 to 0.146 m. These pumps, when tested, showed higher efficiency even in the range of small stage specific speeds than any previously reported data on other pumps. This tendency was particularly striking with the two-stage pumps. With regard to pump efficiency measurement, it was made clear that adiabatic efficiency was utilizable for the present cryogenic pumps. The relationship between the adiabatic efficiency and ordinary efficiency was also confirmed by a brief calculation and test results.