Screw extruder for solid hydrogen

The first screw extruder capable of continuously forming macroscopic solid hydrogen particles to be injected into the plasma of thermonuclear devices was created and successfully tested. A model of nonisothermal hydrogen flow in the screw channel was developed and used to calculate the extruder efficiency as a function of the system parameters. The results of calculations and experimental data are presented for the extrusion of 500 cm3 of solid hydrogen using an extruder with a working volume of 8 cm3 operating at a rate of 63 mm3/s. Temperature dependences of the viscosity and shear strength of solid hydrogen were studied in the temperature interval from 10 to 13 K, where solid hydrogen behaves like a Bingham fluid.