Calculation of cryogenic evacuation of directed gas flows using spherical and cylindrical surfaces
Abstract
An approximate method is described for calculating cryogenic evacuation by spherical and cylindrical surfaces at constant and variable temperature of the condensing wall. A spherical or cylindrical surface is considered, on the inner surface of which condensation of a gas to solid phase is taking place. The gas is flowing out from a source at the center of the surface, and it is required to determine the period of time over which steady flow conditions are maintained inside the volume bounded by a surface of radius less than that of the cylinder or sphere. The problem is solved by replacing the condensation surface by an equivalent gas space whose parameters at infinity are simply related to the saturated gas parameters at the temperature of the condensate surface. Solution of the problem is reduced to finding the radius of the jump that forms in the equivalent gas as a function of time. Pressure of the equivalent gas is variable and is determined by thermophysical processes on the condensate surface, in its layer, and in the wall itself.
 Publication:

TsAGI Uchenye Zapiski
 Pub Date:
 1974
 Bibcode:
 1974ZaTsA...5..124V
 Keywords:

 Cryogenics;
 Evacuating (Vacuum);
 Gas Flow;
 Cylindrical Bodies;
 Spheres;
 Temperature Distribution;
 Thermal Conductivity;
 Wall Temperature;
 Fluid Mechanics and Heat Transfer