Method of calculating cooldown process in cryostat of cryogenic electric machine
Abstract
Thermophysical processes in the cryostat of cryogenic electric machines during successive cooldown with nitrogen and helium are analyzed. The cryostat performance is calculated and the existence of heat transmission paths from the ambient medium to the magnetic structure is considered. The thermal model of the machine includes the shield as an added mass. The mathematical model of the cooldown process consists of two differential equations of heat transfer for two heat exchangers in the system. The system of four equations with four equations with four unknown temperatures is solved simultaneously. Numerical integration of the differential equations is performed with a variable step cope with the fast decrease of thermal capacities upon approach to liquid helium temperatures.
 Publication:

USSR Rept Electron Elec Eng JPRS UEE
 Pub Date:
 March 1985
 Bibcode:
 1985RpEEE.......50V
 Keywords:

 Computer Programs;
 Cryogenics;
 Cryostats;
 Gas Cooling;
 Heat Transfer;
 Liquid Cooling;
 Differential Equations;
 Liquid Helium;
 Liquid Nitrogen;
 Mathematical Models;
 Numerical Analysis;
 Temperature Control;
 Engineering (General)