Fluid-Solid Interaction in Design of Multifunctional Screw Machines

Screw machines operate either as compressors or expanders. Since these functions are accompanied by large pressure and temperature changes, the rotors deform. The calculation of this deformation is very important if the simultaneous expansion and compression in the same pair of rotors is required. To determine these effects, previously developed 3-D numerical methods have been combined into a design management interface to enable simultaneous calculation of fluid flow and rotor deformation with continuous feedback to the elementary design processes. Examples presented in this paper, are the compressor-expanders for fuel cell and high pressure CO2 refrigeration and a two stage compressor in one pair of rotors.