Elasto-hydrodynamic performance investigation and optimization of gas foil bearings-rotor system for green vapor compression refrigeration cycle

A vapor compression refrigeration cycle with gas-bearing and green refrigerants holds great potential for addressing global warming by reducing greenhouse gas emissions and enhancing efficiency. A gas foil bearings-rotor system containing a viscous refrigerant is critical to affecting the energy efficiency and reliability of the green refrigeration cycle. Therefore, the mathematical model accounting for the compressible viscous flow of the refrigerant is presented for the system in this paper. The influence mechanisms of refrigerant type and structural and operational factors on the elasto-hydrodynamic performance are investigated by the mathematical model. Multi-objective optimization considering simultaneously load capacity, refrigerant vapor film pressure, and damping is conducted by nonlinear regression analysis and genetic algorithm to determine the optimal system. Compared to average and maximum values, the load capacity increases by 3.43 times, the refrigerant vapor film pressure increases by 1.18 times, and the damping decreases by 38% for the optimal system. These findings have great significance for improving the efficiency and reliability of green and sustainable refrigeration cycles to reduce greenhouse gas emissions.