The Archimedes Research Unit, funded by the German Research Foundation, addresses the lack of basic knowledge in understanding oil-refrigerant multiphase flows in gaps with moving boundaries, which is crucial for the simulation and design of rotary positive displacement compressors (RPDCs) with liquid injection. This requires a detailed understanding of the occurring flow patterns, which strongly depend on the thermophysical properties of the working fluids and the operating boundary conditions. Archimedes fosters interdisciplinary collaboration and brings together experts in fluid mechanics and thermophysical property research to develop the first validated calculation model for multiphase surge and gap flows of strongly asymmetric oil-refrigerant mixtures. As a first step towards achievi ...