Abstract: A novel scroll multiphase pump for transporting gas-liquid mixtures is proposed. In this multiphase pump, the compression chamber has a pressure unloading gap towards discharge port by constructing changing meshing clearances wrap profiles. During the compression process, the pressure of the gas-liquid mixtures increase as the reduction of compression chamber volume, simultaneously few gas liquid mixtures are pushed into the discharge port through the pressure unloading gap. Therefore, the problem of pressure surge in compression chamber is resolved. The geometric theories and the mathematical model of compression process with internal leakage for scroll multiphase pumps are established, and the changing relation between parameters of gas-liquid mixtures in compression process is obtained. The numerical simulation of working process in multiphase pump, which is gas-liquid mixtures compression process and an unsteady flow with moving boundary, is processed, and the velocity distribution and pressure distribution of working chambers are obtained. The influences of gas volume fractions, the reduction rate of compression volume and meshing clearance on compression process are analyzed. The study results formed design theories of scroll multiphase pumps.

Key words: Compression process model for gas-liquid mixtures, Design theories, Geometric theories, Numerical simulation, Scroll multiphase pumps, clearance, meshing position, meshing property, misalignment, planetary roller screw mechanism