Research on heat and mass transfer characteristics of water-sprayed single-screw vapor compressor

Abstract

Temperature increase in the working cavity caused by steam superheating is an important issue that affects the compressor performance in single-screw vapor compressor (SSVC). Therefore, working cavity water spraying is often accustomed to realize the cooling of pressurization process. There is a bidirectional phase change process in the SSVC water jet pressurization process, which makes the pressurization and heat transfer mechanism very complicated. To clarify the internal working mechanism, an evaporation-condensation bidirectional heat and mass transfer (HMT) mathematical model of water-vapor two-phase medium is established for the SSVC with multicolumn envelope meshing profile. The simulation results are compared and verified by the experimental data. The exhaust pressure error is within 5%. Based on the validated model, the HMT characteristics are nalysed and the influence of water-sprayed parameters are discussed. Results show that compressor performance can be significantly improved by water spraying, and the volumetric and adiabatic indication efficiency can be increased by 0.98% and 3.83%. After the vapor reaches saturation, with the continuous increase of the water spraying rate, the adiabatic indication efficiency will drop significantly. Conditions such as water-spraying temperature, pressure, suction superheat and back pressure all have an impact on compressor performance.