CFD simulation analysis of thermo-fluid-dynamic processes in a reciprocating compressor working with CO2

This thesis focuses on the Computational Fluid Dynamics (CFD) simulation of CO2 flow in a reciprocating compressor, particularly examining reed valve dynamics. The primary objectives are to contribute to the understanding of CO2 as a natural refrigerant, optimize compressor design for enhanced efficiency, and reduce energy consumption. Utilizing ANSYS FLUENT, the study involves meticulous preparation and meshing of compressor geometry, dynamic mesh simulations, and the application of a 6 Degree of Freedom (6 DOF) solver. Key aspects studied include the behavior of CO2 in transcritical cycles, valve movement, heat transfer mechanisms, and the impact of valve geometries on compressor performance. The results reveal detailed flow behavior within the compressor chamber, including pressure distribution, velocity profiles, and the formation of vortices. Temperature profiles and heat transfer processes between the suction and discharge chambers are analyzed, highlighting the effects on compressor efficiency and lubricant oil degradation. The study provides a comprehensive understanding of reed valve dynamics, including the impact of valve clearance and geometries on performance. A sensitivity analysis assesses the influence of key parameters such as valve lift and piston stroke frequency on compressor efficiency. The findings facilitate design optimization, proposing recommendations to enhance sealing, reduce mechanical losses, and improve isentropic efficiency. The study offers practical guidelines for the design and optimization of environmentally friendly refrigeration technologies, advancing the application of CO2 as a sustainable refrigerant. This research lays the groundwork for future CFD simulations and numerical analyses of reciprocating compressors, promoting further advancements in the field.