Effect of PAG-type lubricating oil on heat transfer characteristics of supercritical carbon dioxide cooled inside a small internally grooved tube (original) (raw)

This study investigates the heat transfer characteristics of supercritical CO2 in a small internally grooved tube with and without the addition of PAG-type lubricating oil. The experiments were conducted within a pressure range of 8-10 MPa and a mass flux range of 800-1200 kg m-2 s-1, with varying oil concentrations from 0% to 5%. It was found that the grooved tube, being the smallest utilized for such studies, significantly impacted the heat transfer coefficients. Results indicate that the presence of PAG-type oil can notably alter the heat transfer dynamics while affecting pressure drop, highlighting the need for further research into the optimized design of cooling systems using supercritical CO2.