NUMERICAL INVESTIGATION ON MITIGATION OF HEAT TRANSFER DETERIORATION OF SUPERCRITICAL CO₂FLOW BY INTRODUCING MULTIPLE TURBULATORS ALONG HELICES IN A CIRCULAR TUBE

In order to effectively alleviate the heat transfer deterioration phenomenon of supercritical CO2 (S-CO2) in a vertical circular tube, explores the fluid hydraulic and thermal performance of multiple turbulator distributed along helices through a verified standard k-ω model. The effects of the pitch and the height of turbulators on flow characteristic and heat transfer are observed and analyzed in detail. With the increase of the height of turbulators, the heat transfer coefficient increases significantly. Besides, as the pitch decreases, the fluid re-circulation area behind each turbulator decreases, resulting in stronger mixing of swirling flow, which enhances turbulent kinetic energy of downstream fluid and weakens buoyancy force, thus mitigating heat transfer deterioration. The present results suggest that introducing multiple turbulators distributed along helices into circular tube can be a beneficial way to alleviate heat transfer deterioration and to enhance heat transfer of supercritical CO2 flow.