Numerical Analysis on the Heat Transfer Characteristics of Supercritical Water in Vertically Upward Internally Ribbed Tubes

Internally ribbed tubes (IRTs) with better heat transfer capability have been widely applied in many fields. Several studies focused on the flow and IRTs special structure configurations, but there is still lack of clear understanding regarding influence spiral ribs/grooves local supercritical water. In present paper, numerical simulation turbulent water through a vertically upward investigated. It found at low fluxes, enhancement occurs; temperature IRT lower than that smooth tube by 6~7 °C, high fluxes; deteriorated occurs ST rather IRTs; maximum difference reaches 36 °C. The ratio between about 1.81 pseudocritical region, where velocity deviation 20–50%. Once deterioration exists, thin layer density thermal conductivity so (with 20% reduction) fluids will be covered surfaces. Effects rib height, width, lift angle threads are analyzed, an optimum based performance evaluation criteria obtained (? = 50°, e 0.58 mm, S 3.5 m 6), which can achieve best performance.