Numerical investigation of flow and heat transfer of supercritical water in the water-cooled wall tube

•The fluid temperature and wall temperature will not reach the maximum at the same time.•Local heat transfer enhances before the exit of turning.•Heat transfer coefficients in different circumferential angles reach the peak at different enthalpies.•A new correlation for supercritical water in water-cooled wall tube is proposed. Flow and heat transfer of supercritical water in the 1000MW supercritical boiler water-cooled wall tube were investigated with numerical simulation method. Half of the water-cooled wall tube was heated near the furnace, and heat flux varied along the height of the furnace. The other half of the water-cooled wall tube was in heat insulation. The RNG k-ε model was used in numerical analysis. The influences of buoyancy, centrifugal force, flow deviation, inlet temperature deviation and specific heat on heat transfer were investigated. Buoyancy effect and reduction of thermal conduction of supercritical water lead to heat transfer deterioration, while centrifugal force results in heat transfer enhancement. The heat transfer coefficient increases with the increase of inlet flow rate. Various heat transfer correlations on predicting half-side heating condition were presented and compared. Furthermore, a new heat transfer correlation was proposed for supercritical water in the water-cooled wall tube under half-side heating with non-uniform heat flux.