CFD analysis on the influence of helix rib on the thermal hydraulics of supercritical water in square annular channel

摘要

This work presents the effects of wrapped rib on thermal hydraulic performance of supercriticalwater in square annular channel. Nine different wrapped pitches and four different cross-sections ofwrapped rib have been tested. The results have been analyzed in terms of pressure drop, secondflow, peaks of temperature and outlet temperature uniformity in the square annular channel. Thereduction in the wrapped pitch is found to enhance the secondary flow velocity and turbulenceintensity, thereby enhancing the thermal mixing of coolant compared to that in smooth channel. Asa result, the temperature field is more uniform in each sub-channel of the channel. However, thereduction of wrapped pitch increases the friction factor. As the wrapped pitch reduce below 300mm,the pressure drop increases steeply. In the same condition of the wrapped pith, the Influence ofcross-section of wrapped rib on the pressure drop and secondary flow is very small, but it influencesthe peaks of wall temperature near rib. The triangle and rectangle with chamfering have the smallerwall temperature peaks than the rectangle and circle.