Thermal performance analysis of molten salt in transversely grooved tube for nuclear reactor

Molten salts are prospective candidates for core cooling of advanced high-temperature reactors. In the present work, a numerical investigation is performed to analyze the thermal-hydraulic performance of molten nitrate salt in a transversely grooved tube by varying geometrical parameters. The effect of geometric parameters on Nusselt number, friction factor, and thermal enhancement factor has been expressed in the form of dimensionless factors: groove height to tube diameter ratio (<i>e/d</i>) ranged from 0.038 to 0.092 and groove pitch to diameter ratio (<i>P/d</i>) ranged from 0.5 to 1.5, for Reynolds number ranged from 11,000 to 30,000. Results show that the thermal performance of molten salt in a transversely grooved tube is dominated by geometrical parameters. In general, the Nusselt number and friction factor have been found to be increased with an increase in groove height and with a decrease in groove pitch. The highest value of the Nusselt number is achieved for the highest groove height (<i>e/d</i> = 0.092) and lowest groove pitch (<i>P/d</i> = 0.5) with corresponding maximum pressure drop. As a result, a tradeoff between heat transfer and pressure drop is achieved at <i>e/d</i> = 0.038 and <i>P/d</i> = 1.5 for <i>Re</i> = 11645 for the best overall thermal performance of molten salt in a transversely grooved tube.