Single-phase flow and heat transfer characteristics of transversely non-uniform heated narrow rectangular channels under typical ocean condition

Abstract

The self-shielding effect of plate-type fuel elements leads to non-uniform heat generation across the fuel assembly, which significantly influences the temperature distribution on the channel wall surfaces. Additionally, under periodic external forces, the thermal–hydraulic characteristics within the reactor are altered by the additional inertial forces induced by oscillatory accelerations. This study investigates flow and heat transfer in a narrow rectangular channel with transversely non-uniform heating under marine conditions using numerical calculation methods. It is found that under the stationary vertical upward condition, the local Nu number on the transverse cross-section and the wall temperature distribution exhibit significant differences due to variations in transverse heating power distribution. Under ocean conditions, the influence of Coriolis force on local secondary flow and temperature field is predominantly concentrated near the edge regions of the rectangular flow channel. Rolling and pitching motions induce periodic fluctuations in cross-sectional flow characteristics, Nu number, and local wall temperature, with rolling motion causing stronger periodic fluctuations than pitching motion. For the rolling condition, after increasing both the oscillation angle (from 10° to 45°) and the oscillation period (from 10 s to 5 s) of the periodic force field, it is observed that as the oscillatory acceleration increases, the influence of rolling motion on secondary flow intensity progressively intensifies, while the effect of transverse non-uniform heating gradually diminishes.