Asymmetric heat transfer enhancement in a rotating jet-impingement channel under coupled rotational and crossflow effects

This study numerically investigated the coupled effects of rotation and jet-to-target spacing on flow behavior and heat transfer in a rotating cooling channel with a multi-jet impingement array. Three-dimensional simulations were performed at a fixed jet Reynolds number ( Re j ) of 10,000, with the rotation number ( Ro ) varied from 0 to 0.374 and the jet-to-target spacing ranging from h/D j = 2 to 6. A realizable k–ε turbulence model with enhanced wall treatment was employed based on validation against available experimental data. Rotation produced distinct heat-transfer asymmetry between the leading side (LS) and trailing side (TS), with the magnitude of asymmetry strongly dependent on the jet-to-target spacing. At moderate and large spacings, the LS exhibited higher heat transfer than the TS, with a maximum difference of 11.9% at high rotation numbers. In contrast, the smallest spacing ( h/D j = 2) maintained a momentum-dominated impingement process and resulted in comparatively weak LS–TS asymmetry, with the TS slightly outperforming the LS under some conditions. These results demonstrate that jet-to-target spacing is an important design parameter for controlling the interaction between jet impingement and rotation-induced flow effects, and consequently the heat-transfer distribution in rotating cooling systems.