Direct numerical simulation of momentum and heat transfer for a particle near the no-slip wall

Boundary walls are prevalent in industrial applications, even for heating or cooling fluid–particle systems. However, the momentum and heat transfer characteristics of a particle near the wall boundary layer remain insufficiently explored, especially within the intermediate particle Reynolds number (Re) range of 10–200. In this paper, uniform flow past a hot spherical particle near the no-slip wall is investigated using particle-resolved direct numerical simulation. The velocity, pressure coefficient, spanwise vorticity, and temperature fields are analyzed to elucidate the influence of the wall boundary layer on the full set of parameters, including drag coefficient (CD), lift coefficient (CL), torque coefficient (CT), and Nusselt number (Nu). The results indicate the formation of a distinctive hydrodynamic boundary layer near the wall, where local velocity initially increases and then decreases, approaching the mainstream velocity. The CD attains its maximum value near the edge of the hydrodynamic boundary layer owing to the locally high velocity. Both CL and CT are significantly higher than those in unbounded uniform flow. Furthermore, the compression of the temperature boundary layer beneath the particle by the wall significantly enhances heat transfer, with the local Nu at a dimensionless particle–wall distance of L = 0.51 reaching up to 30 times higher than in the absence of wall effects for Re = 10. Finally, comprehensive predictive correlations for CD, CL, CT, and Nu are developed. Notably, the combined effects of L and Re on CD, CT, and Nu are effectively captured through the normalized particle–wall distance relative to the boundary layer thickness.