Abstract: Particle-laden turbulent channel flow is prevalently manifested in natural and engineering applications, so the investigation of its flow and heat transfer characteristics holds significant importance. In this paper, the effect of the particle size dispersity of radiatively heated particles on particle distribution morphology and its modulation effect on the flow in vertical turbulent channel flow were investigated. Direct numerical simulation was used for fluid phase, and Lagrange-point tracking model was used for particle phase. The momentum and heat exchange between particles and fluid were considered. The research results reveal that the multi-scale turbulent structure exerts distinct centrifugal effects on particles with different particle sizes in the flow field, leading to the accumulation of polydisperse particles at disparate positions and resulting in a more homogeneous distribution of polydisperse particles in the flow field compared to that of monodisperse particles. Moreover, the spatial position distribution of the particles influences the interphase energy exchange, such that compared to the heated monodisperse particle-laden turbulent channel flow, the heated polydisperse particles accelerate the interphase momentum and heat exchange, enhance the momentum and temperature of the fluid, and concurrently avoid the temperature extremum in the flow field.

Key words: particle size dispersity, sparse two-phase turbulent flow, direct numerical simulation, partical-laden turbulent