In this paper, we analyze the heat transfer modulation produced by the addition of small particles to the base fluid in particle-laden channel flow. We performed direct numerical simulations without gravity at shear Reynolds number
= 150 and molecular Prandtl number
= 3 (liquid-solid flow), using the Eulerian-Lagrangian point-particle approach and considering full (momentum and energy) coupling between the fluid and the particles. For thermally-developing flow, we notice significant changes (up to 10 %) to the fluid heat transfer which can be attributed to particle distribution not yet in equilibrium with turbulence. This transient state promotes the
transfer mechanisms that modify strongly the overall heat fluxes. Results for fully-developed flow show that these changes tend to become negligible once the hydrodynamic and thermal equilibrium is achieved.