Direct numerical simulations of heat transfer by solid particles suspended in homogeneous isotropic turbulence

The mechanism of two-phase heat and turbulent transport by small solid particles suspended in a gas flow was investigated by direct numerical simulation in decaying isotropic turbulence with or without a mean temperature gradient. The effect of fluid mean temperature gradient on heat transfer between dispersed and gas phases was examined. Velocity and temperature fields were solved by the pseudospectral method with 128(3) grid points. The behavior of 8,192 particles was time advanced by using the motion and energy equations, The imposed temperature gradient in the fluid affected the Lagrangian autocorrelation coefficient of the fluid temperature along the particle path which decreased more rapidly than that of the particle temperature. The particle temperature fluctuation correlated well with the particle velocity in the direction of the imposed temperature gradient, which was proportional to the magnitude of the gradient, (C) 1998 Elsevier Science Inc. All rights reserved.