A three-velocity three-temperature model for tridisperse porous media is formulated. Using the model, an analytic solution is obtained for the problem of forced convection in a channel between parallel plane walls that are held either at uniform temperature or uniform heat flux. In each case, Nusselt number values are given as functions of conductivity ratios, velocity ratios, volume fractions, and internal heat exchange parameters. (c) 2011 Elsevier Ltd. All rights reserved.