The effect of particle arrangement on the direct heat extraction of regular packed bed with numerical simulation

Large quantities of industrial waste heat have not effectively utilized, resulting in a waste of energy. To improve the efficiency of waste heat recovery, this paper numerically simulated the effect of particle arrangement on the direct heat extraction of regular packed bed. A verification experiment and the unsteady heat transfer model with 4 stacking structures are established. The influences of porosity, model length, effective contact number and effective angle on the heat transfer time were studied. Temperature distribution, enthalpy, effective heat transfer time, wall heat flux and share of heat transfer were analyzed. The result shows that rhombohedron stack has the largest cooling rate. The change of the particle arrangement has a more obvious effect on the temperature of the particles near cooling wall. Wall heat flux evolution of different stacking structures is consistent with the temperature evolution of particles near cooling wall. Although the contact area of gas phase is more than 20 times that of solid phase, the wall heat flux of the solid phase is much greater than that of the gas phase. The heat transfer process is dominated by solid phase heat transfer. The higher the temperature, the greater the share of radiation heat transfer. •Effect of particle arrangement on heat extraction by numerical simulation.•Four kinds of stacking structures unsteady heat transfer model were established.•Effect of porosity, model length, effective contact number and angle was analyzed.•Rhombohedron stack has better heat extraction characteristics.•These efforts may promote the theory of direct heat extraction from solid material.