SOLID CONDUCTION IN LOW DT/DP BEDS OF SPHERES, PELLETS AND RINGS

Experimental measurements of effective thermal conductivity and wall heat transfer coefficients were made for stagnant annular fixed beds of low tube-to-particle diameter ratio. A wide range of particle shapes, sizes and thermal conductivity was covered. Empirical correlations are given for the wall-to-solid heat transfer coefficient, which becomes important for low d//t/d//p. Predictive formulas for thermal conductivity were tested, and recommendations made on their use. Both parameters were found to be relatively insensitive to particle shape. The results are applied to the estimation of effective conductivity in the cylindrical beds of industrial practice.