Estimation of heat transfer parameters in a packed bed

A new method for estimating the "effective" heat transfer parameters using limited measurements and a two-dimensional homogeneous model for a packed bed is presented and compared with existing techniques. The new technique for estimating the parameters is non-sequential and uses the orthogonal collocation method combined with direct or indirect optimization techniques. It has been found that, near the minimum of the objective function, the objective function is not very sensitive to the Biot number but is sensitive to the value of the effective thermal conductivity K_er. This explains why literature values for the effective wall heat transfer coefficient h_w have shown considerable scatter. The new method presented in this paper can give accurate parameter estimates if very accurate data are obtained. Furthermore, the computing time using the new method is far less than for other methods reported in the literature.